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梭梭(Haloxylon ammodendron)与白梭梭(H.persicum)是古尔班通古特沙漠植物群落2个最主要的建群种。通过对梭梭与白梭梭光合特性及相关环境因子的同期观测,探讨其光合响应特征及其与环境因子关系的异同。结果表明:梭梭对弱光的利用能力大于白梭梭,而白梭梭利用强光的能力大于梭梭。梭梭和白梭梭净光合速率(P n)、气孔导度(G s)、蒸腾速率(T r)的日变化特征均为“单峰”型,但P n、G s峰值出现时间略有差异,T r的峰值出现时间为16:00。根据梭梭和白梭梭P n、胞间CO2浓度(C i)及气孔限制值(L s)的变化方向,推测梭梭光合“午休”主要由气孔因素引起。白梭梭日平均P n、T r和WUE(水分利用效率)均高于梭梭,说明白梭梭是一种高光合、高蒸腾、高水分利用效率的物种。相关分析表明,对梭梭、白梭梭的P n影响最显著的环境因子是光量子通量密度(PPFD)。
Haloxylon ammodendron and H. persicum are the two most important constructive species of the Gurbantunggut desert plant community. By observing the photosynthetic characteristics of Haloxylon ammodendron and Haloxylon ammodendron and the related environmental factors, the characteristics of photosynthetic responses and their similarities and differences with the environmental factors were discussed. The results showed that the ability of Haloxylon ammodendron to utilize weak light was greater than that of Haloxylon ammodendron, while the ability of Haloxylon ammodendron to use strong light was greater than that of Haloxylon ammodendron. The diurnal variations of net photosynthetic rate (P n), stomatal conductance (G s) and transpiration rate (T r) of Haloxylon ammodendron and Haloxylon ammodendron were both “unimodal”, but the peaks of P n and G s appeared The time is slightly different, and the peak appearance time of T r is 16:00. According to the change direction of P n, C n and stomatal limitation (L s) between Haloxylon ammodendron and Haloxylon ammodendron, it was speculated that Haloxylon ammodendron was mainly caused by stomatal factors. The daily average P n, T r and WUE (water use efficiency) of white Haloxylon ammodendron were higher than that of Haloxylon ammodendron, indicating that Haloxylon ammodendron was a species with high photosynthesis, high transpiration and high water use efficiency. Correlation analysis showed that the most significant environmental factor affecting the P n of Haloxylon ammodendron and Haloxylon ammodendron was photon flux density (PPFD).