鼎湖山南亚热带常绿阔叶林植物营养元素含量分配格局研究

DISTRIBUTION PATTERN OF NUTRIENT ELEMENTS IN PLANTS OF DINGHUSHAN LOWER SUBTROPICAL EVERGREEN BROAD-LEAVED FOREST

在鼎湖山南亚热带常绿阔叶林中，植物叶片营养元素含量为：Ｎ ０．９４６％一２．５３５％，Ｐ ０．０３０％—０．１２７％， Ｋ ０．６１４％—１．８３３％， Ｃａ ０．４４２％—１．９９５％， Ｍｇ ０．０２４％—０．１８８％。叶片各营养 养元素间相关性较差，仅Ｐ与Ｍｇ及Ｍｇ与Ｋ之间存在显著的线性相关。叶片Ｎ元素平均含量在各层 中的序列为：乔木Ⅲ＞乔木Ⅱ＞乔木Ⅰ＞灌木＞藤本＞草本；其它营养元素浓度随层次分配的规律 性不甚明显，但总趋势为乔木层植物略低于其它层植物。不同营养元素平均含量在各器官中的大小排列 顺序为：Ｎ叶＞皮＞枝＞根＞干；Ｐ叶＞枝＞根＞皮＞干；Ｋ叶＞枝＞皮＞根＞干；Ｃａ 皮＞叶＞枝＞根＞干； Ｍｇ叶＞根＞皮＞枝＞干。大部分植物在同一器官中各营养元素平均含 量序列为：叶、枝和根中均为Ｎ＞Ｃａ＞Ｋ＞Ｍｇ＞Ｐ；干Ｋ＞Ｃａ＞Ｎ＞Ｍｇ＞Ｐ；皮Ｃａ＞Ｎ＞Ｋ＞Ｍｇ＞Ｐ。 对元素含量分配格局分析表明，Ｐ和Ｍｇ很可能是限制南亚热带常绿阔叶林植物生产力的最重要营养元 素。

The investigation of plant nutrient contents in Dinghushan lower subtropical evergreen broad-leaved forest was carried out in August 1996. Sampling was made in Dinghushan Biosphere Reserve, Guangdong, from tree, shrub, liana and herb layers with 5-8 representative species each. It was shown that the nutrient contents in leaves of all plants were N 0.946% - 2.535%, P 0.030% - 0. 127%, K 0.614% - 1 .833%, Ca 0.442% - 1 .995% and Mg 0.024% - 0.188%. Average contents of nutrient elements in various organs and at different layers in the forest were varied. Average nutrient content of N was highest in leaves, and in descending order in barks, branches, root and stems, other elements: P in leaves > branches > roots > barks >stems; K in leaves > branches > barks > roots > stems, Ca in barks > leaves > branches > roots >stems, Mg in leaves > stems > roots > barks > branches. The distribution of elements in most plants was as follows f N>Ca >K>Mg>P in leaves, branches and roots, K>Ca >N>Mg >P in stems, and Ca >N>K>Mg >P in barks. The factors, especially P and Mg, possibly limiting the plant productivity in the area studied are discussed.