遮荫对鸡爪槭非结构性碳和化学计量特征的影响

为了探究鸡爪槭（Acer palmatum）的光适应生长策略，测定并分析了不同光照强度（CK、60%光照与40%光照）下鸡爪槭根、枝与叶中非结构性碳积累、分配及其C:N:P化学计量特征。结果表明：随着遮荫程度增加，根的非结构性碳水化合物含量（NSCs）及其组分增大，枝与叶的NSCs及其组分减小，叶N、P含量增大，C:N、C:P减少，枝N含量、N:P先减小再增大，P、C:N和C:P先增大再减小，根N、P含量先增大再减小，N:P、C:N和C:P先减小再增大。在全光照下，NSCs及其组分为叶>枝>根，N含量为叶>根>枝，N:P和C:N为根>叶>枝；60%的光照下，NSCs及其组分为叶>枝>根，N含量与N:P为叶>根>枝，C:N与C:P为枝>叶>根；40%光照下，NSCs及其组分根>叶>枝，N、P含量为叶>枝>根，C:N与C:P为根>枝>叶。相关性分析表明，叶可溶性糖、淀粉、NSCs含量与N、P含量呈显著负相关，与C:N和C:P呈显著正相关（P < 0.01）；枝NSCs含量与N和C:N呈显著负相关（P < 0.05），根NSCs与C:N呈显著正相关（P < 0.05），枝SS:ST与N、N:P与C:N呈极显著负相关（P < 0.01）。由此可见，随着光照强度的降低，鸡爪槭通过增加根系NSCs积累与分配，保证根系的存活以及提高叶片N、P含量的策略来适应荫蔽环境。

Effects of shading on non-structural carbon and stoichiometric characteristics of Acer palmatum

In order to explore the light adaptive growth strategy of Acer palmatum, the accumulation, distribution and C:N:P stoichiometric characteristics of non-structural carbon in roots, branches and leaves of A. palmatum under different light intensities (CK, 60% light and 40% light) were measured. The results showed that the content of non-structural carbohydrate and its components in roots increased with the increase of shading degree, while NSCs and their components in branches and leaves decreased, N and P contents in leaves increased, C:N and C:P decreased, N and N:P contents in branches decreased first and then increased, P, C:N and C:P increased first and then decreased, N and P contents in roots increased first and then decreased, and N:P, C:N and C:P decreased first and then increased. Under full light, NSCs and their components were leaf > branch > root, N content was leaf > root > branch, N:P and C:N were root > leaf > branch; under 60% light, NSCs and their components were leaf > branch > root, N content and N:P were leaf > root > branch, C:N and C:P were branch > leaf > root; under 40% light, NSCs and their components were root > leaf > branch, N and P contents were leaf > branch > root, C:N and C:P were root > branch > leaf. The correlation analysis showed that the contents of soluble sugar, starch and NSCs in the leaves were negatively correlated with the contents of N and P, and positively correlated with the contents of C:N and C:P(P < 0.01); NSCs content in the branches was negatively correlated with N and C:N(P < 0.05), NSCs in the roots were positively correlated with C:N(P < 0.05), and SS:ST in the branches were negatively correlated with N, and N:P were negatively correlated with C:N(P < 0.01). Therefore, with the decrease of light intensity, A. palmatum adapts to the shade environment by increasing the accumulation and distribution of NSCs in the roots, ensuring the survival of the roots and increasing the contents of N and P in the leaves.