土壤水分胁迫对短葶山麦冬光响应特性的影响

摘要

Four different levels of water stress, mild water stress ( Wl) , moderate water stress ( W2) , severe water stress ( W3 ) and the control ( CK) were applied to study the effects of water stress on the photosynthetic response of Liriope muscari under pot cultural condition by controlling soil water content. The results showed that net photosynthetic rate ( Pn) was CK > W2 > Wl > W3 when PAR was above 200 μmol·m-2'·s-1. Water stress lowered the max net photosynthetic rate and apparent quantum efficiency and the decreasing amplitude of W3 was the biggest. W3 increased the light compensation point and light saturation point. The water use efficiency reached maximum at the 400 μmol·m~-2·s-1l of PAR under the different soil water moisture. 50% and 35% of field water-holding capacity increased the water use efficiency of L muscari.%以盆栽的短葶山麦冬为材料,研究不同土壤水分梯度即土壤含水量分别为土壤田间持水量的80％(CK)、65％(W1)、50％(W2)和35％(W3)条件下,短葶山麦冬光合作用—光响应特性.结果表明,当光合有效辐射高于200 μmol·m-2· s-1时净光合速率表现为CK ＞W2 ＞W1 ＞W3,水分胁迫处理降低了最大净光合速率和表观量子效率,重度水分胁迫(W3)降幅最大,W3提高了光补偿点和光饱和点.不同土壤水分条件下短葶山麦冬水分利用效率均在光合有效辐射为400 μmol·m-2·s-1时达到最大值,50％和35％的土壤田间持水量条件下提高了短葶山麦冬的水分利用效率.