Physiological responses to intense water deficit in two genotypes of crambe (Crambe abyssinica Hochst.)

Abstract

Drought stress is a major environmental factor limiting growth and agricultural productivity. The objective of this study was to compare photosynthetic responses to intense water deficit and the recovery capacity in crambe plants (Crambe abyssinica Hochst. cultivar FMS Brilhante and lineage FMS CR1101) using chlorophyll a fluorescence analyses. Plants were submitted to water deficit for seven days followed by rehydration. Chlorophyll a fluorescence measurements were performed using a Handy-PEA fluorometer. Under drought stress, there was a reduction of the leaf relative water content (RWC) and stomatal conductance (gs), with full recovery after three days of rehydration to BRS Brilhante cultivar. Both genotypes showed decreased flux of electrons transport from the absorption to the reduction of the intersystem acceptors. FMS Brilhante cultivar showed better energetic connectivity (L-band) between photosystem II (PSII) units and lower inactivation of the oxygen-evolving complex (K-band), evidencing advantages of the cultivar compared to FMS CR1101 lineage. Finally, the recovery of photosynthetic activity observed in FMS CR1101 lineage during rehydration was due the phenomena related to the electron flow around the PSI.