Photosynthetic limitations and volatile and non‐volatile isoprenoids in the poikilochlorophyllous resurrection plant Xerophyta humilis during dehydration and rehydration
Open Access
- 14 May 2012
- journal article
- research article
- Published by Wiley in Plant, Cell & Environment
- Vol. 35 (12), 2061-2074
- https://doi.org/10.1111/j.1365-3040.2012.02536.x
Abstract
We investigated the photosynthetic limitations occurring during dehydration and rehydration of Xerophyta humilis, a poikilochlorophyllous resurrection plant, and whether volatile and non‐volatile isoprenoids might be involved in desiccation tolerance. Photosynthesis declined rapidly after dehydration below 85% relative water content (RWC). Raising intercellular CO2 concentrations during desiccation suggest that the main photosynthetic limitation was photochemical, affecting energy‐dependent RuBP regeneration. Imaging fluorescence confirmed that both the number of photosystem II (PSII) functional reaction centres and their efficiency were impaired under progressive dehydration, and revealed the occurrence of heterogeneous photosynthesis during desiccation, being the basal leaf area more resistant to the stress. Full recovery in photosynthetic parameters occurred on rehydration, confirming that photosynthetic limitations were fully reversible and that no permanent damage occurred. During desiccation, zeaxanthin and lutein increased only when photosynthesis had ceased, implying that these isoprenoids do not directly scavenge reactive oxygen species, but rather protect photosynthetic membranes from damage and consequent denaturation. X. humilis was found to emit isoprene, a volatile isoprenoid that acts as a membrane strengthener in plants. Isoprene emission was stimulated by drought and peaked at 80% RWC. We surmise that isoprene and non‐volatile isoprenoids cooperate in reducing membrane damage in X. humilis, isoprene being effective when desiccation is moderate while non‐volatile isoprenoids operate when water deficit is more extreme.Keywords
This publication has 84 references indexed in Scilit:
- Increased Thermostability of Thylakoid Membranes in Isoprene-Emitting Leaves Probed with Three Biophysical TechniquesPlant Physiology, 2011
- Characterization of the β-Carotene Hydroxylase Gene DSM2 Conferring Drought and Oxidative Stress Resistance by Increasing Xanthophylls and Abscisic Acid Synthesis in RicePlant Physiology, 2010
- Abiotic stresses and induced BVOCsTrends in Plant Science, 2010
- In Situ Investigation of Leaf Water Status by Portable Unilateral Nuclear Magnetic ResonancePlant Physiology, 2009
- Zeaxanthin Has Enhanced Antioxidant Capacity with Respect to All Other Xanthophylls in Arabidopsis Leaves and Functions Independent of Binding to PSII AntennaePlant Physiology, 2007
- Isoprene Emission from Plants: Why and HowAnnals of Botany, 2007
- Fitting photosynthetic carbon dioxide response curves for C3 leavesPlant, Cell & Environment, 2007
- Emissions of volatile organic compounds from cut grass and clover are enhanced during the drying processGeophysical Research Letters, 1999
- A global model of natural volatile organic compound emissionsJournal of Geophysical Research: Atmospheres, 1995
- A biochemical model of photosynthetic CO2 assimilation in leaves of C3 speciesPlanta, 1980