Abstract
The capacity for maintenance of turgor potential (ΨP) and relative water content (ξ) were examined in 16 wheat cultivars from different habitats with different agronomic drought resistance and different photosynthetic responses to water stress. Substantial cultivar differences in ΨP and ξ maintenance were observed at all of the seedling, booting and grain filling stages. Maintenances of ΨP and ξ positively correlated with photosynthetic maintenance under water deficit conditions, suggesting that capacity of ΨP and ξ maintenance can be used as drought resistance criteria. In general, the cultivars can bring their abilities of ΨP and ξ maintenances through the whole growth period, but the abilities were higher at the grain filling stage than the earlier growth staged. With comparison of water-stress resistant cultivars, it was found that some of them could maintain higher photosynthetic activity at lower ΨP or ξ than the others. Integrated results of the present research suggest that turgor regulation and ξ maintenance play important roles in photosynthetic maintenance under low soil water potentials.
