毛竹的无性系生长与立竹密度和叶龄结构的关系

毛竹为单轴型散生竹，属典型的无性系植物，原产我国亚热带地区。由于其个体高大、生长迅速、产量高、材质好、分布广，长期以来，一直是我国最为重要的经济竹种。本文应用无性系生长生理整合的理论，从种群统计学的角度，探讨了毛竹林立竹密度与叶龄结构对其无性系生长潜力的影响。结果表明：由于毛竹叶的生活期为两年，１龄新叶的光合能力比２龄老叶高，每样地的出笋数、活笋数与带１龄新叶的立竹数呈正相关，而与带２龄老叶的立竹数相关性不显著。另外，竹笋的死亡率是非密度制约的。本研究结果合理地解释了常见的毛竹林产量大小年交替变化的现象。

THE RELATIONSHIP BETWEEN THE CLONAL GROWTH AND THE DENSITY OF ADULT SHOOTS WITH DIFFERENT LEAF AGE IN PHYLLOSTACHYS PUBESCENS MAZEL

Phyllostachys pubescens ,a typical clonal plant,is a monopodial bamboo species native to subtropical China.Its shoots are widely separated each other.Because of its giant size,fast growth,high production,good quality for timber use and wide distribution,it has long been the most important economic bamboo in China.Based on the theory of physiological integration in clonal plants,this paper deals with the influence of the density of adult shoots and leaf age structure on the potential of clonal growth in Phyllostachys pubescens from the point of view of demography.It was shown that because the leaf life span is two years in this bamboo,new (1 year old) leaves had higher photosynthetic capacity than old (2 year old) leaves.The number of new shoots emerging and surviving per plot was positively correlated with the number of adult shoots with new (1 year old) leaves,rather than with that of those with the old.In addition,the mortality of new shoots was density independent.This result may explain the common pattern of alternating fluctuation in the production of new shoots between successive years.