Photo- and antioxidative protection, and a role for salicylic acid during drought and recovery in field-grown Phillyrea angustifolia plants

Sergi Munné-Bosch, Josep Peñuelas

    Research output: Contribution to journalArticleResearchpeer-review

    225 Citations (Scopus)

    Abstract

    Mechanisms of photo- and antioxidative protection, the extent of oxidative stress, and salicylic acid accumulation in leaves of Phillyrea angustifolia L. (Oleaceae) plants exposed to drought and recovery in Mediterranean field conditions were studied. The amounts of α-tocopherol increased up to 4-fold and those of zeaxanthin increased up to 3-fold at relative leaf water contents (RWCs) of ca. 60%, which caused up to 70% increases in the de-epoxidation state of the xanthophyll cycle (DPS). While α-tocopherol increased further in severe drought, zeaxanthin levels and DPS remained constant, β-carotene decreased and malondialdehyde (MDA) levels increased at RWCs below 50%. Though this was associated with significant decreases in the maximum efficiency of photosystem II photochemistry (Fv/F m), the same leaves that suffered from drought recovered after rainfalls, and similar MDA levels and Fv/Fm ratios to those observed before drought were attained. During recovery (i) the F v/Fm ratio and β-carotene levels increased slowly, (ii) α-tocopherol levels decreased sharply, to increase again, and (iii) MDA levels in leaves increased to values 35% higher than those observed at maximum drought, and decreased later. Salicylic acid (SA) levels showed a strong negative correlation (r2 = 0.857) with the RWC, and increased progressively up to 5-fold, during drought. During recovery, SA levels decreased, but remained slightly higher than those observed before drought. SA levels were positively correlated with those of α-tocopherol during drought (r2 = 0.718), but not during recovery (r2 = 0.221). We conclude that (i) P. angustifolia plants activate several mechanisms of photo- and antioxidative protection to withstand drought stress during a Mediterranean summer, (ii) endogenous SA levels increase in leaves of drought-stressed plants, thus suggesting a role for SA in plant responses to drought, and (iii) plants suffer oxidative stress during recovery, and this stress is more severe as the previous drought is more intense.
    Original languageEnglish
    Pages (from-to)758-766
    JournalPlanta
    Volume217
    Issue number5
    DOIs
    Publication statusPublished - 1 Sep 2003

    Keywords

    • α-Tocopherol
    • Drought stress
    • Oxidative stress
    • Phillyrea
    • Photoprotection
    • Salicylic acid

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