地下水埋深及矿化度对多枝柽柳幼苗光合特征及生长的影响

采用简易Lysimeter研究了不同地下水埋深(20,60,100 cm)和不同矿化度(<1.00 g/L淡水,1.0～3.0 g/L微咸水,3.0～10.0 g/L咸水)对多枝柽柳幼苗光合特征及生长的影响。结果表明,不同地下水埋深与矿化度对多枝柽柳幼苗的光合特征及生长均有影响;在地下水埋深20 cm,矿化度为3.0～10.0 g/L的咸水条件下,多枝柽柳幼苗的最大光合速率(Pnmax)为66.93μmol/(m2.s),光合速率(Pn)、气孔导度(Cond)、水分利用效率(WUE)及羧化速率(CE)对光强的响应均大于其它试验处理。不同的地下水埋深、矿化度可显著影响多枝柽柳幼苗的最大光合速率(Pnmax)、表观量子效率(AQY)、暗呼吸速率(Rd)、光饱和点(LSP)等光合特征。进一步分析表明,在地下水埋深20 cm,矿化度为3.0～10.0 g/L的咸水条件下,多枝柽柳幼苗的生态适应能力较强,幼苗能够适应生境变化迅速生长,获得竞争优势。

Effects of Groundwater Depth and Mineralization Degree on Photosynthesis and Growth of Tamarix Ramosissima Seedlings

The effects of groundwater depth and mineralization on the photosynthetic characteristics and growth of T.ramosissima were studied in the treatments with factors of mineralization(<1.00,1.0～3.0,and 3.0～10.0 g/L) and groundwater depth(20,60,and 100 cm) for a duration of 60 days in the national research station of Akesu oasis farmland ecosystem.The results indicate that the combination of groundwater depth and mineralization showed significant effects on the photosynthetic characteristics and growth of T.ramosissima seedlings.According to the results obtained from the experiment,it was found that with groundwater at 20 cm depth and saline condition,the plant showed the highest maximum photosynthetic rate(66.93 μmol/(m2·s)),stomatal conductance,water use efficiency and carboxylation efficiency.The values of maximum net photosynthetic rate,apparent quantum yields,light saturation point and dark respiration rate were affected by the variations of groundwater depth and mineralization.These results revealed that with 20 cm watertable and saline condition,the seedlings of T.ramosissima show stronger competency and have higher capacity to accommodate the variations of the environment.