Plant, Cell & Environment

Cover image for Vol. 38 Issue 9

Early View (Online Version of Record published before inclusion in an issue)

Edited By: Keith Mott

Impact Factor: 6.96

ISI Journal Citation Reports © Ranking: 2014: 7/200 (Plant Sciences)

Online ISSN: 1365-3040

VIEW

  1. 1 - 76
  1. Commentary

  2. Original Articles

    1. Seed set, pollen morphology and pollen surface composition response to heat stress in field pea

      YUNFEI JIANG, RACHID LAHLALI, CHITHRA KARUNAKARAN, SAROJ KUMAR, ARTHUR R. DAVIS and ROSALIND A. BUECKERT

      Article first published online: 19 AUG 2015 | DOI: 10.1111/pce.12589

      Pea (Pisum sativum L.) is a major legume crop grown in a semi-arid climate in western Canada, where heat stress affects pollination, seed set and yield. Using two commercial cultivars, we found that successful seed set under heat stress in field pea was associated with differences in in vitro pollen germination, pollen tube growth, thickness of the intine and pollen surface composition.

    2. Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation

      NÚRIA GARCIA-FORNER, HENRY D. ADAMS, SANNA SEVANTO, ADAM D. COLLINS, LEE T. DICKMAN, PATRICK J. HUDSON, MELANIE J.B. ZEPPEL, MICHAEL W. JENKINS, HEATH POWERS, JORDI MARTÍNEZ-VILALTA and NATE G. MCDOWELL

      Article first published online: 8 AUG 2015 | DOI: 10.1111/pce.12588

      Stomatal regulation of leaf water potential in response to declining water availability (isohydric vs. anisohydric behaviour) is believed to be one of the key components of plant drought responses, and has been given a central role in theories addressing the mechanisms underlying drought-induced mortality. We studied the physiological performance of two species with contrasted behaviors (Pinus edulis: isohydric, Juniperus monosperma: anisohydric) under experimental drought and heating treatments. Contrary to expectations both species exhibited similar stomatal conductance dynamics in response to drought, and hydraulic safety margins were broader in the anisohydric species. We conclude that direct association of stomatal behavior with risk of hydraulic failure can be misleading and instead, advocate a more integrative approach incorporating stomatal and xylem responses to declining water potential.

    3. SlDREB2, a tomato dehydration-responsive element-binding 2 transcription factor, mediates salt stress tolerance in tomato and Arabidopsis

      IMÈNE HICHRI, YORDAN MUHOVSKI, ANDRÉ CLIPPE, EVA ŽIŽKOVÁ, PETRE I. DOBREV, VACLAV MOTYKA and STANLEY LUTTS

      Article first published online: 8 AUG 2015 | DOI: 10.1111/pce.12591

      Herein we characterized the tomato SlDREB2 transcription factor in response to salinity. Arabidopsis thaliana and Solanum lycopersicum plants overexpressing this regulator displayed improved tolerance to salinity following adjustment of transcriptional, hormonal, physiological and biochemical parameters related to salt-stress response.

    4. Three-dimensional microscale modelling of CO2 transport and light propagation in tomato leaves enlightens photosynthesis

      QUANG TRI HO, HERMAN N. C. BERGHUIJS, RODRIGO WATTÉ, PIETER VERBOVEN, ELS HERREMANS, XINYOU YIN, MOGES A. RETTA, BEN AERNOUTS, WOUTER SAEYS, LUKAS HELFEN, GRAHAM D. FARQUHAR, PAUL C. STRUIK and BART M. NICOLAÏ

      Article first published online: 28 JUL 2015 | DOI: 10.1111/pce.12590

      We present a comprehensive 3-D model of light propagation, CO2 diffusion and photosynthesis in tomato (Solanum lycopersicum L.) leaves. The model incorporates the actual leaf microstructure and opens up new possibilities for in silico approaches to improving insights into leaf carbon uptake and to predicting climatic impacts on crop yield and vegetation.

    5. Manipulation of the hypocotyl sink activity by reciprocal grafting of two Raphanus sativus varieties: its effects on morphological and physiological traits of source leaves and whole-plant growth

      DAISUKE SUGIURA, ERIKO BETSUYAKU and ICHIRO TERASHIMA

      Article first published online: 28 JUL 2015 | DOI: 10.1111/pce.12573

      In this article, we conducted reciprocal grafting experiments using two varieties of Raphanus sativus with high or low hypocotyl sink activities to reveal whether hypocotyl sink activities are regulated by the above-ground parts. We also tested how physiology and morphology of source leaves and whole-plant growth are affected by the hypocotyl sink activities through the accumulation of total nonstructural carbohydrates (TNC) in the source leaves.

      Our results show that (1) the hypocotyl sink activity is not affected by the above-ground parts and determined autonomously in the hypocotyls; (2) whole-plant growth was highest in the grafted plants with lowest sink activity; (3) the feedback regulation of photosynthesis was not induced by the accumulation of TNC; (4) leaf morphological traits could be also affected by the sink activity through the accumulation of TNC. These findings will help us understand mechanisms regulating the hypocotyls growth and leaf development in relation to sink-source balance.

    6. Inoculation with an enhanced N2-fixing Bradyrhizobium japonicum strain (USDA110) does not alter soybean (Glycine max Merr.) response to elevated [CO2]

      ÁLVARO SANZ-SÁEZ, KATY D. HEATH, PATRICIA V. BURKE and ELIZABETH A. AINSWORTH

      Article first published online: 28 JUL 2015 | DOI: 10.1111/pce.12577

      This study tested the hypothesis that legume productivity responses to elevated [CO2] could be improved by inoculation with selected rhizobial strains with enhanced N2 fixation and carbon consumption. Inoculation of soybean in the field with a selected strain (USDA110) significantly increased nodule occupancy, but did not result in greater photosynthesis, growth or seed yield at ambient or elevated [CO2], likely because of competition from native less effective rhizobia. In sterile soil, inoculation with USDA110 significantly increased 15N2 fixation, photosynthetic capacity, leaf N and total plant biomass compared to plants grown with native soil bacteria, but there was no interaction with elevated [CO2]. Thus, both field and controlled environment experiments showed that inoculation with better-quality rhizobia did not enhance soybean responses to elevated [CO2].

    7. Differential CO2 effect on primary carbon metabolism of flag leaves in durum wheat (Triticum durum Desf.)

      IKER ARANJUELO, GORKA ERICE, ALVARO SANZ-SÁEZ, CYRIL ABADIE, FRANÇOISE GILARD, ERENA GIL-QUINTANA, JEAN-CHRISTOPHE AVICE, CHRISTIANA STAUDINGER, STEFANIE WIENKOOP, JOSE L. ARAUS, JACQUES BOURGUIGNON, JUAN J. IRIGOYEN and GUILLAUME TCHERKEZ

      Article first published online: 16 JUL 2015 | DOI: 10.1111/pce.12587

      Although ear emergence strongly alters C/N partitioning in wheat, phenology driven modifications in leaf in proteomic profile, metabolite content and nutrition of wheat exposed to elevated [CO2] remain to be elucidated. Our study revealed that, compared with vegetative stage, growth at elevated CO2 altered photosynthate export and tended to accelerate leaf N remobilization during grain filling period. Protein derived N remobilization modulated leaf proteins and amino acids profile. Finally our study highlighted the fact that under elevated [CO2] nitrogen use efficiency improvement might represent a target goal for breeding programmes.

    8. Rice potassium transporter OsHAK1 is essential for maintaining potassium-mediated growth and functions in salt tolerance over low and high potassium concentration ranges

      GUANG CHEN, QINGDI HU, LE LUO, TIANYUAN YANG, SONG ZHANG, YIBING HU, LING YU and GUOHUA XU

      Article first published online: 16 JUL 2015 | DOI: 10.1111/pce.12585

      A rice potassium transporter, OsHAK1, is up-regulated by K deficiency or salt stress in various tissues, particularly in the root and shoot apical meristem. Knockout of OsHAK1 reduced the K absorption rate of unit root surface area by ∼50–55% and ∼30%, and total K uptake by ∼80% and ∼65% at 0.05–0.1 mM and 1 mM K supply level, respectively. The positive relationship between K concentration and shoot biomass in the mutants suggests that OsHAK1 plays an essential role in K-mediated rice growth over low and high K concentration ranges.

