We compared the interspecific differences in leaf nutrient resorption of two dominant understory species (Lophatherum gracile and Oplimenus unulatifolius), and analyzed the correlations between the intraspecific efficiency of leaf nutrient resorption and nutrient properties of soil and leaves in Chinese fir plantation. The results showed high soil nutrient heterogeneity in Chinese fir plantation. Soil inorganic nitrogen content and available phosphorus content varied from 8.58 to 65.29 mg·kg-1 and from 2.43 to 15.20 mg·kg-1 in the Chinese fir plantation, respectively. The soil inorganic nitrogen content in O. undulatifolius community was 1.4 times higher than that in L. gra-cile community, but there was no significant difference in soil available phosphorus content between the two communities. Both leaf nitrogen and phosphorus resorption efficiency of O. unulatifolius was significantly lower than that of L. gracile under the three measurement bases of leaf dry weight, leaf area, and lignin content. Resorption efficiency in L. gracile community expressed on leaf dry weight was lower than that expressed on leaf area and lignin content, while resorption efficiency expressed on leaf area was the lowest in O. unulatifolius community. The intraspecific resorption efficiency was significantly correlated with leaf nutrient contents, but was less correlated with soil nutrient content, and only the nitrogen resorption efficiency of L. gracile had significant positive correlation with soil inorganic nitrogen content. The results indicated that there was significant difference in the leaf nutrient resorption efficiency between the two understory species. Soil nutrient heterogeneity exerted a weak effect on the intraspecific nutrient resorption, which might be attributed to high soil nutrient availability and potential disturbance from canopy litter in Chinese fir plantation.
本研究以杉木人工林林下优势物种淡竹叶和求米草为对象,比较了2个物种间叶片养分重吸收过程的差异,分析了同一物种内养分重吸收效率与叶片和土壤养分性质之间的关系。结果表明: 杉木人工林土壤养分异质性较高,无机氮和有效磷含量的变化范围分别为8.58～65.29和2.43～15.20 mg·kg-1。求米草群落中土壤无机氮含量为淡竹叶群落的2.4倍,但两者间土壤有效磷含量无显著差异。采用叶片重量、面积和叶片木质素含量作为测算基准,求米草的叶片氮磷重吸收效率均显著低于淡竹叶。对于淡竹叶,基于叶片重量的养分重吸收效率显著低于基于叶片面积和木质素含量的重吸收效率,而对于求米草,基于叶片面积的养分重吸收效率最低。同一物种的叶片氮磷重吸收效率与叶片氮磷含量呈显著正相关,而与土壤氮磷含量的相关性较弱,仅淡竹叶氮重吸收效率与土壤无机氮含量呈显著正相关。研究表明,杉木人工林林下不同植物间叶片养分重吸收效率差异显著,但土壤养分异质性对同一物种不同个体间的养分重吸收影响较弱,这可能归因于杉木人工林较高的土壤养分有效性以及冠层凋落物的潜在干扰。.
Keywords:
Chinese fir plantation;