关键词: 长期施肥, 红壤性水稻土, 土壤有机碳含量, 土壤有机碳储量

Abstract: By substituting spatial difference for temporal change, this paper studied the morphological variation patterns of Lithocarpus glaber seeds in evergreen broadleaved forest during the succession of plant communities in Gutian Mountain of Zhejiang Province, and the redundancy analysis (RDA) was adopted to analyze the relationships between the seed morphological characteristics and ecological factors. The results indicated that succession stage explained the majority of the variation of the seed morphology (P<0.001), elevation was ranked as the second (P<0.001), while slope had minor effects on the variation. With the succession of the plant communities, the coefficients of variation of the L. glaber seed length, seed diameter, and seed volume all increased significantly (P<0.001). Furthermore, the proportion of the second grade seeds declined with succession, while the proportions of the first grade seeds and third grade seeds increased steadily, resulting in the polarization of seed size at the late succession stage. The proportion of empty seeds increased gradually with succession, leading to the significantly higher empty seed percentage at middle succession stage than at early succession stage (P<0.001), and also, at late succession stage than at middle succession stage (P<0.001). It was speculated that the morphological variation of L. glaber seeds could be attributed to the changes in the light environment and community structure during the process of succession. Further analysis revealed that the seed morphological characters of L. glaber at the late succession stage of plant communities could lead to the severe regeneration barrier for L. glaber, which might explain the observed regeneration failure of this species.

Key words: long-term fertilization, red paddy soil, SOC content, SOC storage.