Morpho-anatomical, physiological and biochemical adjustments in response to root zone salinity stress and high solar radiation in two Mediterranean evergreen shrubs, Myrtus communis and Pistacia lentiscus

Authors

  • Massimiliano Tattini,

    1. Istituto per la Valorizzazione del Legno e delle Specie Arboree, IVALSA, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, Sesto F.no, I−50019 Firenze, Italy;
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  • Damiano Remorini,

    1. Dipartimento di Coltivazione e Difesa delle Specie Legnose ‘G. Scaramuzzi’, Università di Pisa, Via del Borghetto 80, I−56124, Pisa, Italy;
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  • Patrizia Pinelli,

    1. Dipartimento di Scienze Farmaceutiche, Università di Firenze, Via Ugo Schiff 6, Sesto F.no, I−50019 Firenze, Italy;
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  • Giovanni Agati,

    1. Istituto di Fisica Applicata ‘Nello Carrara’, IFAC, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, Sesto F.no, I−50019 Firenze, Italy
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  • Erica Saracini,

    1. Istituto per la Valorizzazione del Legno e delle Specie Arboree, IVALSA, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, Sesto F.no, I−50019 Firenze, Italy;
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  • Maria Laura Traversi,

    1. Istituto per la Valorizzazione del Legno e delle Specie Arboree, IVALSA, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, Sesto F.no, I−50019 Firenze, Italy;
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  • Rossano Massai

    1. Dipartimento di Coltivazione e Difesa delle Specie Legnose ‘G. Scaramuzzi’, Università di Pisa, Via del Borghetto 80, I−56124, Pisa, Italy;
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Author for correspondence: Massimiliano Tattini Tel: +39 0555225692 Fax: +39 0555225656 Email: tattini@ivalsa.cnr.it

Summary

  • • Salt- and light-induced changes in morpho-anatomical, physiological and biochemical traits were analysed in Myrtus communis and Pistacia lentiscus with a view to explaining their ecological distribution in the Mediterranean basin.
  • • In plants exposed to 20 or 100% solar radiation and supplied with 0 or 200 mm NaCl, measurements were conducted for ionic and water relations and photosynthetic performance, leaf morpho-anatomical and optical properties and tissue-specific accumulation of tannins and flavonoids.
  • • Net carbon gain and photosystem II (PSII) efficiency decreased less in P. lentiscus than in M. communis when exposed to salinity stress, the former having a superior ability to use Na+ and Cl for osmotic adjustment. Morpho-anatomical traits also allowed P. lentiscus to protect sensitive targets in the leaf from the combined action of salinity stress and high solar radiation to a greater degree than M. communis. Salt and light-induced increases in carbon allocated to polyphenols, particularly to flavonoids, were greater in M. communis than in P. lentiscus, and appeared to be related to leaf oxidative damage.
  • • Our data may conclusively explain the negligible distribution of M. communis in open Mediterranean areas suffering from salinity stress, and suggest a key antioxidant function of flavonoids in response to different stressful conditions.

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