千岛湖次生林优势种幼苗光合特性及其对群落演替的指示意义

利用LCA-4型便携式全自动光合测定仪,于2009年8月下旬晴朗天气,对千岛湖次生林优势种马尾松（Pinus massoniana）、苦槠（Castanopsis sclerophylla）、石栎（Lithocarpus glabra）、青冈（Cyclobalanopsis glauca）幼苗在林窗、林下2种生境中的光合生理生态特性进行了研究.结果表明：（1）在林窗中马尾松光合日进程为＂单峰＂曲线,其他3种均为＂双峰＂曲线,有明显光合＂午休＂现象.在林下这4种幼苗的光合日进程均为＂单峰＂曲线,但曲线平缓,峰值不明显.在林窗中青冈的日均Pn显著低于其他3物种,而在林下马尾松的日均Pn显著低于其余3物种.4个优势种的日均Pn在2种生境中均差异显著.（2）LCP、LSP、Amax、Rd均是马尾松最高,苦槠次之,青冈、石栎较低;青冈、石栎的AQY显著高于马尾松和苦槠,苦槠的AQY也显著高于马尾松.（3）在林窗中,青冈Fm最高,与其他3种均差异显著;Fv/Fm为马尾松最高,显著高于其他3物种.这说明马尾松属强阳性树种,苦槠为阳性树种,青冈和石栎具有较强的耐荫性,随着进展演替,群落郁闭度的增大,马尾松、苦槠将逐渐退出群落,而青冈和石栎将成为群落演替顶极阶段的优势种.

Photosynthesis traits of the dominant plant species seedlings in the secondary forest in Qiandao Lake and its significance in the succession of forest community

The photosynthesis traits of the seedlings of the dominant plant species Pinus massoniana,Castanopsis sclerophylla,Lithocarpus glabra and Cyclobalanopsis glauca in the forest gap and understory habitats were studied by using a LCA4 Portable Photosynthesis System in sunny in August,2009.In the forest gap habitat,the diurnal variation of Pinus massoniana seedling appears as a single peak curve and those of the other plant species seedlings as a typical two-peak curve with obvious midday depression.In the unde...