棉花叶片水分利用效率及其影响因素的研究

Studies on Water Use Efficiency of Cotton Leaves and Its Relationswith Environment Factors

在北疆棉区田间自然条件下对棉叶水分利用效率（ＷＵＥ）及其影响因素的研究表明，（１）棉叶ＷＵＥ日变化呈多峰型，最低谷出现在午后光合午休及蒸腾作用最旺盛的１５－１７时。（２）棉花生育后期，叶片ＷＵＥ随主茎叶片自上而下降低，但上部叶片变幅较小，同时随生育时期推延、叶片衰老而降低。（３）高产棉田ＷＵＥ比普通棉田高。（４）由于基因型间叶片ＷＵＥ存在显著的差异以及ＷＵＥ与光合速率的关系比与蒸腾速率更密切，因此，通过育种途径或栽培措施增加棉叶光合速率是提高ＷＵＥ的关键。

The water use efficiency (WUE ) of cotton leaves under the meteological condi- tions of cotton field in north Xinjiang was studied. The results showed that : ( 1)The diurnal variation of leaf WUE appeared to be a multi -peak curve. The lowest value appeared at 15 - 17pm , which was at the same time with photosynthesis mid -nap and strongly transpirat- ing. (2)With leaf positions decreasing on main stem and leaf growing old , WUE decreased , but there were little differences for WUE among upper leaf positions. (3 )The WUE of cot- ton leaf in high yield field was higher than that in common field. (4)The present results sug- gested that selecting high, photosynthetic rate (Pn ) genotypes and .increasing Pn by cultiva- tion measures could be critical ways to increase WUE of cotton leaf.