Acclimation of photosynthetic apparatus to moderate drought stress in wheat varieties differing in tolerance

Abstract

Aim. Drought is one of the most harmful abiotic stresses limiting crop productivity. We study the ability of photosynthetic apparatus of winter wheat varieties differing in their tolerance to acclimate to moderate drought stress under pot experiment. Methods. Dynamics of relative water content (RWC), chlorophyll content, CO2 assimilation rate (Pn), activity of antioxidant enzymes in chloroplasts of flag leaf of drought-tolerant variety Yednist and less drought-tolerant varieties Podilska Nyva and Darunok Podillia during weeklong moderate drought at flowering and one week after resumption of optimal watering were studied. Results. RWC and chlorophyll content gradually decreased from the onset to the end of drought period. In contrast, Pn inhibition was notably stronger at the onset than at the end of the drought period in Yednist and Podilska Nyva cultivars and remained the same in Darunok Podillia cultivar. On the 7th day of post-drought period, Pn in treated plants of all varieties was restored to the control level despite significantly lower chlorophyll content. Conclusions. Photosynthetic apparatus of more tolerant variety has a greater ability to acclimate to prolonged moderate drought which was related to higher activity of antioxidant enzymes and resulted in less grain yield losses.