【作者】 李瑞华；

【导师】 朱建兰；

【作者基本信息】 甘肃农业大学 ， 植物病理学， 2009， 硕士

【摘要】 本论文主要对红豆草根际分泌物的化感作用、化感物质的提取分离、根系分泌物与根际微生物以及化感作用机理进行了系统的研究,旨在充分利用植物间的化感作用防除农田杂草,为开发天然除草剂,有效合理利用资源,发展可持续农业提供理论依据。主要结果如下:1.红豆草根系分泌物对7种受体植物化感效应的测试利用组织培养技术提取红豆草根系分泌物,并运用生物学测定的方法研究了红豆草根系分泌物对7种受体植物的化感作用。得出红豆草根系分泌物对7种受体植物种子萌发、幼苗根长和苗高等均有一定的抑制作用。结果表明:同一受体植物对不同处理浓度的敏感效应不同,随处理浓度的升高,红豆草根系分泌物对7种受体植物种子萌发的抑制作用越明显,当浓度为100mg·ml-1时抑制作用最大;且同一处理浓度对不同的受体也表现出一定的种间差异,从四个处理浓度的平均抑制率综合来看,红豆草根系分泌物对灰藜、稗草、反枝苋、黑麦草的抑制作用相对较强,平均抑制率分别为灰藜62.72%,稗草53.79%,反枝苋51.43%,黑麦草51.43%,对龙葵、高羊茅、狗尾草的的抑制作用相对较弱,且红豆草根系分泌物对受体植物幼根的化感抑制作用强于茎叶。2.红豆草根系分泌物对根际微生物的影响细菌是红豆草根际微生物的优势类群,其主要分布在10-20cm的耕作层,真菌、细菌、放线菌总数均在8月份土壤平均温度最高时达到最大值;而且三年生红豆草田土壤微生物总量大于二年生和一年生的红豆草田,且有细菌总量>放线菌总量>真菌总量。3.红豆草根系分泌物对七种受体植物化感抑制作用的机理研究测定了不同浓度的红豆草根际分泌物对受体植株体内几种酶活性的影响:红豆草化感物质降低了受体体内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)等抗性酶的活性和可溶性蛋白质(Pr)含量,使受体植物对外界不良环境的抵抗力降低,受体植物的生长发育受到抑制,从而表现出强烈的克生能力。更多还原

【Abstract】 Allelopathy, Allelochemicals、rhizosphere microorganisms and Allelopathic Mechanism of Sainfoin root exudates have be studied on this experiment. For to use the Allelopathy of plant to control the weeds in agriculture, to exploit the new natural herbicide, to utilize natural resources more effectively and sensibly, and for to develop sustained agriculture theory. The results as follows:1. The test of the sainfoin root excudation’s allelopathy effect to seven receptor plantsUsing tissue culture, exudation was extracted from sainfoin’s root, and studied exudates’allelopathy effect to the seven plants by biological assay. Sainfoin root exudates had inhibition on root germination, seedling root growth and plant height. The results showed that the same receptor plant had different sensitive effect for the different treatment concentration.The inhibition of sainfoin root exudates gradually significantly for the root germination of seven receptor plants, and the inhibition effect was maximum when concentration was 100mg·ml-1; and the same treatment concentration had definitely Interspecific difference. The average inhibition rate of four treatment concentration showed that sainfoin root exudates had stronger inhibition to ash pigweed, annual bluegass, amaranthus, rye grass, the aveage inhibition were respectively 62.72%, 53.79%, 51.43%,51.43%; but the inhibition was weaker to Nightshade, tall fescue, bristlegrasses. And sainfoin root exudates had stronger inhibition effect to plant radicle than stems and leaves.2. Sainfoin root exudates affected rhizosphere microorganismsbacteria was predominant group of sainfoin rhizosphere microorganisms, its mainly distruibuted 10~20cm cultivated horizon. Fungi, bacteria, actinomycetes reached maximum in august when the average temperature of soil was highest. And the total soil microorganism of the triennial sainfoin land were more than biennial and annual land; and the total bacteria >the total actinomycetes>the total fungi.3. The mechanism of allelopathic inhibiting effect to seven receptor plants from sainfoin root exudates. Determined Sainfoin root exudates affected some enzymes in seven receptor plants with different concentration. The result indicated that the activity of the hyperoxide mutase (SOD), the peroxide enzyme(POD), the catalase (CAT),ascorbate peroxidase (APX) and soluble protein content (Pr)were decreased by allelochemicals of sainfoin root exudates. These enzymes cut down the resistance and inhibited the growth of receptor plants. As a result it showed strong allelopathic ability.更多还原