南亚热带常绿阔叶林5种壳斗科植物碳氮磷化学计量特征

壳斗科(Fagaceae)植物是南亚热带常绿阔叶最重要的组成之一,研究其不同树种和器官间碳(C)、氮(N)、磷(P)含量及计量学特征,对于理解和预测树木生态功能的发挥至关重要。以阴那山省级自然保护区同一森林群落中5种壳斗科植物为研究对象,探讨不同树种及器官间C、N、P含量、化学计量及其相关关系特征。结果表明:(1)器官、树种对植物C、N、P含量及化学计量比均会产生一定影响,二者交互作用显著(除C含量),限制程度为器官>树种。(2)从含量上看,5种壳斗科植物凋落物N普遍高于茎、根,而凋落物P则普遍低于茎、根,幼苗叶片N、P含量均低于成熟乔木叶片;黧蒴锥(Castanopsis fissa)根N、N ∶ P高于其他树种,而根P则低于其他树种。(3)从种间变异系数上看,根系N、C ∶ N、N ∶ P变异系数显著高于其他器官;从器官间变异系数上看,黧蒴锥N、C ∶ N变异系数显著低于其他树种。(4)从树种间和器官间的养分相关关系上看,5种植物绝大部分器官元素间两两相关关系不显著,表明单一器官的养分计量关系不能直接反映其他器官或整树水平的计量关系;器官间C和N、C和P相关关系因树种而异,但N和P关系各树种高度一致。综上,从器官上看,根系N含量、C ∶ N、N ∶ P的种间变异系数最大,可能是不同树种对N、P的吸收存在差异,从而有利于物种共存。从树种上看,黧蒴锥具有更合理的养分分配模式,有利于在群落竞争中保持优势地位。

Stoichiometric characteristics of C, N and P of five Fagaceae species in subtropical evergreen broad-leaved forests

Fagaceae plants are one of the most important components of subtropical evergreen broad-leaved forests. To study the carbon (C), nitrogen (N) and phosphorus (P) contents and metrological characteristics of different tree species and organs is of great importance for understanding and predicting the ecological functions of trees. In this study, 5 species of Fagaceae in the same forest community in Yinnashan Provincial Nature Reserve were studied to explore the content, stoichiometry and correlation characteristics of C, N, P among different species and organs. The results showed that: (1) The organ and tree species had certain effects on C, N, P contents and stoichiometric ratio of plants, and the interaction between the two was significant (except C content), and the limiting degree was organ>tree species. (2) In terms of content, litter N was generally higher than that of stem and root, while litter P was generally lower than that of stem and root, and the contents of N and P in the seedling leaves were lower than those in mature tree leaves. The root N and N ∶ P of Castanopsis fissa were higher than those of other species, while the root P was lower than that of other species. (3) From the perspective of interspecific variation coefficient, the variation coefficient of root N, C ∶ N, and N ∶ P was significantly higher than that of other organs; From the point of view of inter-organ variation coefficient, the variation coefficient of N and C ∶ N was significantly lower than that of other species. (4) From the perspective of nutrient correlation between tree species and organs, the correlation between most of the organ elements of the five plants was not significant, indicating that the nutrient metrological relationship of a single organ could not directly reflect the metrological relationship of other organs or the whole tree level; The correlation between C and N, C and P varied with tree species, but the relationship between N and P was highly consistent with each tree species. In summary, from the perspective of organs, the root N content, C ∶ N, and N ∶ P had the largest interspecific coefficient of variation, which may be attributed to the difference in N and P uptake by different tree species, which is conducive to species coexistence. From the point of view of tree species, C. fissa has more rational nutrient distribution pattern, which is conducive to maintaining a dominant position in community competition.