固沙树种梭梭在不同水分梯度下的光合生理特征

对不同水分梯度下梭梭光合作用的研究发现，地下水位、土壤含水量、灌水量对梭梭的光合具有明显的影响。在1．4m、2．4m、3．4m地下水位下，梭梭的光合速率、呼吸作用、量子效率随水位的降低而降低，光补偿点随水位的降低而增大；在滴灌供水时，梭梭的光合速率较对照明显提高，且灌水量越大，梭梭的光合速率越高；半流动沙丘、丘间低地、粘土沙障固定沙丘退化梭梭的光合作用的强弱同其林地土壤水分的高低基本一致。7月，不同水分梯度下的梭梭光合作用均表现出午休现象，9月只有立地条件较差的梭梭发生光合午休，而且9月光合作用要强于7月，说明9月环境条件更有利于梭梭生长。

Photosynthesis-physiological characteristics of Haloxylon ammodendron under different soil moisture grades

The photosynthetic rate of Haloxylon ammodendron Bge. under the different soil moisture grades was researched. The results showed the water table, the soil moisture and the irrigated water quantum affect the photosynthetic rate of Haloxylon ammodendron obviously. At the water table of 1.4 m,2.4 m and 3.4 m, the photosynthetic rate,the respiration rate and the apparent quantum efficiency(AQE) decreased with reduce of the water table, but light compensation point(LCP)increased. Compare with CK, the photosynthetic rate of Haloxylon ammodendron by drop irrigation increased obviously. More water quantum, higher the photosynthetic rate of Haloxylon ammodendron Bge.. The photosynthetic rate of Haloxylon ammodendron planted on semisand dunes, land between sand dunes and fixed sand dunes with clay sand barrier was enlarged with increase of the soil moisture basically. In July, the photosynthetic rate of Haloxylon ammodendron under the different soil moisture occurs midday rest, but in September only those that environment conditions are worse occur midday rest. Compared to July, the photosynthetic rate of Haloxylon ammodendron in September is stronger, and its environment conditions is more benefit to matter synthesize of Haloxylon ammodendron grown in the arid area.