氮添加对树木光合速率影响的meta分析  

Meta-analysis of the effects of nitrogen addition on photosynthesis of forests

作　　者：王芳[1,2] 张军辉[1] 谷越[1,2] 赵婷[1,2] 韩士杰[1] 

机构地区：[1]中国科学院沈阳应用生态研究所,沈阳110016 [2]中国科学院大学,北京100049

出　　处：《生态学杂志》2017年第6期1539-1547,共9页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(41675150;41430639)资助

摘　　要：探究氮添加对森林植物生理生态特征及生长的影响可以为探讨全球变化背景下中国森林动态变化机制及保护和管理提供依据。本文对32篇有关氮添加对植物光合作用的文献进行整合分析发现,氮添加整体上促进了树木的光合作用(10.24%),其中对温带森林树木的促进(11.45%)高于热带森林(10.32%);氮添加对阔叶树种光合速率的提高(12.16%)高于针叶树种(6.24%)。氮添加对树木光合作用的影响存在阈值效应,当氮添加量小于25 kg·hm^(-2)·a^(-1)时,光合速率略微提高(6.28%),但不显著;而随氮添加量继续增加,光合速率提高,在25~50和50~100 kg·hm^(-2)·a^(-1)氮添加条件下分别提高了13.50%和13.09%;当氮添加量超过100 kg·hm^(-2)·a^(-1)时,植物光合速率的提高则不显著。施氮时间少于5年时,氮添加显著提高植物光合速率(13.01%);施氮时间超过5年时,反而抑制植物光合速率(-20.63%);这种抑制作用在施氮时间持续10年以后则不显著。氮添加影响植物的光合速率可能是过多的氮使植物体内养分失衡(叶片N增多,P、K、Ca、Mg离子减少),而且叶绿素含量与光合酶合成和活性也随之发生变化的结果。Studies on the effect of nitrogen addition on the eco-physiological traits and growth of forests are of great importance, providing basic information for assessing the mechanism of forest dynamics. Here, we conducted a meta-analysis upon 32 studies to reveal the response of tree photosynthesis to N addition. We found that tree photosynthetic rate increased as a whole （ 10.24% ）, and the influence of N addition on temperate trees （11.45%） was higher than that on tropical trees （10.32%） ; broad-leaved tree species was more sensitive to N addition than conifers. The responses ratio of tree photosynthetic rate varied with N addition level and experimental duration. When the nitrogen addition level was less than 25 kg ·hm^-2·a^-1, tree photosynthetic rate increased （6.28%） insignificantly. The tree photosynthetic rate increased with the nitrogen addition level, with increments of 13.50% and 13.09% at 25-50 and 50-100 kg ·hm^-2·a^-1, respec tively. However, the tree photosynthetic rate increased insignificantly when the nitrogen level was more than 100 kg ·hm^-2·a^-1. Generally, the photosynthetic rate was improved significantly in the experiment less than 5 years, but inhibited in the experiment longer than 5 years. The inhibi- tion effect became insignificant in the experiment longer than 10 years. Excess nitrogen addition would lead to nutritional imbalance in plants （increased foliar N and decreased foliar P, K, Ca and Mg）, which may contribute to the changes of photosynthetic pigments and enzyme activities.

关 键 词：氮添加 光合速率 叶片养分 光合色素 META分析 

分 类 号：S718.43[农业科学—林学]