    9. Evidence for ACD5 ceramide kinase activity involvement in Arabidopsis response to cold stress

      CHRISTELLE DUTILLEUL, HEIDY CHAVARRIA, NATHALIE RÉZÉ, BRUNO SOTTA, EMMANUEL BAUDOUIN and ISABELLE GUILLAS

      Article first published online: 16 JUL 2015 | DOI: 10.1111/pce.12578

      The formation and function of ceramide phosphates (Cer-P) has been explored in chilled Arabidopsis. A rapid and transient formation of Cer-P occured in cold-stressed WT plantlets and cultured cells, that was strongly impaired in acd5 mutant. acd5 seed germination appeared hyper-sensitive to cold and ABA, and ABA-dependent gene expression was modified in acd5 seeds germinated at low temperature. Our data involve for the first time Cer-P and ACD5 in low temperature response and further underline the complexity of sphingolipid signalling operating during cold stress in Arabidopsis.

    10. FERONIA receptor kinase interacts with S-adenosylmethionine synthetase and suppresses S-adenosylmethionine production and ethylene biosynthesis in Arabidopsis

      DANDAN MAO, FENG YU, JIAN LI, BRAM VAN DE POEL, DAN TAN, JIANGLIN LI, YANQIONQ LIU, XIUSHANG LI, MENGQIU DONG, LIANGBI CHEN, DONGPING LI and SHENG LUAN

      Article first published online: 16 JUL 2015 | DOI: 10.1111/pce.12570

      Highlighting

      The receptor-like kinase FERONIA, which plays important role in the plant development and environment response, can interacts with S-adenosylmethionine (SAM) synthesis and down-regulates SAM and ethylene biosynthesis.

    11. The saccharopine pathway in seed development and stress response of maize

      EDUARDO KIYOTA, IZABELLA AGOSTINHO PENA and PAULO ARRUDA

      Article first published online: 16 JUL 2015 | DOI: 10.1111/pce.12563

      Although ear emergence strongly alters C/N partitioning in wheat, phenology driven modifications in leaf in proteomic profile, metabolite content and nutrition of wheat exposed to elevated [ CO 2 ] remain to be elucidated. Our study revealed that, compared with vegetative stage, growth at elevated CO 2 altered photosynthate export and tended to accelerate leaf N remobilization during grain filling period. Protein derived N remobilization modulated leaf proteins and amino acids profile. Finally our study highlighted the fact that under elevated [ CO 2 ] nitrogen use efficiency improvement might represent a target goal for breeding programmes.

    12. The enigma of effective path length for 18O enrichment in leaf water of conifers

      JOHN RODEN, ANSGAR KAHMEN, NINA BUCHMANN and ROLF SIEGWOLF

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12568

      This study measured the variation in the stable oxygen isotopic composition of needle water for six conifer species. Although the Péclet correction of leaf water evaporative enrichment has been used extensively in predictive models (many of which have been published in PC&E), conifer needles can sometime produce results that are odd in reference to Péclet theory or leaf anatomy. Due to the importance of conifers for long-lived tree ring isotope records and their massive ecosystem effects on biogeochemical cycles, this study could impact diverse research fields that require accurate estimates of conifer leaf water evaporative enrichment.

    13. The potassium transporter OsHAK21 functions in the maintenance of ion homeostasis and tolerance to salt stress in rice

      YUE SHEN, LIKE SHEN, ZHENXING SHEN, WEN JING, HONGLIANG GE, JIANGZHE ZHAO and WENHUA ZHANG

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12586

      We investigated a highly salt-induced high-affinity K+ transporter (HAK) gene, OsHAK21. OsHAK21 is localized in the plasma membrane, and expressed in xylem parenchyma and passage cells. Knockout of the OsHAK21 gene led to an increased Na+/K+ ratio and salt sensitivity. These results highlight the importance of OsHAK21-mediated K+ acquisition for maintaining Na+/K+ homeostasis under salt stress.

    14. Leaf hydraulic conductance varies with vein anatomy across Arabidopsis thaliana wild-type and leaf vein mutants

      MARISSA A. CARINGELLA, FRANCA J. BONGERS and LAWREN SACK

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12584

      Leaf venation is diverse across plant species and has practical applications from paleobotany to modern agriculture, yet the impact of vein traits on plant hydraulic performance has not yet been tested in a model system such as Arabidopsis thaliana. We measured leaf hydraulic conductance (Kleaf), vein traits, and xylem and mesophyll anatomy for A. thaliana wild-type (WT) and vein mutants, and found that genotypes varied quantitatively in Kleaf, vein traits and leaf anatomy. The WT had significantly higher Kleaf, and across all genotypes there was strong correlation of Kleaf with traits related to hydraulic conductance across the bundle sheath, suggesting a critical role for the bundle sheath in influencing Kleaf. These findings highlighting the usefulness of a mutant system for testing and extending theory that was primarily established comparatively across species.

    15. Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species

      MARKUS NOLF, DANIELLE CREEK, REMKO DUURSMA, JOSEPH HOLTUM, STEFAN MAYR and BRENDAN CHOAT

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12581

      Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply, but the relationship of such traits within the plant hydraulic continuum remains largely understudied. In this study we analysed the hydraulic vulnerability, pressure-volume relations and in situ water potentials of three tropical rainforest species. We found that hydraulic parameters in stems and leaves were finely coordinated to avoid embolism formation in the xylem, with very narrow safety margins (leaf P 50 – stem P 50) and a strategy of sacrificing leaves in favour of stems.

    16. OsWS1 involved in cuticular wax biosynthesis is regulated by osa-miR1848

      KUAIFEI XIA, XIAOJIN OU, CHUNZHI GAO, HUADAN TANG, YONGXIA JIA, RUFANG DENG, XINLAN XU and MINGYONG ZHANG

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12576

      Does microRNA regulates wax formation in plants? OsWS1, a homolog of membrane-bound O-acyltransferase, involved in wax biosynthesis of rice, especially in elongation of very long chain fatty acids, is regulated by osa-miR1848 in development and in response to drought.

    17. Subunits B′γ and B′ζ of protein phosphatase 2A regulate photo-oxidative stress responses and growth in Arabidopsis thaliana

      GRZEGORZ KONERT, MOONA RAHIKAINEN, ANDREA TROTTA, GUIDO DURIAN, JARKKO SALOJÄRVI, SERGEY KHOROBRYKH, ESA TYYSTJÄRVI and SAIJALIISA KANGASJÄRVI

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12575

      Plant's ability to optimize their stress reactions, development and growth forms a major contributor to plant productivity, and a key question still to be resolved in plant science. Post-translational regulation by Protein Phosphatase 2A (PP2A) has recently proven vital in governing oxidative stress responses and pathogenesis reactions in Arabidopsis. Here we show that specific PP2A regulatory subunits B'γ and B'ζ are required for optimal growth under favorable conditions. Using light stress as an experimental tool, PP2A-B'γ and PP2A-B'ζ are additionally proven critical in directing the choice between cell death and acclimation, depending on the type and severity of the prevailing environmental stress.

    18. Quantifying the dynamics of light tolerance in Arabidopsis plants during ontogenesis

      FABRICIO E. L. CARVALHO, MAXWELL A. WARE and ALEXANDER V. RUBAN

      Article first published online: 14 JUL 2015 | DOI: 10.1111/pce.12574

      We quantified the capacity of plants to tolerate high light exposure during ontogenesis. Non-photochemical chlorophyll fluorescence quenching was found to be the key protective process against photoinactivation of photosystem II reaction centers. The accumulation of anthocyanins was not related to the light tolerance of the photosystem II reaction centers. The anthocyanin concentration correlated well with the concentration of hydrogen peroxide, suggesting their potential antioxidant function.

