不同年龄华北落叶松叶水势及其影响因素的研究

The leaf water potential and its affecting factors of different ages of Larix principis-rupprechtii

2009年5-10月中旬,在河北省塞罕坝机械林场红水营林区,采用ZLZ-5型压力室水势测定仪(兰州大学)测定了3个不同年龄华北落叶松(Larix principis-rupprechtii)的叶水势。同时用HOBO自动气象站和烘干法测定了气象因子和土壤含水量。研究结果表明:不同年龄华北落叶松叶水势有明显日变化,生长初期(5、6月)和生长末期(9、10月)叶水势最低值出现在12:00点左右,生长盛期(7、8月)叶水势最低值出现在8:00左右;叶水势最高值均出现在早上6:00点左右。在7月份,3个不同年龄华北落叶松所遭受的水分胁迫最强,其中31年生落叶松的水分亏缺更明显。随着月份和树木年龄的变化,叶水势的主要影响因子也不同。气象因子中,温度和光强是主要影响因子,呈负相关关系;土壤含水量和黎明叶水势变化趋势有较好的一致性,黎明叶水势与土壤含水量的最高值均出现在7月份(除31年生)。

At the Hongshui forest range of Saihanba Mechanized Forest Farm,the leaf water potential of three different ages of Larix principis-rupprechtii were observed by ZLZ-5 pressure chamber from May-2009 to Oct-2009.Meanwhile,weather factors and soil water content were measured by HOBO automatic weather station and oven drying method.The results showed that the leaf water potential has an obvious daily changes.In early stage（May and June） and later growth（Sept and Oct）,the minimum value of leaf water potential appeared about 12：00 a.m.,In growing season（June and July）,the minimum value of leaf water potential appeared about 8：00 a.m.;The maximal value of leaf water potential appeared about 6：00 a.m.Three different ages of Larix principis-rupprechtii suffered the strongest water stress in July,the effect of 31 year-old Larix principis-rupprechtii is obvious especially.Along with the changes of months and ages of tree,the major influential factors of leaf water potential is also changed.Among the weather factors,the temperature and light intensity is mainly influential factors,appeared negative correlativity.The tendency of soil water content and leaf water potential changes have a obvious consistency,the maximal values of both leaf water potential and soil water content appeared in July（except 31 year old）.