宁夏贺兰山青海云杉林藓类植物C∶N∶P化学计量特征

C:N:P stoichiometric characteristics of mosses in Picea crassifolia forest in Helan Mountains,Ningxia,China

为探究山地森林生态系统藓类C、N、P化学计量学特征及适应机制,本研究沿海拔梯度在宁夏贺兰山青海云杉林设置15个样地,分析藓类地上组织C∶N∶P化学计量特征及其与环境因子的关系。结果表明:藓类植物地上组织C、N、P含量与海拔无关,且均值分别为336.67、20.31和0.66 mg·g^(-1);地上组织N∶P均值为33.4,说明藓类植物生长受P限制。藓类植物地上组织中C含量与土壤全氮含量呈显著正相关,与土壤全磷含量呈显著负相关;藓类植物地上组织中N含量与土壤有机碳和土壤全氮含量均呈显著负相关。冗余分析表明,环境因子对藓类地上组织化学计量特征的解释率为48.5%,主要环境影响因子为郁闭度、土壤全氮、土壤全磷;高郁闭度对藓类植物的生长具有促进作用。

To explore the stoichiometric characteristics of C,N and P and adaptive mechanism of mosses in mountain forest ecosystems,we set up 15 plots along the altitude gradient in Picea crassifolia forest in Helan Mountains,Ningxia.We analyzed the C:N:P stoichiometry of moss aboveground tissues and its relationship with environmental factors.The results showed the mean values of C,N and P concentration in moss aboveground tissues were 336.67,20.31 and 0.66 mg·g^(-1),respectively.The mean value of aboveground tissue N:P was 33.4,indicating that the growth of mosses was limited by P.The C concentration in the aboveground tissues of mosses was positively correlated with soil total nitrogen concentration and negatively correlated with soil total phosphorus concentration.The N concentration in aboveground tissues of mosses was significantly negatively correlated with soil organic carbon and soil total nitrogen concentrations.Results of redundancy analysis showed that the interpretation rate of environmental factors on the stoichiometry was 48.5%,with canopy closure,soil total nitrogen and soil total phosphorus as the main factors.Canopy closure was the main environmental factor affecting the growth of mosses in P.crassifolia forest in Helan Mountains.High canopy closure facilitated the growth of mosses.