    19. Silencing a key gene of the common symbiosis pathway in Nicotiana attenuata specifically impairs arbuscular mycorrhizal infection without influencing the root-associated microbiome or plant growth

      KARIN GROTEN, ALI NAWAZ, NAM H. T. NGUYEN, RAKESH SANTHANAM and IAN T. BALDWIN

      Article first published online: 7 JUL 2015 | DOI: 10.1111/pce.12561

      While the biochemical function of calcium and calmodulin-dependent protein kinase (CCaMK) is well studied, and plants impaired in the expression of CCaMK are known not to be infected by arbuscular mycorrhizal fungi (AMF), the whole-plant and ecological consequences of CCaMK silencing are not well understood. Here we show that growth and fitness of three independently transformed lines of Nicotiana attenuata plants silenced in CCaMK (irCCaMK) and empty vector (EV) plants were similar in the glasshouse and the field. Except for AMF colonization, the overall fungal community of field-grown roots did not differ significantly among empty vector and the transgenic lines, and the bacterial communities only showed minor differences. Based on these results we conclude that silencing of CCaMK has few, if any, non-target effects.

    20. Hydrogen isotope response to changing salinity and rainfall in Australian mangroves

      S. NEMIAH LADD and JULIAN P. SACHS

      Article first published online: 3 JUL 2015 | DOI: 10.1111/pce.12579

      Salinity dependent hydrogen isotope fractionation by mangroves presents a new tool for reconstructing water salinity and rainfall rates in the past. The physiological mechanisms responsible for this relationship were investigated by measuring hydrogen isotope ratios of leaf lipids, and leaf, xylem, and surface water from three mangrove species with different salt management strategies at weekly intervals over 9.5 months in a highly seasonal estuarine bay in northeast New South Wales, Australia. Greater 2 H (deuterium) discrimination with increasing salinity characterized all studied species, with substantial variability in the magnitude of this effect among species. Leaf and xylem water isotopes indicate that biochemical responses to salt stress and/or the timing of lipid production are the likely causes of variations in hydrogen isotope fractionation both between mangrove species at the same salinity, and within a species at different salinities.

    21. ETHYLENE RESPONSE FACTOR 96 positively regulates Arabidopsis resistance to necrotrophic pathogens by direct binding to GCC elements of jasmonate – and ethylene-responsive defence genes

      JÉRÉMY CATINOT, JING-BO HUANG, PIN-YAO HUANG, MIN-YUAN TSENG, YING-LAN CHEN, SHIN-YUAN GU, WAN-SHENG LO, LONG-CHI WANG, YET-RAN CHEN and LAURENT ZIMMERLI

      Article first published online: 3 JUL 2015 | DOI: 10.1111/pce.12583

      This work describes the function of the transcription factor ERF96 in Arabidopsis thaliana immunity. Over-expression of ERF96 resulted in enhanced resistance to necrotrophic fungal and bacterial pathogens. Transcriptome and ChIP-PCR analyses indicated that the activator of transcription ERF96 directly regulates pathogen-responsive defence genes and the transcription factor ORA59. These findings revealed ERF96 as a novel modulator of the Arabidopsis immunity network.

    22. Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves

      ÜLO NIINEMETS, ZHIHONG SUN and EERO TALTS

      Article first published online: 30 JUN 2015 | DOI: 10.1111/pce.12582

      Isoprene emission rate under light-limited conditions is driven by the availability of the end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP). Apart from isoprene emission, prenyltransferase reactions leading to synthesis of photosynthetic pigments can reduce DMADP pool size, but the implications of such a possible competition on the isoprene emission light response were unknown. We demonstrated that DMADP available for isoprene synthesis increased through leaf development and aging in aspen, and this was associated with increases in the quantum yield and reduced saturation light of isoprene emission, indicating that age-dependent changes in DMADP consumption by competing sinks importantly alter the light response of isoprene release.

    23. New prenyllipid metabolites identified in Arabidopsis during photo-oxidative stress

      JOLANTA DŁUŻEWSKA, KAMIL ZIELIŃSKI, BEATRYCZE NOWICKA, RENATA SZYMAŃSKA and JERZY KRUK

      Article first published online: 30 JUN 2015 | DOI: 10.1111/pce.12580

      The aim of the study was to investigate possible new prenyllipid metabolites formed during high light stress in A rabidopsis thaliana and analyze correlation of genes expression involved in prenyllipid biosynthesis with the level of prenyllipids. It was found that plastoquinone-C accumulates mainly in the reduced form under high light conditions, as well as during short-term excess light illumination. Plastoquinone-B, an fatty acid ester of plastoquinone-C, was identified for the first time in A rabidopsis in high light grown plants and during short-time, excess light illumination. The gene expression analysis showed that vte2 gene is most pronouncedly up-regulated among the prenyllipid biosynthetic genes under high light and induction of its expression is mainly caused by an increased level of singlet oxygen.

    24. Modelling non-steady-state isotope enrichment of leaf water in a gas-exchange cuvette environment

      XIN SONG, KEVIN A. SIMONIN, KAREN E. LOUCOS and MARGARET M. BARBOUR

      Article first published online: 30 JUN 2015 | DOI: 10.1111/pce.12571

      There is an increasing popularity among plant ecophysiologists to use a gas-exchange system coupled to laser-based isotope measurement for investigating non-steady state (NSS) isotopic variability in leaf water (and/or transpiration); however, the current Farquhar & Cernusak (F&C) NSS leaf water model is unsuited for use in a gas-exchange cuvette environment due to its implicit assumption of isotope composition of water vapor (δv) being constant and independent of that of transpiration (δE). In the present study, we modified the F&C model to make it compatible with the dynamic relationship between δv and δE as is typically associated with a cuvette setting. Using an experiment conducted on cotton leaves, we show that the modified NSS model performed well in predicting the time constant for the exponential approach of leaf water toward steady state under cuvette conditions. Such a result demonstrates the applicability of this new model to gas-exchange cuvette conditions where the transpiration flux directly influences δv, and therefore suggests the need to incorporate this model into future isotope studies that employ a laser-cuvette coupled system.

    25. Improved method for measuring the apparent CO2 photocompensation point resolves the impact of multiple internal conductances to CO2 to net gas exchange

      BERKLEY J. WALKER and DONALD R. ORT

      Article first published online: 30 JUN 2015 | DOI: 10.1111/pce.12562

      There is growing interest in accurate and comparable measurements of the CO 2 photocompensation point (Γ*), a vital parameter to model leaf photosynthesis. We present a new analysis technique and measuring protocol that minimizes many errors associated with this measurement. This protocol has both a modeled and measured improvement over past methods.

  3. Reviews

    1. An Excel tool for deriving key photosynthetic parameters from combined gas exchange and chlorophyll fluorescence: theory and practice

      CHANDRA BELLASIO, DAVID J BEERLING and HOWARD GRIFFITHS

      Article first published online: 30 JUN 2015 | DOI: 10.1111/pce.12560

      We review the theory of gas exchange data analysis and present a freely downloadable Excel-based fitting tool (EFT) to derive a comprehensive suite of physiological parameters. These allow detailed comparison of photosynthetic characteristics to be made, for natural vegetation, plants with engineered photosynthetic traits, or to distinguish between C3, C4, C2, or intermediate metabolism. We include a practical example, a detailed gas-exchange protocol and a link to a video tutorial.

  4. Original Articles

    1. Balancing the risks of hydraulic failure and carbon starvation: a twig scale analysis in declining Scots pine

      YANN SALMON, JOSÉ M. TORRES-RUIZ, RAFAEL POYATOS, JORDI MARTINEZ-VILALTA, PATRICK MEIR, HERVÉ COCHARD and MAURIZIO MENCUCCINI

      Article first published online: 27 JUN 2015 | DOI: 10.1111/pce.12572

      Understanding the physiological responses of leaves to drought is crucial since they are the site of both photosynthesis and transpiration, and hence play key roles in balancing the risks of carbon starvation and hydraulic failure. Co-occurring healthy and unhealthy Scots pines showed different responses to summer drought: while healthy trees showed a typical response to drought for an isohydric species, atypical physiology in unhealthy trees appears to be driven by the need to maintain carbohydrate availability in needles and twigs. These responses put unhealthy trees at higher risk of branch hydraulic failure and help to explain the interaction between carbon-starvation and hydraulic failure in dying trees.

