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以额济纳绿洲天然胡杨为研究对象,选择绿洲内典型天然胡杨林型,针对不同年龄和径级的胡杨,选择固定样木,对其光合速率和叶水势进行了同步测定,对二者的基本规律和相关关系进行了科学分析。结果表明:胡杨的水势由低到高的规律是中径级树>小径级树>大径级树,整个白天内出现一个最低值范围,而光合速率由高到低的规律也同样是中径级树>小径级树>大径级树,但日变化为在中午的前后出现两个高峰期,中午时分存在“午休”现象;不同年龄和径级的胡杨其光合速率与叶水势的相关关系为显著的负相关。
Taking Populus euphratica natural Populus euphratica as the research object, the typical natural Populus euphratica forest type in oasis was selected. According to the different age and diameter Populus euphratica, fixed sample wood was chosen to measure the photosynthetic rate and leaf water potential synchronously. Related to a scientific analysis. The results showed that the law of low to high water potential of Populus euphratica was medium-diameter tree> small-diameter tree> large-diameter tree, with a lowest value throughout the day, while the law of the photosynthesis from high to low was also the middle diameter Tree> small-diameter tree> large-diameter tree, but the diurnal variation appeared at two peak periods around noon and there was a phenomenon of “lunch break” at noon. The photosynthetic rate and leaf water potential of Populus euphratica with different ages and diameters The correlation is a significant negative correlation.