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林下植被稀少及分布单一是造成红壤区马尾松林下水土流失的主要原因,且与林木的化感作用存在密切联系。本文以马尾松和枫香为研究对象,通过生物检测等技术手段,分析其根际土壤提取物对狗牙根、白三叶、巴哈雀稗和早熟禾的化感作用类型及强度差异。结果表明:(1)1、0.5和0.25 mg·m L-13种浓度下马尾松根际土壤提取物对4种受体植物均表现为明显的化感抑制综合效应,在0.5和0.25 mg·m L-1浓度下枫香根际土壤提取物也表现为抑制效应,但这种抑制效应低于马尾松根际土壤,在1 mg·m L-1浓度下却呈现出一定的促进作用;(2)马尾松根际土壤提取物主要包括浓度效应不明显(狗牙根)和随浓度升高抑制效应增强(白三叶、巴哈雀稗和早熟禾)2种类型,而枫香根际土壤提取物主要包括低促高抑(狗牙根)、高促低抑(白三叶和早熟禾)和随浓度升高抑制效应增强(巴哈雀稗)3种类型。因此,从化感作用角度探讨马尾松纯林与混交林林下植被组成和分布差异的成因,为解释马尾松林下植被匮乏及分布单一现状、进行林相结构改造和遏制土壤侵蚀提供了新思路。
The understory vegetation and the single distribution are the main causes of water and soil loss under Pinus massoniana forest in red soil area, and are closely related to the allelopathy of forest trees. In this paper, Masson pine and Liquidambar formosuperides were selected as the research object. The allelopathy types and intensities of rhizosphere soil extracts on bermudagrass, white clover, paspalum and bluegrass were analyzed by bioassay and other techniques. The results showed that: (1) The rhizosphere soil of Pinus massoniana at 1, 0.5 and 0.25 mg · m L-1 concentrations showed significant allelopathic inhibitory effects on all four plant species. At 0.5 and 0.25 mg · m The soil Rhizosphere extract of Liquidambar formosum also exhibited inhibitory effect at L-1 concentration, but the inhibitory effect was lower than that of rhizosphere soil of Pinus massoniana at 1 mg · m L-1 concentration. (2) ) Pinus massoniana rhizosphere soil extracts mainly include two kinds of types, the concentration effect is not obvious (bermudagrass) and enhanced with increasing concentration inhibition (white clover, barnyard grass and Kentucky bluegrass), but Liquidambar formosolic rhizosphere soil extract Mainly include low and high inhibitory (bermudagrass), high and low inhibition (white clover and bluegrass) and inhibitory effect with increasing concentration (barnyard grass) three types. Therefore, from the perspective of allelopathy, the reasons for the differences in the composition and distribution of understory vegetation in pure Pinus massoniana and mixed forest were discussed. The results provided a new idea for explaining the lack and distribution of understory vegetation in Pinus massoniana forest, rebuilding forest structure and controlling soil erosion.