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利用WP4露点水势仪对额济纳绿洲胡杨(Populus euphratica)叶水势进行测定,研究了胡杨叶水势的日和月变化规律及其影响因子。结果表明:(1)胡杨叶水势日进程呈“V”形,最小值大都出现在13:00,日均值为-2.53±0.30MPa;月变化呈先上升后下降趋势,月均值为-2.43±0.30MPa。(2)树龄越小对应的叶水势越高;叶片着生部位越高,对应的水势越低;卵圆形叶水势整体稍高于披针形叶水势。(3)叶水势与气温、饱和水汽压差和蒸腾速率呈极显著线性负相关,相关系数依次为-0.87、-0.69和-0.88;与相对湿度和光合速率呈极显著二次多项式相关,相关系数分别为0.85和0.92。胡杨叶水势各方面的综合研究对于明晰胡杨的水分亏缺和抗旱机理有一定的理论指导意义。
The leaf water potential of populus euphratica in the Ejina oasis was measured by using WP4 dew point water potential. The daily and monthly variation of leaf water potential and its influencing factors were studied. The results showed that: (1) Populus euphratica has a daily “V” shape with the minimum values occurring at 13:00 and the average daily average value being -2.53 ± 0.30 MPa. The monthly variation firstly increased and then decreased, 2.43 ± 0.30MPa. (2) The lower the tree age is, the higher the leaf water potential is. The higher the leaf spot is, the lower the water potential is. The oval leaf water potential is slightly higher than that of the lanceolate leaf water potential. (3) Leaf water potential and temperature, saturated water vapor pressure difference and transpiration rate showed a significant linear negative correlation, the correlation coefficients were -0.87, -0.69 and -0.88, respectively; and relative humidity and photosynthesis rate were significantly quadratic polynomial correlation, correlation The coefficients are 0.85 and 0.92, respectively. Poplar leaf water potential in all aspects of comprehensive study for the clear Populus euphratica water deficit and drought resistance mechanism has some theoretical significance.