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应用生态学报 ›› 2020, Vol. 31 ›› Issue (7): 2175-2184.doi: 10.13287/j.1001-9332.202007.003

• 植物化感作用专栏 • 上一篇    下一篇

不同密度巨桉人工林林下植物多样性及根际土壤化感物质

李金金, 张健, 张阿娟, 吴娇, 张丹桔*   

  1. 四川农业大学生态林业研究所林业生态工程省级重点实验室, 成都 611130
  • 收稿日期:2020-01-01 接受日期:2020-03-28 出版日期:2020-07-15 发布日期:2021-01-15
  • 通讯作者: E-mail: zdj_8080573@sohu.com
  • 作者简介:李金金, 女, 1993年生, 博士研究生。主要从事森林培育研究。E-mail: jjl_0907@126.com
  • 基金资助:
    国家自然科学基金项目(31770671)资助

Understory plant species diversity and allelochemicals in rhizosphere soils of Eucalyptus grandis plantations with different densities

LI Jin-jin, ZHANG Jian, ZHANG A-juan, WU Jiao, ZHANG Dan-ju*   

  1. Key Laboratory of Ecological Forestry Engineering in Sichuan Province, Institute of Ecology and Forestry, Sichuan Agricultural University, Chengdu 611130, China
  • Received:2020-01-01 Accepted:2020-03-28 Online:2020-07-15 Published:2021-01-15
  • Contact: E-mail: zdj_8080573@sohu.com
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (31770671).

摘要: 为探究巨桉人工林林下植物多样性的影响因素,选择四川省丹棱县4和8年生不同密度(1200、1600和2000株·hm-2)巨桉人工林为对象,研究林下植物多样性和根际土壤酚类化感物质。结果表明: 共发现植物45种,隶属于33科44属;随林龄增加和林分密度降低,巨桉人工林林下植物种类增加且重要值分布更为均匀;各林分植物生活型以高位芽植物为主。4年生林地灌木Shannon指数和Margalef指数在1600株·hm-2下显著升高,4年生林地除Margalef指数外其余草本多样性指数及8年生林地草本Pielou指数随林分密度降低均显著升高;灌木Shannon指数及Margalef指数在1200株·hm-2下8年生林地显著高于4年生林地。根际土壤中鉴定出5种酚类化感物质,4年生林地根际土壤中水杨酸浓度在1600株·hm-2下显著降低,5,7-二羟基黄酮浓度随林分密度降低而显著降低;水杨酸浓度在8年生林地根际土壤中随林分密度降低显著升高;水杨酸浓度在2000株·hm-2下4年生林地显著高于8年生林地,在1600株·hm-2下相反;5,7-二羟基黄酮浓度在1200株·hm-2下8年生林地显著高于4年生林地。冗余分析(RDA)结果表明,土壤pH、容重、有机质、全磷、全氮及化感物质是林下植物多样性的主要环境影响因子。适度延长轮伐期、调节林分密度以改善林内微环境、缓冲巨桉的化感作用,可促进林下植被发育。

关键词: 巨桉人工林, 造林密度, 植物多样性, 酚类化感物质

Abstract: To explore the influencing factors of understory plant species diversity of Eucalyptus grandis, we examined understory plant species diversity and phenolic allelochemicals in the rhizosphere soils of four-year-old and eight-year-old E. grandis plantations with different densities (1200, 1600, 2000 ind·hm-2) in Danling County of Sichuan Province. The results showed that a total of 45 plant species were recorded, belonging to 33 families and 44 genera. With the increases of stand age and decreases of stand density, plant species richness increased and their importance values were evenly distributed. Phanerophytes was the dominant life form across all stands. Shannon index and Margalef index of shrub in the four-year-old E. grandis plantations increased significantly at the density of 1600 ind·hm-2. All herbage plant diversity index except for Margalef index in four-year-old ones and Pielou index in eight-year-old plantations increased significantly with the decreases of density. Shannon index and Margalef index of shrub in 1200 ind·hm-2 were significantly higher in eight-year-old E. grandis stands than those in four-year-old ones. Five phenolic allelochemicals in the rhizosphere soils of E. grandis plantations were identified. In four-year-old stands, salicylic acid concentrations decreased significantly at the density of 1600 ind·hm-2. The concentrations of chrysin in four-year-old stands reduced significantly with the decreases of density. The concentrations of salicylic acid in eight-year-old stands increased significantly with the decreases of tree density. Salicylic acid concentrations in 2000 ind·hm-2 were significantly higher in four-year-old stands than that in eight-year-old ones, but the result was opposite in stands with density of 1600 ind·hm-2. The concentrations of chrysin in stand with density of 1200 ind·hm-2 were significantly higher in eight-year-old stands than that in four-year-old ones. Rundancy analysis (RDA) result showed that soil pH, bulk density, and the concentrations of soil organic matter, total nitrogen, total phospho-rus, and allelochemicals were the main environmental factors influencing understory plant species diversity. Therefore, prolonging rotation period and reducing stand density would improve micro-environmental condition of forests and buffer the allelopathy of E. grandis, which could facilitate the development of understory vegetation.

Key words: Eucalyptus grandis plantation, stand density, plant diversity, phenolic allelochemicals