红皮云杉幼树不同光环境下生理生态特征研究

为了探讨红皮云杉光舍特征与树木枝叶分布格局，生物量及其分配的关系，采用人工控制光照环境，在4个光照条件下进行红皮云杉生长试验，结果表明，红皮云杉幼树瞬时最大净光合速率以透光70％处理最大，10％处理最小，对数据进行方差分析，结果差异显著；并且净光合速率最大的处理其暗呼吸速率也最大，光补偿点和光饱和点也随透光率而变化，透光率小(10％)的处理光补偿点也小，说明云杉幼树对庇荫环境的适应；不同光照条件下幼树的形态特征也表现出明显差异，长期生活在相对较暗的光环境中，形成细而高的树干，侧枝数量增加、长度加长，侧枝角度增大；云杉小苗(9年生以前)以相对照度70％处理生物量最大，9年生以后以全光区生物量最大，说明云杉在9年生以前耐庇荫，9年生以后喜光。

Preliminary study on major eco- physiological characteristics of spruce seedlings under different light environment

Artificial light-control was used within four light gradient environments to simulate the growth of spruce seedlings so as to study the relationship between photosynthetic characteristics of spruce seedlings and branch-and-leaf distribution and biomass as well as its distribution. The results showed that the instant net photosynthetic rate (NPR) of seedlings growing under 70% relative illumination (RI) is biggest and those growing under 10% RI is least. The statistics showed a significant difference. Moreover, the respiration rate of seedlings with the biggest NPR is the biggest correspondingly. The light compensation point (LCP) and light saturation point (LSP) change with relative illumination. The LCP of Those growing under low light radiation is smaller, which explains the seedlings' tolerance to the shade. The seedlings' morphological characteristics have significant difference due to different light environment. Growing under lower light environment permanently, the seedling has a thin and tall stem, much more long branches with a bigger angle. The younger seedlings (no more than 9yr ) with the most biomass are those growing under 70% RI zone. After 9 years, the biomass of seedlings growing under full light are the biggest, which explain the seedlings tolerate to the shade before 9 years and need light later.