  5. Opinion

    1. You have full text access to this OnlineOpen article
      The many meanings of gross photosynthesis and their implication for photosynthesis research from leaf to globe

      GEORG WOHLFAHRT and LIANHONG GU

      Article first published online: 25 JUN 2015 | DOI: 10.1111/pce.12569

      • (1) 
        Gross photosynthesis is a key term in plant biology and carbon cycle science, however has been used with different meanings by different communities
      • (2) 
        We review the history of this term and associated concepts to clarify the terminology and make recommendations about a consistent use of terms in accordance with photosynthetic theory.
      • (3) 
        We show that a widely used eddy covariance CO2 flux partitioning approach yields estimates which are quantitatively closer to the definition of true photosynthesis despite aiming at estimating apparent photosynthesis.
  6. Original Articles

    1. 13CO2/12CO2 exchange fluxes in a clamp-on leaf cuvette: disentangling artefacts and flux components

      XIAO YING GONG, RUDI SCHäUFELE, WOLFGANG FENEIS and HANS SCHNYDER

      Article first published online: 25 JUN 2015 | DOI: 10.1111/pce.12564

      Leaks and isotopic disequilibria represent potential errors and artifacts during combined measurements of gas exchange and carbon isotope discrimination (Δ). This paper presents new protocols to quantify, minimize, and correct such phenomena. Leak artifacts were corrected fully by using leak coefficients of CO2, 12CO2, and 13CO2 measured with intact leaves. Assessment of isotopic disequilibria between net photosynthesis and dark respiration rate in light enabled the partitioning of the two fluxes and estimation of Δ during (net) photosynthesis.

    2. A comparison of two methods for measuring vessel length in woody plants

      RUIHUA PAN, JING GENG, JING CAI and MELVIN T. TYREE

      Article first published online: 18 JUN 2015 | DOI: 10.1111/pce.12566

      Vessels members have evolved from tracheids in ways to enhance hydraulic efficiency; members have become shorter and larger in diameter, and vessels have evolved from linear files of vessel members connected by end-walls with comparatively little obstruction to flow (scalariform perforation plates) or no obstructions (simple perforation plates), which again enhance hydraulic efficiency. Vessels have to be finite length (0.01 to 1 m) for safety against cavitation in order to confine embolisms that result from cavitation to a very small percentage of the xylem system. Their length has become important with regard to recent controversies over artifacts in cavitron measurements of vulnerability to cavitation, which has made vessel length distribution measurement important and relevant for the PCE community.

    3. Arabidopsis thaliana CML25 mediates the Ca2+ regulation of K+ transmembrane trafficking during pollen germination and tube elongation

      SHUANG-SHUANG WANG, WEN-ZHU DIAO, XUE YANG, ZHU QIAO, MEI WANG, BISWA R. ACHARYA and WEI ZHANG

      Article first published online: 18 JUN 2015 | DOI: 10.1111/pce.12559

      Ca2+ is a ubiquitous secondary messenger and plays an essential role in regulation of pollen grain germination and pollen tube elongation, but the fundamental regulatory network downstream still remains largely unknown. In this study, the Arabidopsis CML25 (Calmodulin-Like protein 25), a member of predicated Ca2+ sensor family, was found to be involved in cytosolic Ca2+ regulation of K+ influx of pollen grains and pollen tubes, and subsequently to regulate pollen grain germination, pollen tube growth and seed setting rate positively. The physiological roles and the molecular mechanisms of CML25 in pollen grains and pollen tubes uncovers a new signal pathway downstream of Ca2+ signal.

    4. Rapid responses of mesophyll conductance to changes of CO2 concentration, temperature and irradiance are affected by N supplements in rice

      DONGLIANG XIONG, XI LIU, LIMIN LIU, CYRIL DOUTHE, YONG LI, SHAOBING PENG and JIANLIANG HUANG

      Article first published online: 18 JUN 2015 | DOI: 10.1111/pce.12558

      The effects of nitrogen supplement on mesophyll conductance and its response to rapid environmental changes are poorly known. This study demonstrated a profound impact of nitrogen supplement on mesophyll conductance and its response to rapidly changing CO2 concentration, temperature and light in rice leaves. The improved mesophyll conductance under high nitrogen supplement condition attributed to the changes of leaf structure and aquaporin. Our results also highlighted the importance role of aquaporin in mesophyll conductance response to environmental changes.

    5. H+-pyrophosphatase from Salicornia europaea confers tolerance to simultaneously occurring salt stress and nitrogen deficiency in Arabidopsis and wheat

      SULIAN LV, PING JIANG, LINGLING NIE, XIANYANG CHEN, FANG TAI, DUOLIYA WANG, PENGXIANG FAN, JUANJUAN FENG, HEXIGEDULENG BAO, JINHUI WANG and YINXIN LI

      Article first published online: 11 JUN 2015 | DOI: 10.1111/pce.12557

      High salinity and nitrogen (N) deficiency which usually occur simultaneously in soil are two key factors limiting crop productivity. Here we firstly found that H+-pyrophosphatase (H+-PPase) is involved in salt stimulated NO3 uptake in the euhalophyte Salicornia europaea, and up-regulation of H+-pyrophosphatase confers tolerance to simultaneously occurring salt stress and nitrogen deficiency in Arabidopsis and wheat. This work provides alternative strategy for improving crop yields challenged by increasing soil salinization and shrinking farmland via H+-PPase regulation.

    6. You have full text access to this OnlineOpen article
      Onset of photosynthesis in spring speeds up monoterpene synthesis and leads to emission bursts

      J. AALTO, A. PORCAR-CASTELL, J. ATHERTON, P. KOLARI, T. POHJA, P. HARI, E. NIKINMAA, T. PETÄJÄ and J. BÄCK

      Article first published online: 11 JUN 2015 | DOI: 10.1111/pce.12550

      Emissions of biogenic volatile organic compounds (BVOC) by boreal evergreen trees have strong seasonality. We measured high emission peaks from Scots pine shoots caused by enhanced monoterpene synthesis taking place simultaneously with the photosynthetic spring recovery. We conclude that the increased emissions were related to the photosynthetic recovery, when the efficiency of photosynthetic carbon reactions is low whereas the light harvesting machinery actively absorbs light energy. Increased emissions may serve a protective functional role for the foliage during the transitory state, and these high emission peaks may contribute to atmospheric chemistry in the boreal forest in springtime.

    7. Seasonal and within-canopy variation in shoot-scale resource-use efficiency trade-offs in a Norway spruce stand

      LASSE TARVAINEN, MATS RÄNTFORS and GÖRAN WALLIN

      Article first published online: 11 JUN 2015 | DOI: 10.1111/pce.12565

      Resource use efficiency (RUE) is a key trait in determining the ability of plants to assimilate carbon. We demonstrate that the use efficiencies of light, water and nitrogen in determining the shoot-scale carbon uptake peak at different times of the year in a Norway spruce canopy, but also that the RUE interaction becomes increasingly dominated by light use efficiency with canopy depth at all times of the year. These temporal and spatial patterns in RUE interactions may have important implications for within-canopy resource allocation and for RUE-based modelling of canopy-scale carbon uptake. The study was based on continuous half-hourly gas exchange measurements conducted over a period of three years along a vertical canopy gradient in a mature Norway spruce stand.

    8. Examining the response of needle carbohydrates from Siberian larch trees to climate using compound-specific δ13C and concentration analyses

      K. T. RINNE, M. SAURER, A. V. KIRDYANOV, M. V. BRYUKHANOVA, A. S. PROKUSHKIN, O. V. CHURAKOVA (SIDOROVA) and R. T. W. SIEGWOLF

      Article first published online: 10 JUN 2015 | DOI: 10.1111/pce.12554

      Little is known about the dynamics of individual carbohydrates in leaves in response to climatic and physiological factors. Our study provides the first comparison of compound-specific δ13C and concentration analysis of leaf sugars combined with xylogenesis phases of tree ring formation. It uncovers how physiological and environmental factors, e.g. water availability and temperature, drive concentration and δ13C variability and uses this knowledge to identify mechanisms underlying the δ13C signals of trees. Our study provides the first in depth characterization of compound-specific needle carbohydrate variability, identifies involved mechanisms and shows the potential of such results for linking tree physiological responses to climate change.

