Abstract: In this report we performed a comparative study on the water use efficiency (WUE), root system hydraulic conductivity (Lpr)between the seedlings of two different wheat variety Jinmai47 and Shi4185 in adequate water condition and simulated drought stress condition. In normal water supply condition, water consumption, root dry weight, biomass per plant of Jinmai47 was lower than of Shi4185, but the water use efficiency in root (WUEr), water use efficiency in stem (WUEs), WUE per plant, root system hydraulic conductivity in the former were higher than in the later; compared to the situation in normal water supply condition in moderate drought stress condition, the root dry weight of Shi4185 increased moderately yet the root dry weight of Jinmai47 did changed, biomass of per plant of both varieties reduced, the water use efficiency in root, in stem or whole plant became higher significantly. An interesting observation in this stress condition was that the water use efficiency in root of variety Shi4185 was higher than of Jinmai47.root system hydraulic conductivity in both varieties reduced and in Jinmai47 reduced more in degree than in Shi4185 resulting in a lower root system hydraulic conductivity in Jinmai47 than in Shi4185. These results showed that: in adequate water supply condition, Jinmai47 used water wasteful yet facing drought stress it could reduce transpiration to save water resulting in survival of plant on the earth; in adequate water supply condition, Shi4185 consumed a lot of water while in drought stress condition it used water more efficiently more ever the water use efficiency in root increased significantly suggesting it could enlarge its root system to absorb water responsing to drought stress compared with to which in normal water supply condition. In summary, our study indicated that the root system plays an critical role in drought stress response of wheat and the different root systems of different varieties response differently to drought stress.

Key words: Water stress, Winter wheat, Water use efficiency(WUE), Root hydraulic conductivity(Lpr)

CLC Number: 

• S512.01