不同光照强度下楠木属3个树种苗木的形态响应与适应

摘要

The growth, biomass accumulation and allocation of the seedlings of Phoebe bournei, Phoebe chekiangensis,and Phoebe sheareri belonging to Phoebe Nees in response to different light regimes ( 100%of full sunlight,L100;50%of full sunlight,L50;20%of full sunlight L20) were studied.The results of two years’ experiment showed that:(1) All the three species seedlings’height and diameter were the largest under L 50. The leaf width ,average area ,specific leaf area showed an increasing trend with the decrease light intensity ,and there were significant or very significant differences among these indexes .( 2) The total biomass showed a con-sistent trend under different light treatments;under moderate shade conditions ( L50 ), the total biomass in-creased with the increase of light intensity ,but decreased when the light intensity was beyond a threshold .(3) The stem mass ratio and leaf mass ratio decreased with the increase of light intensity ,the mass ratio of the root increased with light intensity .The seedling quality index had the highest value under 50%of light treatment and the differences were significant or extremely significant .%设置100％光照（L100）、50％光照（L50）、20％光照（L20）3种处理，研究不同光照处理对楠木属闽楠、浙江楠和紫楠3个树种苗木生长量和生物量积累和分配的影响。通过2年的试验，结果表明：（1）3个树种的苗高和地径在适度遮荫（ L50）条件下生长较好。叶宽、单叶平均面积、比叶面积均表现为随着光照强度的增加而减少的规律，各指标间则存在显著或极显著差异。（2）在不同光照处理下，总生物量趋势较为一致，在适度的遮荫条件下（L50），总生物量随着光强升高而增加，但光强再高总生物量反而下降。（3）茎质量比和叶质量比随着光照强度的增加而逐渐减少，根质量比则随着光照强度增加而增加。苗木质量指数在50％光照处理下最高，表现出显著或极显著差异。