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玉米千秆还田对小麦根部病害的化感作用研究

标题: 玉米千秆还田对小麦根部病害的化感作用研究
英文标题: Study on Allelopathy of Maize Straw Retention on Root Disease of Wheat
作者: 张承胤
出版时间: 2007-01-01
所在大学: 河北农业大学
关键词: 玉米秸秆还田,玉米秸秆腐解液,小麦根部病害,化感作用
英文关键词: Maize straw retention,Maize straw decomposed liquid,Root diseases of wheat,Allelopathy
论文级别: 硕士
学位: 学位论文
导师: 甄文超
专业: 植物病理学
提交时间: 2007
摘要: 在中国北方小麦-玉米两熟种植制度下,大量玉米秸秆连年还田对麦田土壤生态系统已表现出显著影响,但近年来发现秸秆还田地块小麦根部病害发生日趋加重.还田玉米秸秆在土壤微生物的作用下会腐解释放出多种化学物质,对小麦根系生长发育及根部病害病菌产生化感作用.本研究在室内盆栽和大田小区条件下研究了玉米秸秆还田对小麦根部病害的化感作用及其作用机理,并筛选了适应玉米秸秆还田的小麦根病拮抗微生物.结果表明:玉米秸秆腐解液对小麦生长发育具有抑制作用,主要表现在:不同浓度腐解液抑制小麦种子萌发、根干重增加,且随腐解液浓度增加抑制作用增强,高浓度腐解液对小麦幼苗株高、茎叶干重的抑制作用较强,小麦幼苗根系活力随玉米秸秆腐解液浓度增高而降低.不同时期提取的腐解液对三种小麦根病病原菌菌丝生长具有不同程度的抑制作用,以7d时提取的玉米秸秆腐解液作用最强,同一时期提取的腐解液对病菌的抑制作用随腐解液浓度增大而增强.利用高效液相色谱在玉米秸秆腐解液中检测到了对羟基苯甲酸、苯甲酸、丁香酸、邻苯二甲酸、香草酸.玉米秸秆还田对小麦生长发育及根系活力等生理指标等有一定影响.盆栽试验发现大量玉米秸秆处理可抑制小麦根系SOD酶活性和根系活力,提高PPO酶活性.田间小区试验中发现倍量秸秆还田处理对小麦根系活力、SOD酶、MDA含量有一定的抑制作用,同时增加根系相对电导率,对小麦根系生长产生一定的抑制作用,表现在小麦植株外部特征上即大量秸秆还田可减少小麦冬前基本苗数,降低小麦幼苗株高、茎叶干重、根系干重.玉米秸秆还田后可增加麦田土壤中真菌、细菌和放线菌的数量,土壤微生物不同类群增长趋势是细菌>放线菌>真菌;秸秆还田作用强度上是全量秸秆还田处理>倍量秸秆还田处理>半量秸秆还田处理.在对小麦根部病害的模拟研究中发现玉米秸秆腐解液对三种小麦根部病害的发生影响不同.大田试验结果表明倍量秸秆还田处理、全量秸秆还田处理可不同程度地加剧小麦纹枯病、小麦根腐病和小麦全蚀病的发生.经平板对峙培养法从玉米秸秆还田土中筛选得到对小麦全蚀病、小麦根腐病、小麦纹枯病都有防效的拮抗细菌19株,结合其对玉米秸秆性降解性能,发现菌株F1514即对小麦根病具有较强的拮抗作用,又对玉米秸秆具有一定的分解能力和适应性.
英文摘要: Under the condition of "wheat-maize" rotation system in north of China, obviouseffects were present in the wheat field ecosystem caused by amounts of maize strawretention in long term. However, root diseases of wheat (Wheat Take-all, Wheat SharpEyespot and Wheat Common Rot) in the maize straw retention field became seriouscurrently. Many allelochemical, released with the degradation of maize straw bymicroorganism, would enhance allelopathy on the growth of wheat and root diseases ofwheat. The allelopathy and mechanism of maize straw retention on the growth of wheatand root diseases of wheat were studied under different conditions such as pot trial andfield trial. Antagonistic microorganism adapted to maize straw retention was selected. Theresults were summarized as follows:Maize straw residue was decomposed under laboratory conditions, and filtered atdifferent time. The decomposed liquid was tested for bioassay. It was found that allconcentrations of decomposed liquid suppressed the germination of wheat seeds and dryweight of root, and the inhibition effect was strong when the concentration of decomposedliquid was high. High concentration of maize straw decomposed liquid also showed theinhibitory effects on height of wheat, dry weight of stem and leaf. Dry weight of rootdecreased by 57.53%and 37.49%respectively at the concentration of 0.50g DW/mL and0.25g DW/mL at 45d. Root activity in TTC reduction of wheat became low when theconcentration of decomposed liquid ranged from low to high. The maize strawdecomposed liquid filtered at different time showed different inhibition effects to the threepathogenic fungi of Rhizoctonia cerealis Vander Hoeven, Gaeumannomyces graminis(Sacc.) Arx et Oliver and Bipolaris sorokiniana (Sacc.) Shoem., For the decomposed liquidfiltered at the same time, the inhibition effect became strong while the concentration washigh.ρ-hydrobenzoic acid, pathalic acid, benzoic acid, syringic acid, vanllic acid weredetected in maize straw decomposed liquid by using HPLC.Growth of wheat and physiological activity of wheat root were affected by maizestraw retention. The result (pot trial)showed that maize straw treatments (maize straw:fieldsoil=30g: 1kg) can decrease the root activity in TTC reduction and SOD activities, increasePPO activities of wheat root to some degree. DR (15000kg/hm2 maize straw incorporated)treatment in field trial also showed the inhibition to TTC reduction, SOD activities, root lipid peroxidation of wheat root system and growth of wheat, enhanced root electrolyteleakage. A mass of maize straw retention can decrease the amount of wheat seedling beforewinter and at re-greening stage, plant height of wheat seedling, dry weight of leaf and stem,dry weight of root.Maize straw retention increased the quantity of soil bacteria, fungi and actinomycete,and bacteria>actinomycete>fungi. The trend was WR>DR>HR in efficacy ofmicroorganism quantity increasing (DR:15000kg/hm2 maize straw retention; WR:7500kg/hm2 maize straw retention; HR:3750kg/hm2 maize straw retention).Maize straw decomposed liquid had no impact on presence of wheat root diseases inthe simulation of allelopathy in maize straw retention. The result of field trial showed thatDR treatment and WR treatment could increase the happening of Wheat Common Rot,Wheat Sharp Eyespot and Wheat Take-all in the condition of "wheat-maize" rotationecosystem.19 bacteria strains, isolated from maize straw retention field, had inhibition effect tothe three pathogenic fungi of wheat root diseases, and then were tested by the trial ofdegradation and adaptation activity of maize straw. Only 1 strain had high inhibitionefficacy and adaptation to maize straw.