土壤水分对异株荨麻光合作用的影响

Effect of Soil Moisture on Photosynthesis of Urtica dioica L.

采用盆栽和人工控制土壤水分的方法,使用LI6400便携式光合测定系统观测了5种土壤水分条件下异株荨麻光合生理生态特征的日变化。结果表明:在不同土壤水分状况下,异株荨麻净光合速率日变化曲线均呈"双峰"型,并有不同程度的"午休"现象,随着土壤水分的升高,最高值从下午17:00提前到上午的9:00;蒸腾速率和气孔导度日变化具有较好的协同性,也呈"双峰"型,大小顺序依次为T3处理>T2处理>T1处理>T4处理>T5处理;水分利用效率最高值出现在上午较早的时段,且上午的水分利用效率明显高于下午。

Under pot planting and water controlling condition,the diurnal variations of photosynthetic characteristics of Urtica dioica L.were measured under 5 different soil water conditions using Li26400 portable photosynthesis system.The results showed that the diurnal course of net photosynthetic rate was displayed in a two peak pattern with a typical midday depression pattern under different drought stress.The maximum value of net photosynthetic rate appeared from 17：00 to 9：00 with the increase of soil moisture.Coordination existed Between daily change process of transpiration rate and daily change process of stomatal conductance in Urtica dioica L.and a two peak course was displayed.The order of T3 T2 T1 T4T5 was founded in Tr and Gs.The water use efficiency culminated in the early morning.And the water use efficiency in forenoon was higher than that in afternoon.