不同水分条件下梭梭和多花柽柳苗期光合特性及抗旱性比较

在新疆墨玉县对不同水分条件下大田栽植的梭梭和多花柽柳苗期的净光合速率（Pn）、蒸腾速率（Tr）、水分利用效率(WUE)、气孔导度（Gs）和胞间CO2浓度（Ci）等光合生理指标进行了测定,同时测定了不同灌水量下梭梭和多花柽柳在不同时刻的叶片水势,以及两树种叶片的稳定碳同位素比率。结果表明:①梭梭和多花柽柳的水势在一天中的变化趋势呈“V”字型,不同处理下多花柽柳的水势日平均值略大于梭梭。②不同灌水量对梭梭和多花柽柳的水分利用效率影响不显著,在相同处理下,梭梭的水分利用效率总是大于多花柽柳。③梭梭的δ13C值为-12.65‰～-13.39‰,多花柽柳的δ13C值为-26.85‰～-27.70‰。梭梭的δ13C值显著大于多花柽柳（P<0.05）,表明梭梭的长期水分利用效率较高。④运用隶属函数综合各个指标的比较结果来看,梭梭的抗旱性强于多花柽柳。

Comparison of Drought Resistance and Photosynthetic Characteristics of Haloxylon ammodendron and Tamarix hohenackeri at Seedling Stage under Different Moisture Conditions

The physiological indices,such as net photosynthetic rate(Pn),transpiration rate(Tr),water use efficiency(WUE),stomatal conductance(Gs),intercellular CO2 concentration(Ci),etc,of Haloxylon ammodendron and Tamarix hohenackeri at seedling stage were studied under field environmental conditions in Moyu county of Xinjiang.Simultaneously their leaf water potential and leaf δ13C ratio were determined.Results showed:(1)The diurnal variation of leaf water potential of Haloxylon ammodendron and Tamarix hohenackeri showed "V" shape;the daily mean water potential of Tamarix hohenackeri was slightly higher than Haloxylon ammodendron under different irrigation quota;(2) The effects of different irrigation quota on water use efficiency were not significant,but the water use efficiency of Haloxylon ammodendron was higher than Tamarix hohenackeri in the same water treatment;(3) The δ13C value of Haloxylon ammodendron varied in range of-12.65‰～-13.39‰,Tamarix hohenackeri varied in-26.85‰～-27.70‰;water use efficiency of Haloxylon ammodendron was significantly higher than Tamarix hohenackeri(P<0.05),this showed the water use efficiency of Haloxylon ammodendron was relatively higher in a long time;(4) Integrated analysis of all the indices by membership function showed drought resistance of Haloxylon ammodendron was higher than Tamarix hohenackeri.