三倍体毛白杨无性系叶片养分含量的季节变化

Studies on seasonal variations of foliar nutrient contents of triploid Populus tomentosa

为了研究三倍体毛白杨幼林阶段不同无性系叶片养分含量的季节变化,在造林后的第2、3和4年中,每年连续在春、夏和秋季对叶片养分含量进行测定分析。通过将测定结果进行重复测量的方差分析表明:叶片养分含量的季节变化之间有显著差异;元素P、Ca、Mg、Fe和Mn的季节含量以及N与P含量的比值(N/P)随林龄不同而有显著差异。在元素含量随季节变化的趋势分析中,P、N/P、K和Mn含量随时间的变化趋势近似为线性,元素N、Ca、Mg、Fe、Cu和Zn的含量变化趋势近似为曲线。通过组间效应方差分析得出叶片养分元素含量均随不同林龄的变化有显著差异,而对于不同无性系,只有元素Mg和Mn的含量在无性系之间存在显著差异。

In order to attain a better understanding of the nutrient dynamics in Populus tomentosa, contents of N, P, K, Ca, Mg, Fe, Mn, Cu and Zn were determined in foliage in every spring, summer and autumn from 2- to 4-year-old poplar plantation. And statistics were analyzed in the way of repeated measures by SPSS 17.0. The results showed that seasonal dynamics of foliar nutrient contents varied significantly. In addition, foliar P, Ca, Mg, Fe, Mn contents and N/P ratios changed remarkably with the age of the plantations. At the same time, the seasonal trends of P, K, Mn contents and N/P ratios obeyed linear models, while those of N, Ca, Mg, Fe, Cu and Zn contents followed quadratic models. Moreover, according to the tests of between-subject effects, all nutrient elements contents varied significantly with the plantations ages. But in terms of the clone factor, the Mg and Mn contents varied significantly.