兴安落叶松(Larix gmelinii Rupr.)叶片养分的空间分布格局

Spatial patterns for variations in leaf nutrient contents of Dahurian Larch(Larix gmelinii Rupr.)

对中国东北温带森林生态系统主要树种兴安落叶松(Larix gmelinii Rupr.)24个采样点72个叶片样品有机碳(C)、全氮(N)、全磷(P)和全钾(K)的化学组成、地理分布格局及其与气候因子的关系进行了研究。结果表明,叶片C、N、P和K含量的几何平均数分别为543.970、16.902、2.373mg/g和14.625mg/g,且叶片的C含量>N含量>K含量>P含量;叶片的C/N、C/P和N/P分别为32.183、229.226和7.123。随纬度的增加、年均温度和年均降雨量的降低,兴安落叶松叶片C、N含量和N/P显著降低,叶片C/N和K含量显著升高,叶片P含量和C/P的变化没有达到显著水平。叶片N含量随纬度与年均温度的变化与全球及其它大尺度的研究结果相反,而N/P与其一致,这与在该区域的其它物种的研究结果基本一致。这可能是由于在本研究区域北部寒温带越往高纬度地区年均温度和年均降雨量越低、生长季越短,因此成土作用弱导致植物可以吸收利用的养分越少,但是由于植物显著降低的N含量和变化不明显的P含量导致了叶片N/P随纬度的增加和年均温度和年均降雨量的降低而降低,这与全球尺度的研究结果一致。兴安落叶松叶片养分分布格局与全球尺度和中国区域研究结果的差异说明了加强区域叶片养分特征研究的重要性。叶片养分与气候因子的显著线性相关说明气候因子是影响叶片养分特征的一个主要因子。

Spatial patterns for leaf nutrient contents of Dahurian larch（Larix gmelinii Rupr.）based on the analysis of 72 samples in 24 sites in temperate forest ecosystems in Northeast China were studied.The studied region belongs to the cold temperate zone.The results show that the geometric means of leaf organic carbon（C）,nitrogen（N）,potassium（K）and phosphorus（P）contents were 543.970 mg/g,16.902 mg/g,14.625 mg/g and 2.373 mg/g,respectively.The geometric means of C/N,C/P and N/P were 32.183,229.226 and 7.123,respectively.With the increase of latitude and decrease in mean annual temperature（MAT）and annual precipitation（AP）,leaf C and N contents and N/P ratios of Dahurian larch decreased significantly,and leaf C/N ratios and K content increased significantly,but leaf P contents had no significant change.The changes in the leaf N content with latitude,MAT and AP are different from those reported in literature,but the changes in the leaf N/P ratio are similar to those in literature,which are similar to the changes of other species in our studied region.With the increase in latitude,MAT and AP decreased,and the growing season shortened,pedogenesis was weakened and available soil nutrients for plant decreased,but N/P ratios decreased significantly because of the significant decrease in N content.This finding is similar to the results obtained in other global observations.The differences in the spatial patterns of foliar nutrient contents between Dahurian larch and global and other Chinese flora indicate the importance of an advanced understanding of leaf traits in terms of nutrient contents in a regional scale.The significant relationships between leaf nutrient contents and climatic factors suggest that climatic factors are the major forces affecting variation in the leaf nutrient traits of Dahurian larch.