盐胁迫对柽柳和白刺光合日变化的影响

为了筛选耐盐植物以便在盐碱地推广种植，以2 年生的白刺和柽柳为试验材料，设定NaCl 溶液浓度梯度为0(CK)、100(Y1)、200(Y2)、400(Y3)、600(Y4) mmol/L，研究盐胁迫下对白刺和柽柳的光合日变化的影响。结果表明：（1）柽柳与白刺在盐胁迫下的日平均光合速率(Pn)变化趋势与非盐胁迫情况下基本相同；（2）白剌的光合能力强于柽柳；（3）随着盐浓度的增加，白刺的日平均光合速率(Pn)和羧化效率(CE)的降低速率比柽柳快；柽柳在盐胁迫下的水分利用效率(WUE)比非盐胁迫下高，但白刺仅在Y1和Y2 处理下较对照高，并且柽柳的水分利用率始终大于白刺；（4）柽柳从Y3 处理开始出现盐胁迫造成的非气孔限制，白刺从Y1 处理就开始出现盐胁迫造成的非气孔限制。综上所述，说明柽柳的耐盐能力强于白刺，更适合在研究区条件下推广种植。

Effect of Salt Stress on Diurnal Variation of Photosynthesis of Nitraria tangutorum and Tamarix chinensis

In order to select salt-tolerant plants for planting in saline soil, 2-year-old Nitraria tangutorum and Tamarix chinensis are used as experimental material. At the same time, NaCl concentration gradient is setted 0 (CK), 100 (Y1), 200 (Y2), 400 (Y3), 600 (Y4) mmol﹒L-1 in order to study photosynthetic diurnal variation of them under salt stress. The results showed that: (1) The trend of the average photosynthetic rate (Pn) of them under salt stress was basically the same with non-salt stress conditions; (2) The photosynthetic ability of Nitraria tangutorum was stronger than tamarisk; (3) With salt concentration increasing, the decline rate of Nitraria tangutorum was greater than Tamarix chinensis in average daily net photosynthetic rate (Pn) and carboxylation efficiency (CE);The water use efficiency (WUE) of Tamarix chinensis under salt stress was higher than non-salt stress, but the WUE of Nitraria tangutorum was higher than the comparison only in Y1 and Y2 processing, and the WUE of Tamarix chinensis was always greater than Nitraria tangutorum. (4) Tamarix chinensis began to appear non-stomatal limitation caused by salt-stress from Y3 treatment, white Nitraria tangutorum appeared from Y1 treatment. In summary, the salt tolerance of Tamarix chinensis is stronger than Nitraria tangutorum and Tamarix chinensis is more suitable for planting under the conditions of the study area.