蚯蚓缓解草莓连作障碍的效应及机理研究

发布时间：2018-05-05 04:39

  本文选题：蚯蚓 + 连作障碍　； 参考：《中国农业大学》2016年博士论文

【摘要】：蚯蚓是土壤中重要的动物,其对植物生长有促进作用。然而,蚯蚓对连作系统种植的作物生长和病害的影响及机理尚不清楚。如果能够利用蚯蚓自身特点,来缓解作物连作障碍,具有重要的意义。本研究以连作草莓为例,通过接种蚯蚓,利用盆栽实验及微宇宙实验,对蚯蚓缓解连作障碍的效应进行了研究,并从蚯蚓对化感物质的降解以及对微生物群落的调控入手,揭示了蚯蚓缓解连作障碍的机理,主要研究结果如下：(1)蚯蚓能够促进连作草莓的生长,提高草莓的生物量和产量,并能显著降低由尖孢镰刀菌引起的枯萎病(P0.05)。在盆栽条件下,威廉腔蚓和赤子爱胜蚓可使病情指数降低至11.8和27.7,而对照组病情指数为50.9。(2)蚯蚓的作用,加速了连作土壤中的酚类物质的降解。蚯蚓具有回避土壤中较高浓度酚酸(大于120μgPA/g)的特点,但是这种行为可以通过添加叶片抵消。另外,蚯蚓降解酚类物质的能力与蚯蚓种、蚯蚓密度、以及酚类物质的来源有关。威廉腔蚓降解酚类物质的效率要高于赤子爱胜蚓：当威廉腔蚓的密度达到300条/m2时,降解效率最高；与根系腐解产生的酚类相比,叶片腐解产生的酚类更利于被蚯蚓降解。(3)蚯蚓对酚类物质的降解是通过对微生物的调控实现的,当土壤灭菌后,蚯蚓本身不能降解酚类物质。蚯蚓的活动加速了酚类物质降解过程中微生物的演替进程,提高了降解过程中微生物的活性和多样性,最终加快了酚类物质的降解。(4)蚯蚓对于土壤中不同的酚酸降解效果不同,蚯蚓活动一方面加速了总酚的降解,另一方面加快了对香豆酸、绿原酸等草莓连作土壤中浓度较高的酚酸的降解,而对于另外一些酚酸,其降解效果并不显著。因此蚯蚓的活动改变了土壤中酚酸的比例。(5)草莓连作系统中蚯蚓的活动,提高了微生物量、微生物的活性以及微生物的多样性,微生物这些性质的改变,有利于土壤生态系统稳定性提高,进而提高了生态系统的抗病功能。同时,蚯蚓的活动,也提高了某些病原菌拮抗菌的比例,也有利于防控草莓的病害。(6)蚯蚓对于连作草莓主要有两方面的作用：一方面是直接调控连作土壤微生物的群落结构,提高微生物的多样性和活性,以及某些有益微生物的比例,从而提高根际区土壤的抑病能力；另一方面是其活动加快了某些化感物质的降解,尤其是草莓连作土壤中积累浓度较大的酚酸,而这些酚酸具有抑制植物生长、促进病原菌并破坏微生态平衡的特性,因此,蚯蚓对酚酸的降解间接地促进了植物的生长,提高了植物的抗病性。另外,蚯蚓这两方面的作用也是相互影响的,降解酚酸有利于恢复微生态平衡,而调控微生物也有利于酚酸的降解,综合作用的结果缓解了草莓的连作障碍。
[Abstract]:Earthworms are important animals in soil, which can promote plant growth. However, the effects and mechanisms of earthworms on crop growth and disease in continuous cropping system are unclear. It is of great significance to use the characteristics of earthworms to alleviate crop continuous cropping obstacles. By inoculating earthworm, pot experiment and microcosmic experiment, the effects of earthworm on alleviating the obstacle of continuous cropping were studied, and the degradation of allelochemicals and the regulation of microbial community by earthworm were studied in this study. The main results are as follows: (1) Earthworm can promote the growth of continuous cropping strawberry, increase the biomass and yield of strawberry, and significantly reduce Fusarium oxysporum wilt caused by Fusarium oxysporum. Under the condition of pot culture, the disease index was decreased to 11.8 and 27.7, while the disease index of the control group was 50.9.22), which accelerated the degradation of phenols in continuous cropping soil. Earthworms have the characteristic of avoiding higher concentration of phenolic acid (> 120 渭 g PA / g) in soil, but this behavior can be counteracted by adding leaves. In addition, the ability of earthworms to degrade phenolic substances is related to earthworm species, earthworm density and sources of phenolic substances. The efficiency of degradation of phenolic substances by the worm was higher than that of Aisheng vermis. When the density of the worm reached 300 / m2, the degradation efficiency was the highest, compared with the phenol produced by root decomposition. The phenols produced by leaf decomposition are more favorable to be degraded by earthworms.) the degradation of phenolic substances by earthworms is realized through the regulation of microbes. When soil sterilizes, earthworms cannot degrade phenols themselves. The activities of earthworms accelerated the process of microbial succession during the degradation of phenolic substances, increased the activity and diversity of microorganisms in the degradation process, and finally accelerated the degradation of phenolic substances. 4) the effects of earthworms on the degradation of phenolic acids in soil were different. Earthworm activity accelerated the degradation of total phenol on the one hand, and on the other hand accelerated the degradation of phenolic acid in strawberry continuous cropping soils such as coumaric acid and Lv Yuan acid, but the degradation effect of other phenolic acids was not significant. Therefore, earthworm activity changed the proportion of phenolic acid in soil. 5) earthworm activity in strawberry continuous cropping system increased microbial biomass, microbial activity and microbial diversity. The stability of soil ecosystem was improved and the disease resistance function of soil ecosystem was improved. At the same time, the activity of earthworms also increased the proportion of antagonistic bacteria of some pathogens, and was also beneficial to the prevention and control of strawberry diseases. The earthworm had two main effects on continuous cropping strawberry: on the one hand, it directly regulated the community structure of microbes in continuous cropping soil. Increasing the diversity and activity of microbes, as well as the proportion of certain beneficial microbes, thereby increasing the ability of rhizosphere soils to suppress disease; on the other hand, their activities accelerate the degradation of certain allelochemicals, Especially the accumulation of phenolic acids in strawberry continuous cropping soil, which has the characteristics of inhibiting plant growth, promoting pathogenic bacteria and destroying microecological balance. Therefore, the degradation of phenolic acids by earthworms indirectly promotes the growth of plants. The disease resistance of plants was improved. In addition, the role of earthworm in these two aspects is also mutual, the degradation of phenolic acid is conducive to restore the micro-ecological balance, while the regulation of microorganisms is also conducive to the degradation of phenolic acid.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S668.4;S154.5
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本文编号：1846254