辽东山区主要阔叶树种叶片养分含量和再吸收对落叶时间的影响  

Effects of leaf nutrient concentration and resorption on leaf falling time of dominant broadleaved species in a montane region of eastern Liaoning Province, China

作　　者：申奥 朱教君[1,2] 闫涛[1,2,3] 卢德亮[1,2,3] 杨凯 SHEN AO;ZHU Jiao-Jun;YAN Tao;LU De-Liang;YANG Kai(Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China;Qingyuan Forest Chinese Ecosystem Research Network, Chinese Academy of Sciences, Shenyang 110016, China;University of Chinese Academy of Sciences. Beijing 100049, China)

机构地区：[1]中国科学院沈阳应用生态研究所中国科学院森林生态与管理重点实验室,沈阳110016 [2]中国科学院清原森林生态系统观测研究站,沈阳110016 [3]中国科学院大学,北京100049

出　　处：《植物生态学报》2018年第5期573-584,共12页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31330016和31570600)~~

摘　　要：凋落物是森林生态系统养分的重要来源,叶片脱落时间是影响其分解的关键因素。东北温带森林中蒙古栎(Quercus mongolica)落叶时间较其他树种晚,在山脊等贫瘠立地叶片甚至第二年春天才脱落。我们假设:相对于其他树种,蒙古栎叶片养分元素含量过高、再吸收时间长,导致叶片延迟脱落。为验证假设,除蒙古栎外,选择了落叶时间居中的色木槭(Acer mono)和落叶较早的胡桃楸(Juglans mandshurica)为对象,持续监测叶片从成熟至凋落过程中叶片养分元素含量,包括大量元素:氮(N)、磷(P)、钾(K)、钙(Ca)和镁(Mg),微量元素:铁(Fe)、铜(Cu)、锰(Mn)和锌(Zn);并分析养分再吸收率。结果表明:蒙古栎成熟叶养分元素含量介于对照树种之间;凋落叶N、P和K含量低于对照树种,Fe和Mn含量高于对照树种,其余元素含量介于对照树种之间。该结果不支持"蒙古栎叶片养分含量过高"假设。蒙古栎叶片N、P和K再吸收率高于对照树种,再吸收率高低与其落叶时间完全一致;叶片Cu和Zn再吸收率与对照树种无显著差异;叶片其余元素未发生再吸收,其累积率与对照树种无显著差异;说明养分再吸收与养分含量无关,可能与树种的种专一性相关,可能会影响叶片脱落时间。由于蒙古栎多生长在贫瘠土壤,其成熟叶无法积累更多养分;为避免叶片脱落后养分进入土壤被其他物种利用,将养分尽量回收储存于自身,即蒙古栎叶片养分再吸收过程较长,叶片脱落较晚。生长在极端贫瘠立地的蒙古栎叶片次年春天才落叶,可能是由于再吸收一直在进行,来不及脱落而保留至新生长季开始。落叶晚的树种养分再吸收率高、有利于自身养分保存,更能适应贫瘠土壤,反之亦然。Aims Litter is an important source of nutrient in forest ecosystems, and its decomposition rate has a significant impact on soil nutrient supply. Previous observations indicated that different leaf falling time resulted in different litter decomposition rates. We found that the leaf falling time of Quercus mongolica was later than that of other tree species, especially in the barren soil. However, it is not yet clear why the leaves of Q. mongolica fall later. We hypothesized that the leaves of Q. mongolica had higher nutrient concentration, and longer time for resorption, which could lead to the later time of leaf falling. Methods We continuously measured N, P, K, Ca, Mg, Cu, Fe, Mn and Zn concentrations in leaves of three tree species （Q. mongolica, the leaf falling time is the last; Juglans mandshurica, the leaf falling time is the earliest, Acer mono, the leaf falling time is in between Q. mongolica and d. mandshurica） from leaf maturity （August） to litter fall （October） in a montane region of eastern Liaoning Province. We analyzed leaf nutrient concentrations and resorption efficiencies of each species.Important findings The nutrient concentrations in mature leaves of Q. mongolica are similar to those of other tree species. N, P and K concentrations in the litter of Q. mongolica were significantly lower than those of other species （p 〈 0.05）, and the resorption efficiencies were generally consistent with the leaf falling time. These findings did not support the hypothesis that leaves of Q. mongolica have higher nutrient concentrations than other species. The resorption efficiencies of N, P and K did not influence leaf nutrient concentrations, but were directly related to the biological characteristics of tree species. The leaves of Q. mongolica fall later, which might be due to the high adaptability of Q. mongolica to the barren soil. Although the mature leaves could not accumulate more nutrients from barren soil, they increased the nutrient use efficiency by prolonging the nutrient resorpti

关 键 词：叶片养分含量 养分再吸收率 叶片凋落时间 阔叶树种 

分 类 号：S718.5[农业科学—林学]