These authors contributed equally to the present study.
Response pattern of amino compounds in phloem and xylem of trees to soil drought depends on drought intensity and root symbiosis
Article first published online: 30 JUL 2012
© 2012 German Botanical Society and The Royal Botanical Society of the Netherlands
Special Issue: Woody Plant Performance in a Changing Climate. Guest Editor: M.S. Günthardt-Goerg. The German Botanical Society, the Royal Botanical Society of the Netherlands and Wiley have published this supplement without financial support.
Volume 15, Issue Supplement s1, pages 101–108, January 2013
How to Cite
Liu, X.-P., Gong, C.-M., Fan, Y.-Y., Eiblmeier, M., Zhao, Z., Han, G. and Rennenberg, H. (2013), Response pattern of amino compounds in phloem and xylem of trees to soil drought depends on drought intensity and root symbiosis. Plant Biology, 15: 101–108. doi: 10.1111/j.1438-8677.2012.00647.x
Editor M. Günthardt-Goerg
- Issue published online: 21 DEC 2012
- Article first published online: 30 JUL 2012
- Received: 31 January 2012; Accepted: 1 June 2012
- Amino compounds;
- drought stress;
- long-distance transport;
- nitrogen nutrition;
- symbiotic N fixation
This study aimed to identify drought-mediated differences in amino nitrogen (N) composition and content of xylem and phloem in trees having different symbiotic N2-fixing bacteria. Under controlled water availability, 1-year-old seedlings of Robinia pseudoacacia (nodules with Rhizobium), Hippophae rhamnoides (symbiosis with Frankia) and Buddleja alternifolia (no such root symbiosis) were exposed to control, medium drought and severe drought, corresponding soil water content of 70–75%, 45–50% and 30–35% of field capacity, respectively. Composition and content of amino compounds in xylem sap and phloem exudates were analysed as a measure of N nutrition. Drought strongly reduced biomass accumulation in all species, but amino N content in xylem and phloem remained unaffected only in R. pseudoacacia. In H. rhamnoides and B. alternifolia, amino N in phloem remained constant, but increased in xylem of both species in response to drought. There were differences in composition of amino compounds in xylem and phloem of the three species in response to drought. Proline concentrations in long-distance transport pathways of all three species were very low, below the limit of detection in phloem of H. rhamnoides and in phloem and xylem of B. alternifolia. Apparently, drought-mediated changes in N composition were much more connected with species-specific changes in C:N ratios. Irrespective of soil water content, the two species with root symbioses did not show similar features for the different types of symbiosis, neither in N composition nor in N content. There was no immediate correlation between symbiotic N fixation and drought-mediated changes in amino N in the transport pathways.