    9. Laccaria bicolor aquaporin LbAQP1 is required for Hartig net development in trembling aspen (Populus tremuloides)

      ALFONSO NAVARRO-RÓDENAS, HAO XU, MINNA KEMPPAINEN, ALEJANDRO G. PARDO and JANUSZ J. ZWIAZEK

      Article first published online: 10 JUN 2015 | DOI: 10.1111/pce.12552

      In this study, we have identified the relationship between expression patterns of Laccaria bicolor aquaporin LbAQP1 and the development of ectomycorrhizal structures in trembling aspen (Populus tremuloides) seedlings. We have also determined that this aquaporin facilitated NO, H2O2 and CO2 transport when heterologously expressed in yeast. The report demonstrates that the Laccaria bicolor aquaporin LbAQP1 acts as a molecular signaling channel, which is fundamental for the development of Hartig net in root tips of Populus tremuloides.

    10. Rice FLAVIN-BINDING, KELCH REPEAT, F-BOX 1 (OsFKF1) promotes flowering independent of photoperiod

      SU-HYUN HAN, SOO-CHEUL YOO, BYOUNG-DOO LEE, GYNHEUNG AN and NAM-CHON PAEK

      Article first published online: 10 JUN 2015 | DOI: 10.1111/pce.12549

      The F-box protein FLAVIN-BINDING, KELCH REPEAT, FBOX 1 (FKF1) acts as a long day-dependent floral inducer by positively regulating CONSTANS at both the transcriptional and post-translational levels in Arabidopsis. However, the regulatory role of rice FKF1 (OsFKF1) in flowering time remains elusive. Here we show that OsFKF1 acts as an autonomous floral activator independent of photoperiod by modulating the expression of the rice-specific flowering-time genes, Ehd2, Ghd7, and Ehd1.

    11. Tobacco guard cells fix CO2 by both Rubisco and PEPcase while sucrose acts as a substrate during light-induced stomatal opening

      DANILO M. DALOSO, WERNER C. ANTUNES, DANIELA P. PINHEIRO, JARDEL P. WAQUIM, WAGNER L. ARAÚJO, MARCELO E. LOUREIRO, ALISDAIR R. FERNIE and THOMAS C. R. WILLIAMS

      Article first published online: 4 JUN 2015 | DOI: 10.1111/pce.12555

      Although signaling pathways in guard cells have been the subject of extensive investigation, several important questions regarding the metabolism of these cells remain unanswered. Here, we provide evidence that sucrose act as substrate during light induced stomatal opening and suggest that the carbon released is probably used for organic acid production. Furthermore, an isotope labeling experiment reveals that CO2 fixation occurs both via RubisCO and PEPcase in guard cells.

    12. Assessing potato tuber diel growth by means of X-ray computed tomography

      EDUARDO PÉREZ-TORRES, NORBERT KIRCHGESSNER, JOHANNES PFEIFER and ACHIM WALTER

      Article first published online: 4 JUN 2015 | DOI: 10.1111/pce.12548

      The manuscript deals with the use of X-ray computed tomography in the determination of potato tuber growth, its advantages compared to previous experimental approaches on the subject and novel findings derived from the use of this methodology. Results described in this manuscript have potential uses not only in potato research, but also in the study of growth and development of belowground organs in other plants, an exciting area of science where there is still much to be studied.

    13. T-DNA insertion in aquaporin gene AtPIP1;2 generates transcription profiles reminiscent of a low CO2 response

      ANASTASSIA BOUDICHEVSKAIA, MARLIES HECKWOLF and RALF KALDENHOFF

      Article first published online: 4 JUN 2015 | DOI: 10.1111/pce.12547

      The results from a transcriptome analysis of an Arabidopsis thaliana T-DNA insertion mutant line provide evidence that the product of the respective gene AtPIP1;2 caused an answer related to a limitation of CO2 diffusion. To our opinion, it provides an important argument to the ongoing debate about the significance of these kinds of aquaporins: whether the protein is a component of drought stress management or facilitates CO2 diffusion.

    14. Metabolic and transcriptomic signatures of rice floral organs reveal sugar starvation as a factor in reproductive failure under heat and drought stress

      XIA LI, LOVELY M. F. LAWAS, RICHARD MALO, ULRIKE GLAUBITZ, ALEXANDER ERBAN, RAMIL MAULEON, SIGRID HEUER, ELLEN ZUTHER, JOACHIM KOPKA, DIRK K. HINCHA and KRISHNA S. V. JAGADISH

      Article first published online: 19 MAY 2015 | DOI: 10.1111/pce.12545

      A novel attempt was made to associate temporal and spatial dynamics with the transcriptome and the metabolome of the anther, pistil before pollination and pollinated pistil exposed to heat or combined drought and heat stress, with key physiological processes determining stress induced spikelet sterility. Our work identifies key constitutive metabolite markers specific to reproductive organs that could be extremely valuable particularly with constrains associated with infrastructural challenges for precision stress phenotyping. We demonstrate that the tolerant cultivar N22 having the potential to avoid carbon starvation through e.g. the operation of sugar transporters and a cell wall invertase to reduce the impact of heat or drought stress on anthers, unlike the susceptible cultivar Moroberekan.

    15. Expression of Caenorhabditis elegansPCS in the AtPCS1-deficient Arabidopsis thalianacad1-3 mutant separates the metal tolerance and non-host resistance functions of phytochelatin synthases

      TANJA KÜHNLENZ, LORE WESTPHAL, HOLGER SCHMIDT, DIERK SCHEEL and STEPHAN CLEMENS

      Article first published online: 19 MAY 2015 | DOI: 10.1111/pce.12534

      Phytochelatin synthases have been implicated in two seemingly unrelated biological functions, toxic metal tolerance and innate immunity. We tested whether the two functions can be separated by expressing a non-plant phytochelatin synthase in a respective Arabidopsis thaliana mutant. Our results demonstrate a role of phytochelatin synthases in resistance against the nonhost pathogen Phytophthora infestans and show that this function is apparently unrelated to phytochelatin synthesis.

    16. Growth rate hypothesis and efficiency of protein synthesis under different sulphate concentrations in two green algae

      MARIO GIORDANO, MATTEO PALMUCCI and JOHN A. RAVEN

      Article first published online: 19 MAY 2015 | DOI: 10.1111/pce.12551

      • The Growth Rate Hypothesis (GRH) predicts a positive correlation between growth rate and RNA content, because growth depends on the protein synthesis machinery.
      • The application of this hypothesis to photoautotrophic organisms has been questioned.
      • Our results indicate that the GRH is valid for the prasinophycean Tetraselmis suecica and the chlorophycean Dunaliella salina, when growth rates were below 0.82 d−1.
      • Interestingly, the peptide elongation rate per ribosome is affected by the sulfate concentration in the growth media.
  7. Commentary

  8. Original Articles

    1. The heterotrimeric G-protein β subunit, AGB1, plays multiple roles in the Arabidopsis salinity response

      YUNQING YU and SARAH M. ASSMANN

      Article first published online: 12 MAY 2015 | DOI: 10.1111/pce.12542

      Salinity, one of the major problems affecting plant growth and crop yield, is a multi-trait stress that includes both osmotic and ionic toxicity. The knockout mutant of the sole Arabidopsis heterotrimeric G-protein Gβ subunit, agb1, is hypersensitive to salt stress. Here, using phenotypic analyses, gas exchange studies, ICP-AES measurements of ion content and 24Na+ flux experiments, we show that AGB1 is mainly involved in the ionic toxicity component of salinity stress and plays roles in multiple processes of Na+ homeostasis including control of root to shoot translocation of Na+ via the transpiration stream and regulation of net Na+ uptake into the root. These results provide new insights into the G protein regulatory pathways underlying plant responses to salinity.

