隔离降雨对马尾松针叶非结构性碳水化合物和碳、氮、磷的影响

植物叶片中的非结构性碳水化合物（NSC）和碳（C）、氮（N）、磷（P）含量可反映植物和生态系统对水分亏缺环境的响应及适应程度。以福建省长汀县25a马尾松（Pinus massoniana）为对象，原位观测分析了3年持续100%隔离降雨对成年马尾松针叶NSC与C、N、P的影响。结果表明：（1）持续隔离降雨导致马尾松针叶NSC含量先显著增加后减少，最终导致针叶NSC含量季节变化消失；且针叶可溶性糖含量、可溶性糖/淀粉比值在后期显著增加；（2）持续隔离降雨使马尾松针叶N含量、P含量、N ： P均表现为前期与对照组差异不显著，后期显著高于对照组；（3）马尾松针叶NSC含量、可溶性糖含量、P含量、N ： P与土壤水分含量呈显著或极显著相关，且均与P含量显著或极显著相关，与N素无相关性。以上研究结果表明，随着土壤水分含量的持续减少马尾松可通过调整针叶中NSC含量的积累及分配和提高针叶N、P含量来适应缺水环境，P含量的增加对NSC含量波动及可溶性糖和淀粉的相互转化起促进作用。

Influence of rainfall exclusion on the needle non-structural carbohydrates and C, N, P concentrations in Pinus massoniana

The non-structural carbohydrate (NSC), carbon (C), nitrogen (N) and phosphorus (P) concentrations in plant leaves can reflect the response and adaptation of plants and ecosystems to water-deficit environments. In this study, we analysed the relationship between the NSC, C, N and P in 25a Pinus massoniana needles through in situ observation during a 3-year continuous 100% rainfall exclusion experiment in Changting County, Fujian Province. The results showed that (1) there was no seasonal variation in needle NSC concentrations of the drought group, due to continuous rainfall exclusion; NSC concentrations increased significantly in the early stage and decreased in the late stage; soluble sugar concentration, the ratio of soluble sugar to starch in the drought group increased significantly in the later stage. (2) Compared with the control group, both N and P concentrations as well as the N:P ratio of P. massoniana needles in the drought group showed no significant differences in the early stage and significantly higher values in the later stage. (3) The needle NSC concentrations, soluble sugar concentrations, P concentrations and N:P ratio of P. massoniana correlated significantly or highly significantly with soil moisture content, and all of them were significantly or highly significantly correlated with P concentrations; however, there was no correlation with N concentration. Our findings indicate that P. massoniana could adapt to a continuous reduction in soil water content by adjusting the concentration and distribution of NSC and increasing the N and P concentrations in the needles. Additionally, the P concentration plays a facilitating role in the fluctuation of NSC concentration and the interconversion of soluble sugar and starch.