摘要:选取南方重要的造林树种杉木（Cunninghamia lanceolata（Lamb.） Hook）幼苗为研究对象，通过搭建遮荫棚设置5个光照强度（分别为自然光照的100%、60%、40%、15%和5%），研究了幼苗在不同光照强度下的生长形态、生物量积累及分配、叶片的非结构性碳含量（NSC）特征。结果显示：（1）叶长、叶宽和叶面积在40%光照强度下最大，而比叶面积和叶片相对含水量随着光照强度的降低呈递增趋势；（2）随着光照强度的降低，杉木幼苗各器官生物量下降，根生物量比和根冠比降低，茎和叶生物量比增加；（3）杉木幼苗在60%光照强度下叶片非结构性碳含量最高，5%光照强度下含量最低；（4）杉木幼苗比叶面积与叶生物量以及与非结构性碳含量之间存在极显著的负相关关系（P < 0.01），叶生物量与非结构性碳含量之间存在极显著的正相关关系（P < 0.01）。杉木幼苗能够通过形态学上的可塑性来适应不同的光强环境，提高光竞争能力和生存适合度，但在5%光照强度下，由于较难维持碳收支平衡而不利于其生长和存活。



Abstract:We selected Chinese fir seedlings to study the effects of light intensity on seedling growth, morphology, biomass, biomass allocation, and non-structural carbohydrate (NSC) content in the leaves using a shade house experiment (100%, 60%, 40%, 15%, and 5% of full sunlight). The results showed that:(1) The greatest leaf length, leaf width, and leaf area occurred under 40% sunlight, whereas the specific leaf area and relative water content increased as light intensity decreased; (2) As light intensity decreased, the total biomass, root biomass, stem biomass, and leaf biomass of seedlings declined, the stem biomass ratio and leaf biomass ratio increased, and the root biomass ratio and root to shoot ratio decreased; (3) The greatest and lowest NSC content occurred under 60% and 5% sunlight, respectively; (4) The specific leaf area was significantly negatively correlated with leaf biomass and NSC content (P < 0.01), whereas leaf biomass had a strong positive correlation with NSC content (P < 0.01). In summary, Chinese fir seedlings might adapt to a shaded environment by adjusting their morphological characteristics to improve their competitive ability and fitness, although seedlings had difficulty maintaining a carbon balance, which led to poor growth and survival, under 5% sunlight.





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