    2. Proteomic analysis provides new insights into the adaptive response of a dinoflagellate Prorocentrum donghaiense to changing ambient nitrogen

      YING-JIAO ZHANG, SHU-FEI ZHANG, ZHI-PING HE, LIN LIN and DA-ZHI WANG

      Article first published online: 12 MAY 2015 | DOI: 10.1111/pce.12538

      We investigated proteomic response of a dinoflagellate Proroentrum donghaiense to changing ambient nitrogen (N). In response to N depletion, proteins involved in photosynthesis, carbon fixation, protein and lipid synthesis were down-regulated, while proteins participating in N reallocation and transport activity were up-regulated in N-deplete cells. Our results show that P. donghaiense possessed a specific ability, in contrast with other photosynthetic eukaryotic algae, to regulate intracellular carbon and N metabolism in response to extreme ambient N deficiency, which might be an important reason resulting in its frequent and extensive blooms in coastal waters.

    3. New insights into an RNAi approach for plant defence against piercing-sucking and stem-borer insect pests

      HAICHAO LI, RUOBING GUAN, HUIMIN GUO and XUEXIA MIAO

      Article first published online: 12 MAY 2015 | DOI: 10.1111/pce.12546

      • • 
        We demonstrated that dsRNAs can be absorbed by crop roots, trigger plant and insect RNAi.
      • • 
        Plant roots dsRNA-soaking can be used as a bioinsecticide strategy during crop irrigation.
      • • 
        The dsRNA was stable under outdoor conditions.
    4. Contributions of photosynthetic and non-photosynthetic cell types to leaf respiration in Vicia faba L. and their responses to growth temperature

      BENEDICT M. LONG, NUR H. A. BAHAR and OWEN K. ATKIN

      Article first published online: 12 MAY 2015 | DOI: 10.1111/pce.12544

      The respiratory contribution of different cell types to overall leaf respiration is largely unknown. We measured the respiratory capabilities of both mesophyll and epidermal cell protoplasts from Vicia faba L. under warm and cold growth conditions, revealing a capacity for both cytochrome and alternative oxidase activity in both protoplast types. We found that while the contribution of mesophyll cells to overall leaf respiration is dominant, epidermal cells make a small but significant (4–7%) contribution which increases in the cold. Our results confirm the heterogeneous nature of mitochondrial populations within the leaf.

    5. Force–displacement measurements of earlywood bordered pits using a mesomechanical tester

      SAMUEL L. ZELINKA, KEITH J. BOURNE, JOHN C. HERMANSON, SAMUEL V. GLASS, ADRIANA COSTA and ALEX C. WIEDENHOEFT

      Article first published online: 29 APR 2015 | DOI: 10.1111/pce.12532

      The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms. This work presents a new approach for improving the understanding the mechanics of bordered pits wherein the torus of the bordered pit is moved with an instrumented quartz micropipette. Preliminary data of the force displacement curves taken on circular bordered pits are presented.

    6. Rice PCR1 influences grain weight and Zn accumulation in grains

      WON-YONG SONG, HYUN-SOOK LEE, SANG-RAK JIN, DONGHWI KO, ENRICO MARTINOIA, YOUNGSOOK LEE, GYNHEUNG AN and SANG-NAG AHN

      Article first published online: 29 APR 2015 | DOI: 10.1111/pce.12553

      Proteins containing a placenta-specific 8 (PLAC8) domain regulate cell growth and cancer cell development in animals, fruit weight (FW2.2) in tomato, and cell number (ZmCNRs) in maize, and as putative metal ion transporters (PCRs, plant cadmium resistance) in Arabidopsis, rice, and Indian mustard. However, it has not been demonstrated how PLAC8 domain-containing proteins fulfill such diverse functions. Here, we report that rice PCR1 regulates both the Zn contents of grains and grain weight. OsPCR1 knockout and knockdown lines produced lighter grains, while OsPCR1 overexpression lines produced heavier grains than the wild type. Furthermore, the Zn and Cd contents were altered in grains of the transgenic rice lines as well as in yeast cells heterologously expressing OsPCR1. Through PCR1 sequence analysis using different rice accessions collected from many countries, we found that the PCR1s in Japonica and Indica rice exhibited distinct amino acid sequences, and this difference was associated with Zn resistance and accumulation Japonica PCR1 enhanced Zn hypersensitivity in yeast, and Japonica rice contained less Zn in their grains than did Indica rice. Our functional study and genetic analysis suggests that rice PCR1 maintains metal ion homeostasis and grain weight and might have evolved during domestication. We believe that this discovery will give great interest to the readership of Plant Cell and Environment, as it provides clues as to how PLAC8 domain-containing proteins fulfill diverse functions.

    7. Helper component-proteinase enhances the activity of 1-deoxy-D-xylulose-5-phosphate synthase and promotes the biosynthesis of plastidic isoprenoids in Potato virus Y-infected tobacco

      HENG LI, DONGYUAN MA, YONGSHENG JIN, YAYI TU, LIPING LIU, CHUNXU LENG, JIANGLI DONG and TAO WANG

      Article first published online: 27 APR 2015 | DOI: 10.1111/pce.12526

      Virus-infected plants show severe symptoms, such as chlorosis and necrosis associated with changes in chloroplast structure and function. The metabolism of various isoprenoids is also influenced concurrently. As one of the isoprenoids, the accumulations of ABA have been reported in various virus infections, but the reason for the increase is still unclear. In our study, the interaction between virus protein HC-Pro and host protein NtDXS (a limiting enzyme in MEP pathway) was proved to be a key factor. Our study revealed a new role of HC-Pro in host plants metabolism system and will contribute to the study of host-virus relationships.

  9. Commentary

  10. Original Articles

    1. FcWRKY70, a WRKY protein of Fortunella crassifolia, functions in drought tolerance and modulates putrescine synthesis by regulating arginine decarboxylase gene

      XIAOQING GONG, JINGYAN ZHANG, JIANBING HU, WEI WANG, HAO WU, QINGHUA ZHANG and JI-HONG LIU

      Article first published online: 27 APR 2015 | DOI: 10.1111/pce.12539

      • 1. FcWRKY70, a Group III WRKY gene of Fortunella crassifolia, was greatly induced by drought and abscisic acid.
      • 2. Overexpression of FcWRKY70 conferred enhanced tolerance to dehydration and drought stresses in both tobacco and lemon, which was concurrent with elevated levels of ADC (arginine decarboxylase) and putrescine.
      • 3. FcWRKY70 regulates putrescine synthesis through interacting with W-box elements in the promoter of ADC.
    2. CHX14 is a plasma membrane K-efflux transporter that regulates K+ redistribution in Arabidopsis thaliana

      JIAN ZHAO, PENGHUI LI, CHRISTY M. MOTES, SUNGHUN PARK and KENDAL D. HIRSCHI

      Article first published online: 25 APR 2015 | DOI: 10.1111/pce.12524

      K+ is an essential nutrient for plant growth and development; but K+ efflux mechanisms and K+ redistribution in plant are still poorly understood. Arabidopsis CHX14 is characterized as a plasma membrane-localized, low-affinity K+ efflux transporter. CHX14 is expressed in xylem parenchyma of root and shoot vascular tissues and induced by high concentrations of K +. It is involved in K+ recirculation and redistribution from roots to shoots to regulate K+ homeostasis and nutrition between plant tissues during K+ deficiency or under high concentration of K+.

