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Photosynthetic performance and biochemical adjustments in two co-occurring Mediterranean evergreens, Quercus ilex and Arbutus unedo, differing in salt-exclusion ability

TitlePhotosynthetic performance and biochemical adjustments in two co-occurring Mediterranean evergreens, Quercus ilex and Arbutus unedo, differing in salt-exclusion ability
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2014
AuthorsFusaro, L., Mereu S., Brunetti C., Di Ferdinando M., Ferrini F., Manes F., Salvatori Elisabetta, Marzuoli R., Gerosa G., and Tattini M.
JournalFunctional Plant Biology
Volume41
Pagination391-400
ISSN14454408
KeywordsAntioxidant, gas exchange, leaf morphology, Salinity, shoot, Stomatal conductance, transpiration, tree, water stress
Abstract

The responses to mild root zone salinity stress were investigated in two co-occurring Mediterranean woody evergreens, Quercus ilex L. and Arbutus unedo L., which differ in morpho-anatomical traits and strategies to cope with water deficit. The aim was to explore their strategies to allocate potentially toxic ions at organism level, and the consequential physiological and biochemical adjustments. Water and ionic relations, gas exchange and PSII performance, the concentration of photosynthetic pigments, and the activity of antioxidant defences, were measured. Q. ilex displayed a greater capacity to exclude Na + and Cl-from the leaf than A. unedo, in part as a consequence of greater reductions in transpiration rates. Salt-induced reductions in CO 2 assimilation resulted in Q. ilex suffering from excess of light to a greater extent than A. unedo. Consistently, in Q. ilex effective mechanisms of nonphotochemical quenching, also sustained by the lutein epoxide-lutein cycle, operated in response to salinity stress. Q. ilex also displayed a superior capacity to detoxify reactive oxygen species (ROS) than A. unedo. Our data suggest that the ability to exclude salt from actively growing shoot organs depends on the metabolic cost of sustaining leaf construction, i.e. species-specific leaf life-span, and the relative strategies to cope with salt-induced water stress. We discuss how contrasting abilities to restrict the entry and transport of salt in sensitive organs relates with species-specific salt tolerance.

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URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-84896323363&doi=10.1071%2fFP13241&partnerID=40&md5=e21dfae59967f99eade87941b54f4fca
DOI10.1071/FP13241
Citation KeyFusaro2014391