How does moderate drought affect quantum yield and the regulation of sugar metabolism at low temperature in durum wheat (Triticum durum l.)?

Abstract

Currently, limited knowledge is available about the combined effects of drought and light in case of cold stress. The investigation of quantum yield kinetics may help understand how plants utilize light under adverse environmental conditions. In the present study, mild drought helped preserve quantum yield in durum wheat (Triticum durum L.). The time necessary to reach the steady-state actual quantum yield corresponded with the cold sensitivity. Possible underlying mechanisms induced by drought, such as the reduction of malondialdehyde content, accumulation of D-sorbit, and glycine betaine, may have protected photosynthetic apparatus and integrity of light reactions. Low sucrose content at normal growth light might have caused stomatal closing and promoted photorespiration. In contrast to growth light, low light and moderate drought positively affected the sucrose accumulation and maintained glycolysis and energy production at low temperature. Present results emphasized the role of moderate drought as a sufficient acclimation factor against cold in durum wheat.