    3. Altered levels of LIL3 isoforms in Arabidopsis lead to disturbed pigment–protein assembly and chlorophyll synthesis, chlorotic phenotype and impaired photosynthetic performance

      JENS N. LOHSCHEIDER, MARC C. ROJAS-STÜTZ, MAXI ROTHBART, ULRICA ANDERSSON, DIETMAR FUNCK, KURT MENDGEN, BERNHARD GRIMM and IWONA ADAMSKA

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12540

      The assembly of pigment-protein complexes of the thylakoid membrane during de-novo-synthesis or repair requires a tight coordination of pigment synthesis and delivery with translation. Members of the LHC-like protein family may play crucial roles in these processes. We demonstrate differential expression patterns of the two paralogous LHC-like 3 proteins (LIL3:1 and LIL3:2) under standard growth conditions and in high light treatments as well as slightly different suborganellar localisation in the thylakoid membrane. Our data show functional redundancy of the two proteins under standard growth conditions, but indicate differential functions when the plant is exposed to high light stress. In transgenic plants with altered expression of the LIL3 isoforms, thylakoid architecture, Chl synthesis and the regulation of proteins involved in tetrapyrrole synthesis are disturbed. Thus, LIL3 proteins may play an important role in retrograde signalling, orchestrating nuclear and chloroplast gene expression and translation.

    4. You have full text access to this OnlineOpen article
      Climate change alters leaf anatomy, but has no effects on volatile emissions from arctic plants

      MICHELLE SCHOLLERT, MINNA KIVIMÄENPÄÄ, HANNA M. VALOLAHTI and RIIKKA RINNAN

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12530

      The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms. This work presents a new approach for improving the understanding the mechanics of bordered pits wherein the torus of the bordered pit is moved with an instrumented quartz micropipette. Preliminary data of the force displacement curves taken on circular bordered pits are presented.

    5. Light-harvesting superstructures of green plant chloroplasts lacking photosystems

      ERICA BELGIO, PETRA UNGERER and ALEXANDER V. RUBAN

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12528

      The manuscript describes a novel and exciting combination of confocal and pulse-amplitude-modulated fluorescence, transmission and freeze-fracture electron microscopy and biochemistry approaches that analyses the structure and functions of the photosynthetic membrane highly depleted from the photosynthetic reaction center complexes, PSII in particular.

      In this manuscript we reveal that it is possible to obtain green plants that are almost totally devoid of the primary photosynthesis – their photosynthetic membranes contain no reaction centers but are greatly enriched with the light harvesting complexes. This manuscript presents a discovery of supergrana structures, discusses the causes of their formations and the evolutionary significance of the absence of the retrograde signaling pathways other than those related to redox-sensing in retaining large amounts of light harvesting membranes.

    6. You have full text access to this OnlineOpen article
      Separating water-potential induced swelling and shrinking from measured radial stem variations reveals a cambial growth and osmotic concentration signal

      TOMMY CHAN, TEEMU HÖLTTÄ, FRANK BERNINGER, HARRI MÄKINEN, PEKKA NÖJD, MAURIZIO MENCUCCINI and EERO NIKINMAA

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12541

      This paper introduces a model that separates water-potential induced changes from field-sampled dendrometer measurements, revealing a cambial growth and osmotic concentration signal. Using this signal, we investigate how environmental factors influence stem growth and tree physiology, which would otherwise be masked by water-related changes. This is important for understanding how factors affect physiological processes of the tree and developing a robust method to quantifying osmotic-related stem radial changes and stem growth.

    7. Rice cyclophilin OsCYP18-2 is translocated to the nucleus by an interaction with SKIP and enhances drought tolerance in rice and Arabidopsis

      SANG SOOK LEE, HYUN JI PARK, DAE HWA YOON, BEOM-GI KIM, JUN CHEUL AHN, SHENG LUAN and HYE SUN CHO

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12531

      This is the first report of functional analysis of PPiL1 homolog in plant. We report on rice cyclophilin OsCYP18-2, the homolog of human PPiL1, is translocated to the nucleus by an interaction with OsSKIP and regulates the stress-related and splicing factor genes mRNA expression quantatively and alternatively to cope with drought conditions as a positive transcriptional regulator.

    8. Jasmonoyl isoleucine accumulation is needed for abscisic acid build-up in roots of Arabidopsis under water stress conditions

      CARLOS DE OLLAS, VICENT ARBONA and AURELIO GÓMEZ-CADENAS

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12536

      A novel hormonal interaction in roots under water stress conditions is demonstrated. Signal transduction between water stress induced JA-Ile accumulation and COI1 is necessary for a complete early induction of the ABA biosynthesis pathway and subsequent hormone accumulation in roots of Arabidopsis plants. Although crosstalk between JA and ABA has been previously documented at the signal transduction level, we have demonstrated that jasmonates, and specifically JA-Ile, interact with ABA at the biosynthesis level under water stress conditions.

    9. AtLa1 protein initiates IRES-dependent translation of WUSCHEL mRNA and regulates the stem cell homeostasis of Arabidopsis in response to environmental hazards

      YUCHAO CUI, SHAOFEI RAO, BEIBEI CHANG, XIAOSHUANG WANG, KAIDIAN ZHANG, XUELIANG HOU, XUEYI ZHU, HAIJUN WU, ZHAOXIA TIAN, ZHONG ZHAO, CHENGWEI YANG and TAO HUANG

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12535

      Plants have to cope with the environmental hazards and safeguard stem cells which are hypersensitive to environmental hazards. The AtLa1 protein, an RNA binding factor, can bind to the 5′-untranslated region and initiates the IRES-dependent translation of WUS mRNA in the shoot apical meristem. More AtLa1 protein can be translocated from the nuclear to cytoplasm and enhance the IRES-dependent translation of WUS mRNA by exposure to environmental hazards. Then the WUS protein increases the tolerance of the shoot apical meristem to environmental hazards.

    10. You have full text access to this OnlineOpen article
      Infection of the brown alga Ectocarpus siliculosus by the oomycete Eurychasma dicksonii induces oxidative stress and halogen metabolism

      MARTINA STRITTMATTER, LAURA J. GRENVILLE-BRIGGS, LISA BREITHUT, PIETER VAN WEST, CLAIRE M. M. GACHON and FRITHJOF C. KÜPPER

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12533

      Macroalgal response to pathogen infection has mostly been studied by mimicking infection using elicitors. We have established a pathosystem between the genome model seaweed E ctocarpus siliculosus and the oomycete E urychasma dicksonii as a powerful new tool to investigate algal responses to infection via a combined approach of proteomics, qPCR and histochemial staining. Our data give an unprecedented global overview of brown algal response to pathogen infection, and highlight the importance of oxidative stress and halogen metabolism in these interactions.

    11. Freezing avoidance by supercooling in Olea europaea cultivars: the role of apoplastic water, solute content and cell wall rigidity

      NADIA S. ARIAS, SANDRA J. BUCCI, FABIAN G. SCHOLZ and GUILLERMO GOLDSTEIN

      Article first published online: 23 APR 2015 | DOI: 10.1111/pce.12529

      Biophysical and biochemical processes involved in frost avoidance were studied in five olive cultivars. Supercooling was the mechanism observed in cold acclimated plants to avoid extracellular ice formation. Differences in supercooling capacity among cultivars were associated with differences in solute content, apoplastic water content and cell wall elastic adjustments.

    12. Increased phosphate transport of Arabidopsis thaliana Pht1;1 by site-directed mutagenesis of tyrosine 312 may be attributed to the disruption of homomeric interactions

      ELENA B. FONTENOT, SANDRA FEUER DITUSA, NAOHIRO KATO, DANIELLE M. OLIVIER, RENEE DALE, WEI-YI LIN, TZYY-JEN CHIOU, MEGAN A. MACNAUGHTAN and AARON P. SMITH

      Article first published online: 17 APR 2015 | DOI: 10.1111/pce.12522

      Oligomerization has been shown to be an important aspect of regulation and function for some membrane transporters. Herein we demonstrate that the Arabidopsis Pht1;1 and Pht1;4 phosphate transporters form homomeric and heteromeric oligomers. Mutation of a tyrosine residue abolished homo-oligomerization of Pht1;1 and also conferred enhanced phosphate transport when expressed in yeast. The results suggest an active site-oligomerization relationship in which oligomerization serves as a mechanism to regulate transporter activity.

