英罗港红树植物群落不同演替阶段植物元素分布及其与土壤肥力的关系

ELEMENT DISTRIBUTION AND ITS RELATIONSHIP WITH SOIL FERTILITY IN DIFFERENT SUCCESSION STAGES OF A MANGROVE COMMUNITY IN YINGLUO BAY, GUANGXI

根据广西英罗港红树植物群落的演替过程 ,研究了 5个主要演替阶段红树植物群落优势种地上部分的 7种元素 (N、P、K、Ca、Mg、Na、Cl)含量、群落元素积累量及其与土壤肥力的关系。结果表明 :1)红树植物不同器官元素含量大小为 :N、P、K均为花果 >叶 >枝 >皮 >干 ,Ca为皮 >枝、叶 >花果 >干 ,Mg为花果 >叶 >皮 >枝 >干 ,Na、Cl为叶、花果 >皮 >枝 >干 ;2 )同一器官中各元素含量均以Cl、Na最多 ,其次是N、Ca、K ,然后是Mg ,最少是P ;3)随着进展演替 ,红树植物群落优势种的N、P、K含量呈明显减少趋势 ,Ca、Na和Cl含量 (除木榄 (Bruguieragym norrhiza)外 )则呈现相反的趋势 ,而Mg含量缺乏明显的规律性 ;4) 7种元素在群落里的积累量大小顺序为红海榄(Rhizophorastylosa)群落 (4 2 82 .4kg·hm-2 ) >木榄群落 (2 96 4.2kg·hm-2 ) >秋茄 (Kandeliacandel)群落 (2 831.9kg·hm-2 ) >桐花树 (Aegicerascorniculaturn)群落 (134 2 .0kg·hm-2 ) >白骨壤 (Avicenniamarina)群落 (747.1kg·hm-2 ) ,其趋势是随着进展演替而增大 ;5 )不同演替阶段红树植物群落优势种的N、P、K、Ca 4种营养元素含量和群落元素总积累量与土壤肥力因素密切相关。可见 ,红树植物群落元素分布特征反映了红树植物对潮滩特殊生境的适应 ,而?

The Yingluo Bay is located in Hepu county, Guangxi, China, and has an area of mangrove approximately 80 hm 2 in size. These mangrove communities belong to the estuarine mangrove vegetation type. These communities show distributional zones in the different inter tide levels. The vegetation type of mangrove communities distributing from the mean low tide, the mean intermediate tide to the mean high tide are the communities accordingly with the dominant species (including Avicennia marina, Aegiceras corniculatum, Kandelia candel, Rhizophora stylosa, Bruguiera gymnorrhiza). Additionally, there are some transitional vegetation types in these dominant communities. All the communities above reflect the succession process of the mangrove. Based on the succession process of mangrove communities in the Yingluo Bay, the authors divided these communities into five main succession stages according to the two dominant aspects of the community: composition and mean inter-tidal level. These communities include (named after the dominant species present): A. marina community, A. corniculatum community, K. candel community, R. stylosa community, and B. gymnorrhiza community. The authors measured the biomass on the floor by on-the-spot survey and weighted means measure, and also measured the amount of accumulated elements in different mangrove communities. The content of seven elements (N, P, K, Ca, Mg, Na, Cl) in the five dominant species was also measured. Furthermore, the authors researched the relationships between element distribution in the mangrove communities and soil fertility. The results showed the following: 1) The element content of different organs in the five mangrove dominant species was: for N, P, K flower and fruit>leaf>branch>bark >stem, Ca:bark >branch>leaf>flower and fruit>stem; for Mg: flower and fruit>leaf>bark>branch>stem; for Na, Cl:leaf or flower and fruit>bark>branch>stem. As for the coefficient of variation (CV) of the different element's content, the highest was K, lower were N, P, Na, Cl, and the lowest were Ca, Mg. As for the CV in the mean content of the same element in different organs, the highest was bark, then stem, and the lowest were leaf, flower and fruit. 2) As for the different elements contents in the same organs, the highest was Na and Cl, then N, Ca, K, then Mg, and the lowest was P. N was most significantly correlated with many other elements, P and K with fewer, and then Na and Cl the least. Ca and Mg were not correlated with other elements. Na and Cl elements were correlated at the 0.05 level in the stem, and at the 0.01 level in leaf, branch and bark. As for the numerous related elements pairs in different organs, leaf, branch and bark have the most correlated element pairs, and then branch. 3) The mean content order of N, P, and K in different mangrove species was A. marina>A. corniculatum> K. candel>R. stylosa>B. gymnorrhiza, reflecting the gradual reduction of these elements with the succession process of mangrove communities and showing the stratification in these communities. The content of N, P, and K in the lower stratum was higher than that of the upper stratum, while the Ca, Na, and Cl content showed the reverse tendency (except for B. gymnorrhiza). The Mg content showed no evident pattern. 4) There were evident differences in the amounts of the seven elements accumulated in the different successional stages of the mangrove communities. The order was as follows: R. stylosa community (4282.4 kg·hm -2) > B. gymnorrhiza community (2 964.2 kg·hm -2)> K. candel community (2 831.9 kg·hm -2)> A. corniculatum community (1 342.0 kg·hm -2) > A. marina community (747.1 kg·hm -2). The increment tendency increased with the succession process. 5) As for the mean elements contents of the five dominant species in the mangrove communities and the corresponding soil fertility aspects (pH value, organic matter, total N, total P, available N, available P, invertase, urease and acid phosphatase), there was close correlation between the soil fertility aspects and the Mg, Na, an