芒萁群落中营养元素的循环特点

CHARACTERISTICS OF NUTRIENT ELEMENTS CYCLING IN FERN COMMUNITY

本文研究了广泛分布于亚热带地区的芒萁群落营养元素循环特点,并提出了氮、磷、钾、钙、镁、铝、锰7种元素动态循环模型。结果表明:(1)N、P、K、Al 4种元素以活根茎中积累最大,一方面体现了芒萁以根茎繁殖的特点,另一方面也体现了芒萁富集元素的特点。Ca、Mg、Mn 3种元素以羽叶中积累最大,体现了3种元素与叶及叶绿素构成有关的生理特点。(2)N、P、K 3种元素含量随时间推移而下降,表现出“稀释效应”。Al正相反,表现出“浓缩效应”。Ca、Mg含量在生长初期的5月及生长高峰期的9月最高,Mn含量在5—9月较稳定,以后3种元素含量逐步下降,7种元素含量序列为N>K>Al>Ca>Mg>P>Mn。(3)芒萁明显富集Al,而富集Mn不明显。(4)芒萁群落各元素循环特点表明芒萁对环境资源的利用能力有限,应适当加以改造。(5)建立了芒萁-土壤系统中7种元素循环模型。

The characteristics of nutrient elements cycling in D.dichotoma community have been studied. -The cycle process of nutrient elements in this community was analysed and some dynamic models of elements N,P,K,Ca, Mg,Al and Mn were established. The results are as follow: (1) The storages Of N,P,K, and Al were the highest in live rhizomes. This shows that the rhizomes are reproduction organ and concentration organ. The storages of Ca,Mg, and Mn were the highest in pinnules because these elements are structure matters of chlorophyll. (2 ) The concentration of N, P and K decreased with time because of 'dilution effecf.Al concentration increased with time because of 'concentration effect'. The concentrations of Ca,Mg and Mn decreased after Septemper. The concentrations of seven elements were in the following order: N>K>Al>Ca>Mg>P>Mn. (3) The community enriched Al but did not enrich Mn. (4) The total amount of the seven elements were located largely in soil and very little in community. This shows that the community has little ability to conserve and utilize the elements. (5) Cycling dynamic models of the seven elements have been established.