Variability of the photosynthetic machinery tolerance when imposed to rapidly or slowly imposed dehydration in native Mediterranean plants

Dehydration affects the photosynthetic apparatus. The impact of dehydration on photosynthesis was assessed in twelve Mediterranean species representing different growth forms. Rapid and slow dehydration experiments were conducted to (1) compare the impact of water stress among species and growth forms, (2) rank species according to their drought tolerance. Rapid dehydration reduced the electron transport up to PSI, the reduction being linearly related to leaf relative water content (RWC), except for the deciduous species. Specific energy fluxes per reaction center and maximum photochemical activity of PSII remained relatively stable until 10-30% RWC. The modification pattern of the studied parameters was similar for all the growth forms. Slow rehydration increased specific energy fluxes and decreased quantum yields. The dehydration pattern was similar among growth forms, while the recovery pattern was species-specific. Drought tolerance ranking through drought factor index was relatively modified with the integrated biomarker response method.

Automated summary

Dehydration affects photosynthesis, and experiments conducted on different Mediterranean plant species with various growth forms revealed that rapid dehydration reduces electron transport, while specific energy fluxes and maximum photochemical activity remain stable until a certain leaf water content. Slow rehydration increases energy fluxes and decreases quantum yields. Different growth forms exhibit similar dehydration patterns, while the recovery pattern is species-specific.