滇中高原磨盘山常绿阔叶林营养元素分配格局1）

对滇中高原磨盘山常绿阔叶林群落的N、P、K、Ca和Mg这5种营养元素的质量分数、积累及分配格局进行研究，结果表明：乔木层植物叶片营养元素 N、P、K、Ca、Mg质量分数分别为14．805～21．337、0．574～1．361、2．097～13．851、2．846～12．780、0．680～2．839 g· kg－1；不同植物种对营养元素具有选择吸收性，除树枝外，各器官营养元素质量分数均以N最高，其次是K和Ca，Mg和P最低；除Ca外，各营养元素质量分数在树叶中最高，树干中最低；Ca和Mg质量分数显著低于中国亚热带森林平均水平，是影响磨盘山森林生产力的重要因素；群落营养元素总积累量为5125．185 kg· hm－2，乔木层、灌木层、草本层和凋落物层营养元素积累量所占比例依次为78．581％、4．461％、0．007％和16．951％，凋落物营养元素积累量明显高于林下植被层，林木归还给土壤的养分较为丰富，能够维持该生态系统的稳定和平衡；绝大部分树种属于P限制型植物，磨盘山常绿阔叶林植物生长总体上受P的制约。

Distribution Pattern of Nutrient Elements of Evergreen Broad-leaved Forest in Mopanshan,Middle Yunnan Plat-eau

We studied the nutrient (N, P, K, Ca and Mg) distribution pattern and accumulation of evergreen broad-leaved for-est in Mopanshan in Yuxi , middle Yunnan plateau , southwest China .The nutrient contents in leaves of the tree layer were 14.805-21.337 g· kg for N, 0.574-1.361 g· kg for P, 2.097-13.851 g· kg for K, 2.846-12.780 g· kg for Ca, and 0.680-2.839 g· kg-1 for Mg, respectively.Plants had the selective absorption of nutrient elements .N was the nutrient element with highest content of each organ except the branch , followed by K and Ca , and Mg and P had the lowest con-tents.Each nutrient element had the highest content in the leaf and the lowest in the stem except Ca .The correlation be-tween the content of each nutrient element in leaves was poor .There was just a significant correlation between K and Mg . The contents of Ca and Mg were significantly lower than the mean level of subtropical forest in China , which were important factors that affected the forest productivity of Mopanshan .The whole community accumulation of nutrients was 5 125.185 kg· hm-2 .The tree layer accounted for 78.581%, the shrub layer accounted for 4.461%, the herb layer accounted for 0.007%and the litter layer accounted for 16.951%.Litter nutrient accumulation was significantly higher than that of the under-growth layer .It could maintain the stability and balance of the ecosystem .The plants were almost restricted by P .The growth of evergreen broad-leaved forest plants of Mopanshan were restricted by P on the whole .P is the limiting factor for this community productivity .