    13. Genome-wide association of drought-related and biomass traits with HapMap SNPs in Medicago truncatula

      YUN KANG, MUHAMMET SAKIROGLU, NICHOLAS KROM, JOHN STANTON-GEDDES, MINGYI WANG, YI-CHING LEE, NEVIN D. YOUNG and MICHAEL UDVARDI

      Article first published online: 17 APR 2015 | DOI: 10.1111/pce.12520

      Drought is a major impediment to maximal yield in crop plants. We performed genome-wide association analyses of eight biomass and drought-related traits in 220 M. truncatula HapMap accessions using various statistical models. For each trait, we identified candidate genes and chromosome regions containing markers that are in significant association with the trait, which could be targeted for breeding purposes to enhance crop drought tolerance.

    14. Silicon-mediated changes in polyamines participate in silicon-induced salt tolerance in Sorghum bicolor L.

      LINA YIN, SHIWEN WANG, KIYOSHI TANAKA, SHINSUKE FUJIHARA, AKIHIRO ITAI, XIPING DEN and SUIQI ZHANG

      Article first published online: 17 APR 2015 | DOI: 10.1111/pce.12521

      This study demonstrates that silicon improves salt tolerance through regulating polyamines (PAs) and ethylene levels in sorghum. The high levels of PAs maintain K+/Na+ homeostasis and moderate salt-induced senescence, leading to improved salt tolerance. These results support the idea that silicon is involved in mediating the salt tolerance response in plants.

    15. Dissecting spatiotemporal biomass accumulation in barley under different water regimes using high-throughput image analysis

      KERSTIN NEUMANN, CHRISTIAN KLUKAS, SWETLANA FRIEDEL, PABLO RISCHBECK, DIJUN CHEN, ALEXANDER ENTZIAN, NILS STEIN, ANDREAS GRANER and BENJAMIN KILIAN

      Article first published online: 14 APR 2015 | DOI: 10.1111/pce.12516

      This pilot study in barley demonstrates, that vegetative biomass accumulation, drought tolerance and ability to recover after re-watering can be reliably analyzed by non-invasive, high-throughput image-based phenotyping under greenhouse conditions. Drought stress symptoms were visualized and appropriate models uncovered growth dynamics in control and drought stress conditions. Digital traits showed a high heritability and thus represent a starting point for the genetic analysis for biomass accumulation.

    16. You have full text access to this OnlineOpen article
      Carbon partitioning in Arabidopsis thaliana is a dynamic process controlled by the plants metabolic status and its circadian clock

      KATHARINA KÖLLING, MATTHIAS THALMANN, ANTONIA MÜLLER, CAMILLA JENNY and SAMUEL C. ZEEMAN

      Article first published online: 9 APR 2015 | DOI: 10.1111/pce.12512

      This work focusses on the temporal changes in the allocation and transport of photoassimilates within Arabidopsis rosettes, helping to fill a gap in our understanding of plant growth. Using short pulses of 14C-labelled carbon dioxide, we quantified how much carbon is used for growth and how much is stored as starch for use at night. In source leaves, partitioning is surprisingly dynamic during the day, even though photosynthesis is relatively constant, while in sink leaves, utilisation is more constant. Furthermore, by analysing metabolic mutants and clock mutants, and by manipulating the growth conditions, we show that partitioning is responsive to endogenous signals such as carbon starvation and the plant's circadian rhythm.

    17. Vulnerability to cavitation differs between current-year and older xylem: non-destructive observation with a compact magnetic resonance imaging system of two deciduous diffuse-porous species

      KENJI FUKUDA, DAICHI KAWAGUCHI, TOMO AIHARA, MAYUMI Y. OGASA, NAOKO H. MIKI, TOMOYUKI HAISHI and TOSHIHIRO UMEBAYASHI

      Article first published online: 20 MAR 2015 | DOI: 10.1111/pce.12510

      Development of xylem embolism during water stress in two diffuse-porous hardwoods, Katsura (Cercidiphyllum japonicum) and Japanese white birch (Betula platyphylla var. japonica), was observed nondestructively under a compact magnetic resonance imaging (MRI) system in addition to conventional quantitation of hydraulic vulnerability to cavitation from excised stem segments. The increase in the relative embolized area estimated from the binarized MR images was consistent with the hydraulic vulnerability curves of these species. From the MRI observations, cavitation induced by water stress was shown to develop earlier in 1- or 2-year-old xylem than in the current-year xylem in the both species; i.e., the vulnerability to cavitation differs between vessels in the current-year xylem and those in older annual rings.

    18. Resilience of rice (Oryza spp.) pollen germination and tube growth to temperature stress

      ONORIODE COAST, ALISTAIR J. MURDOCH, RICHARD H. ELLIS, FIONA R. HAY and KRISHNA S.V. JAGADISH

      Article first published online: 14 FEB 2015 | DOI: 10.1111/pce.12475

      This paper explores mechanisms of tolerating short periods of high temperature stress at anthesis in rice in the context of potential climate change and also bearing in mind the wide range of agro-ecosystems in which rice is grown. The paper is the first time responses of individual pollen grains have been modelled in terms of their minimum temperature requirement and maximum temperature limit for germination. Resilience to high temperature stress at anthesis perhaps not surprisingly required a high mean maximum temperature limit for pollen germination, but less obviously, a wide standard deviation of maximum temperature limits among individual pollen grains. Moreover, the hypothesis that physiological mechanisms of tolerance to heat and cold stresses at anthesis were different, was tested and accepted.

    19. Accumulation of terpenoid phytoalexins in maize roots is associated with drought tolerance

      MARTHA M. VAUGHAN, SHAWN CHRISTENSEN, ERIC A. SCHMELZ, ALISA HUFFAKER, HEATHER J. MCAUSLANE, HANS T. ALBORN, MARITZA ROMERO, LEON HARTWELL ALLEN and PETER E. A. TEAL

      Article first published online: 23 JAN 2015 | DOI: 10.1111/pce.12482

      Terpenoid phytoalexins accumulate in maize roots with Diabrotica balteata herbivory, Fusarium verticillioides infection, drought and high salinity. Mutant an2 plants deficient in kauralexin biosynthesis are more sensitive to drought.

    20. OsAUX1 controls lateral root initiation in rice (Oryza sativa L.)

      HEMING ZHAO, TENGFEI MA, XIN WANG, YINGTIAN DENG, HAOLI MA, RONGSHENG ZHANG and JIE ZHAO

      Article first published online: 7 JAN 2015 | DOI: 10.1111/pce.12467

      In this study, we detail investigated function of OsAUX1 (LOC_Os01g63770). OsAUX1 was abundantly expressed in root tips, lateral roots and lateral root primordial, three OsAUX1 T-DNA mutants and RNAi plants exhibited a reduced number of primordia and lateral roots, and the overexpression lines exhibited an increased number of primordia and lateral roots. Analysis of IAA content detection and DR5::GUS expression suggested that there was significant reduction in auxin levels in the root tips of osaux1 mutants, and transcriptome analysis also showed that expressions of several auxin regulated genes were altered in osaux1. The results indicated that OsAUX1 was involved in polar auxin transport and controlled lateral root initiation in rice.

    21. Light intensity affects chlorophyll synthesis during greening process by metabolite signal from mitochondrial alternative oxidase in Arabidopsis

      DA-WEI ZHANG, SHU YUAN, FEI XU, FENG ZHU, MING YUAN, HUA-XUN YE, HONG-QING GUO, XIN LV, YANHAI YIN and HONG-HUI LIN

      Article first published online: 14 OCT 2014 | DOI: 10.1111/pce.12438

      Previous studies indicated that during greening, chlorophyll accumulation was largely delayed in plants whose mitochondrial cyanide-resistant respiration was inhibited by knocking out nuclear encoded alternative oxidase (AOX) gene. Here we show that this delay of chlorophyll accumulation was more significant under high light condition and mainly attributed to blocked import of plastidial enzymes, which catalyzes tetrapyrrole or phytol biosynthesis. Inhibition of cyanide-resistant respiration was also was also accompanied by the increase of plastid NADPH / NADP+ ratio, especially under high light treatment which subsequently blocked the import of multiple plastidial proteins import. It thus suggests that light intensity affects chlorophyll synthesis during greening process by a metabolic signal, the AOX-derived plastidial NADPH/NADP + ratio change.

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