阔叶红松林生态化学计量学特征及其对纬度梯度的响应

为研究红松叶片的养分及生态化学计量学特征的空间分布及其影响因素,依据我国温带阔叶红松林的分布特点,沿纬度梯度,选取长白山(42°27'N)、张广才岭(44°16'N)和小兴安岭(48°05'N)等3个地区的典型阔叶红松老龄林,测定红松叶片碳(C)、氮(N)、磷(P)含量,及表层土壤(0—15 cm)、中层土壤(15—30 cm)的有机碳(SOC)、全氮(TN)和全磷(TP)含量,分析了其分布特征及其相互关系。结果表明:1)红松叶片C、N、P含量显著高于土壤。表层土壤C、N、P含量变化范围分别为27.6—87.4,2.0—7.2 mg/g和0.26—0.92 mg/g;中层土壤为8.1—59.7,0.7—4.6 mg/g和0.2—0.82 mg/g;而叶片为495.5—507.4,12.7—172.5 mg/g和1.1—2.1 mg/g。2)土壤中的SOC、C/N、C/P均随纬度升高极显著增加,而叶片各元素计量特征随纬度的变化不显著。3)叶片N、P含量分别与土壤N、P含量显著正相关,同时,叶片N与土壤C/N、P与土壤N/P显著相关。相比较而言,红松叶片N、P含量较低,这可能说明阔叶红松林土壤N、P供应不足,而叶片N/P仅为9.9,说明东北阔叶红松林N限制更加明显。本研究为阐明东北温带阔叶红松林的养分供应状况和限制因素,为阔叶红松林区提高红松生产力的管理措施的提出奠定了基础。

Characteristics of ecological stoichiometry in broad-leaved and Korean pine mixed forest and its response to latitude gradient in Northeast China

Aims of this study is to explore the spatial distribution of nutrients and the ecological stoichiometry in leaves of Korean pine (Pinus koraiensis Sieb. et Zucc.) and identify the driven factors. According to the distribution range of broad-leaved and Korean pine mixed forest (BKF) in Northeast China, this study sampled 3 sites in Changbai Mountain (42°27''N), Zhangguangcai Mountain (44°16''N) and Xiaoxing''anling Mountain (48°05''N), and measured carbon (C), nitrogen (N) and phosphorus (P) in top soil (0-15 cm), subsurface soil (15-30 cm) and Korean pine leaves, determined spatial variation of nutrient elements along a latitude gradient and the relationships between leaves and soil. The results showed that:1) the contents of C, N and P in leaves were significantly higher than those in soil. The range of C, N, and P in the top (0-15 cm) soil were 27.6-87.4, 0.26-0.92 mg/g, and 2.0-7.2 mg/g, respectively, in subsurface (15-30 cm) soil were 8.1-59.7 mg/g, 0.7-4.6 mg/g, and 0.2-0.82 mg/g, respectively. While, in leaves, were 12.7-172.5 mg/g, 1.1-2.1 mg/g, and 495.5-507.4 mg/g. 2) The organic carbon and C/P and C/N in soil significantly increased along a latitude gradient. The correlation between the elements in leaves and latitude was not significant. 3) Leaves N, P was significantly correlated with total N and P in top soil respectively, additionally, leaves N was significantly correlated with that C/N in top soil, leaves P with N/P in top soil. Comparatively, the contents of N, P in Korean pine leaves are lower than that in natural forest ecosystems along the North-South Transect of Eastern China, which might suggest nutrients supply is not enough to Korean pine growth. Furthermore, low leaves N/P (9.9) indicated N limit is stronger than P in BKF. The results clarify the nutrient supply conditions and their influence factors in BKF, and are helpful to put forward effectively management way to increase forest productivity.