Stomatal density and gas exchange in six wheat cultivars

Abstract

Stomatal density (SD) and stomatal index (SI) on the abaxial flag leaf epidermis, gas exchange of flag leaves and yield of six wheat ( Triticum aestivum L.) cultivars differing in drought resistance were studied in plant growth chamber. There were significant differences among cultivars in SD, SI, epidermal cell density (ED), photosynthetic rate (P n ), transpiration rate (E), instantaneous transpiration efficiency (ITE), shoot dry weight yield (Ys), grain yield (Yd) and whole growth season water use efficiency (WUE), but not in stomatal conductance (g s ). Wheat cultivars with moderate drought resistance had higher P n and Yd than cultivars with strong or weak drought resistance. SD was negatively correlated with ITE (r=−0.85) and WUE (r=−0.84), but not with P n , E and Yd. There were significant relationships between ED and Yd (r=−0.92), between SI and P n (r=0.84). These results revealed that breeding wheat cultivar only to raise drought resistance might cause yield decrease when water stress was not t...