北疆棉花光合,蒸腾作用基本特性与测试技术的探讨

在北疆大田自然条件下，棉叶光合晴天日变化呈双峰和单峰两种形式。光合速率上午大于下午。蒸腾速率呈单峰曲线，最大值出现在温度最高的１５：００－１６：００时，打顶前主茎自上而下第１和第４完全展开叶Ｐｎ最高，打顶后第１展开叶最高；Ｔｒ在打顶前后均是第１完全展开叶为最强。

A Preliminary Probe into Characteristics and Measuring Techniques of Photosynthetic Rate and Transpiration Rate of Cotton Leaves in North Xinjiang

The characteristics of photosynthesis and transpiration of cotton leaves were studied under the meteorologcal conditions of cotton field in North Xinjiang.It was known that photosynthetic rate appeared to be a single of double peak curve Photosynthetic rate was higher in the morning than that in the afternoon.The transpiration rate appeared to be a single peak curve during the day,and the maximum value appeared at 3 p.m and 4 p.m which showing no difference of time with the maximum value of air temperature.The maximum value of leaf photosynthetic rate appeared at lst(Gossydium hirsutum L)and 4th(Gossydium barbadense)whole-expanded leaves from top to bottom on main stem before picking up tips and lst leaf after.The maximum value of leaf transpiration rate appeared at lst leaf on main stem no matter before picking up tips or after.It was found that the photosynthesis rate,transpiration rate and water use efficiency of the higher yield cotton were higher than those of the common.The photosynthetic rate and transpiration rate were decreased under soil water stress.Finally,the measuring techniques about photosynthesis and transpiration in the meteorological conditions of the cotton field in North Xinjiang were probed in this paper.