不同林齡馬尾松各器官C、N、P質量分數及化學計量特征1)

劉平 楊章旗 顏培棟 唐生森 謝雨瑤

(廣西壯族自治區林業科學研究院，南寧，530002)

The experiment was conducted to investigate the distribution patterns of C, N and P elements in various organs of Pinus massoniana plantations in southern of Guangxi and their ratio characteristics in order to reveal the nutrient balance mechanism and spatial and temporal dynamics of Pinus massoniana plantations. P. massoniana plantation forests in Guangxi state-owned Paiyang Mountain Forestry were used to analyze and compare the elemental contents and ecological stoichiometry of C, N and P in leaves, branches, stems, bark and roots of P. massoniana at different forest ages. The C, N and P contents were the highest in the leaves and the lowest in the roots, and the N and P contents in the stem were the lowest and significantly different from those in the leaves, branches, bark and roots (p<0.05). Both w(C)∶w(N) and w(C)∶w(P) showed the highest in the stem, and w(N)∶w(P) showed the highest in the bark; and both w(C)∶w(N) and w(C)∶w(P) showed the lowest in the leaves, and w(N)∶w(P) showed the lowest in the stem. The mean C, N and P contents in the leaves tended to increase and then decrease with increasing forest age, while the C and N contents in the roots tended to decrease and then increase. The mean N and P contents were all in the descending order of leaves, branches, roots, bark and stem, and the mean C, N and P contents of P. massoniana were all maximum at the mature forest stage. The correlation analysis showed that the organs of P. massoniana have a complex coordination mechanism. On the whole, the nutrient element content of all organs of P. massoniana is characterized by high C, low N and low P. Moreover, the w(N)∶ w(P) of P. massoniana leaves is limited by N. In order to ensure the development of P. massoniana plantations, it is recommended to apply more N and P fertilizers during the nurturing management process.

生態化學計量學是研究生態系統功能中多種化學元素(碳(C)、氮(N)、磷(P)為主要元素)和能量平衡關系的科學，是分析多種化學元素的質量平衡對生態交互作用影響的一種重要工具[1]。其理論通常用于植物養分關系的研究，在判斷植物養分限制特征方面具有較強的實用性[2-4]。碳、氮、磷是植物生長和生態系統功能維持所不可或缺的重要元素，碳是植物體干物質的主要組成元素，而氮和磷分別是合成蛋白質和遺傳物質的主要元素[5-6]。植物受不同生理過程中養分需求、各器官養分儲存及功能性分化差異性的影響，導致同一植物不同器官化學計量特征存在差異[7-8]。林齡與植物養分限制具有密切關系，對研究植物不同器官化學計量特征隨林齡變化對植物不同器官養分分配和養分需求狀況具有指示作用[9-10]。

馬尾松(Pinusmassoniana)是我國南方主要用材樹種之一，具有速生、豐產的特點，已成為我國南方造林的先鋒樹種[11]。近年來，諸多學者對馬尾松生態系統化學計量特征開展了不少研究。雷麗群等[12]通過對廣西馬尾松天然林不同林齡(6、16、23、35 a)研究，認為隨著樹木進入成熟階段，土壤中有機碳和全氮開始回升。潘復靜等[13]通過對不同林齡馬尾松人工林凋落葉養分變化研究，發現較高林齡馬尾松對氮和磷重吸收較低，而林齡較低的馬尾松對氮和磷重吸收較強。關于馬尾松生態系統的研究中，目前主要側重于葉片[14]、土壤理化性質和凋落物對生態系統的影響[15-16]，而有關馬尾松不同器官間化學計量特征的研究較少。……