NaCl胁迫下秋眠型紫花苜蓿光合作用特性的研究

以中苜一号为对照,研究NaCl溶液(0,50,100,150和200 mmol.L-1)处理下秋眠型紫花苜蓿Maverick、Vernal、Pioneer5446的光响应动态,观察形态特征和盐害级别,用Li-6400光合仪测定叶片净光合速率(Pn)、气孔导度(Gs)和细胞间隙CO2浓度(Ci)。结果表明,随NaCl浓度的增加和胁迫时间的延长,Maverick、Vernal、Pioneer5446和中苜一号叶片的盐害级别均加大,但品种间和处理间盐害出现的时间早晚和最终盐害程度不同。在50和100 mmol.L-1 NaCl的较低浓度下秋眠型紫花苜蓿和中苜一号光合响应存在着预警阶段恢复阶段-耗尽阶段,在150和200 mmol.L-1 NaCl的高浓度下,紫花苜蓿光响应直接进入耗尽阶段。秋眠型紫花苜蓿的耐盐性低于中苜一号。

Research on photosynthetic characteristics of fall dormant alfalfa under salt stress

Using Zhongmu No.1 as CK,the photosynthetic responses of Maverick,Vernal and Pioneer5446 to salinity stress by different NaCl concentrations(0,50,100,150,200 mmol.L-1) were studied,observing morphological features and levels of salt injury.The net photosynthetic rate(Pn),stomatal conductance(Gs) and intercellular CO2 concentration(Ci) was measured by using Li-6400 under NaCl stress.The results showed that with the increase of NaCl concentration and stress time,the level of salt damage had increased in Maverick,Vernal,Pioneer5446 and Zhongmu No.1,while the level of salt damage was different among varieties and treatments.The photosynthetic response of Maverick,Vernal,Pioneer5446 and Zhongmu No.1 consisted of alarm phase,phase of resistance or restoration and phase of exhaustion under 50 and 100 mmol.L-1 NaCl.Where as under 150 and 200 mmol.L-1 NaCl,the photosynthetic response of Maverick,Vernal,Pioneer5446 and Zhongmu No.1 had nothing but the phase of exhaustion.The salt tolerance of fall dormant alfalfa was lower than that of Zhongmu No.1.