Physiological and anatomical responses of Crambe abyssinica to repeated exposure to water deficit

Abstract

Description of the subject. It is common for cultivated plants to face a single water deficit event, but in the wild plants are exposed to repeated cycles of drought and rehydration and the consequences of such repetitive events are less well understood. Objectives. The objective of this study was to understand how crambe’s performance under water limiting conditions is affected by previous exposure to water deficit. Method. Crambe plants were grown in 5.5 l pots and exposed to one (1WD) or three (3WD) water deficit cycles. As reference, plants were grown with daily irrigation. At the end of three water deficit cycles, the leaf anatomy, leaf relative water content (RWC), stomatal conductance, extravasation of electrolytes and chlorophyll fluorescence were analyzed. Results. Under water deficit, RWC significantly decreased in 1WD plants. However, in plants of the FMS CR 1307 lineage, the application of three water deficit cycles did not change the RWC and decreased the stomatal conductance and extravasation of electrolytes compared to the reference plants. Likewise, the kinetic difference in chlorophyll fluorescence (K-band and L-band) indicated improved stability and efficiency in utilizing energy. Conclusions. Our results show that the drought stress imposed three times induced adjustments in the physiology and anatomy of crambe plants. The FMS CR 1307 lineage was better able to store information from previous stressful events than the FMS Brilhante and FMS CR 1326 lineages, showing better performance under water deficit.

Keywords

• chlorophyll a fluorescence
• drought stress
• adaptation
• drought tolerance
• stress memory
• leaf anatomy