【作者】 刘素慧；

【导师】 刘世琦；

【作者基本信息】 山东农业大学 ， 蔬菜学， 2011， 博士

【摘要】 随着人口的快速增加和社会经济的发展,人们对一些特定的农作物产品需求量日益增加,使现代农业呈现出单一作物大面积种植的特点。作为一种普遍发生的农业现象,连作障碍对许多国家的农、副业造成极大的危害。大蒜(Allium sativum L.)是深受世界各国人民喜爱的保健蔬菜,又是重要的调味品和医药原料,也是中国重要的加工原料和出口创汇蔬菜。随着大蒜生产的不断发展,大蒜主产区的连作现象日益严重。本研究从大蒜根系分泌物和秸秆水浸液的化感作用、连作对大蒜根际土壤微生态环境(土壤可培养微生物和土壤酶活性)以及产量和品质的影响、施加EM菌剂缓解大蒜连作障碍三个方面对大蒜连作障碍问题进行了研究,以期为探讨大蒜连作障碍形成机理和缓解大蒜连作障碍问题提供科学依据,主要研究结果如下:1.短期连作(5年和10年)大蒜根际土壤细菌、放线菌和各生理类群数量急剧增加,真菌数量缓慢增加,土壤酶活性逐渐上升,微生态环境向良性方向发展,大蒜产量和品质也显著增加;但连作15年和20年大蒜根际土壤细菌、放线菌和各生理类群数量下降,真菌数量增加,土壤酶活性降低,土壤微生态环境呈变劣趋势,大蒜产量和品质也随之显著下降,连作障碍较为明显。2.通过组培法得到的大蒜根系分泌物对大葱、洋葱和韭菜等同属作物种子萌芽和生长均有抑制作用,抑制程度随着大蒜根系分泌物浓度的增大而加大。GC-MS鉴定大蒜根系分泌物中的主要物质有2,2’-亚甲基双(4-甲基-6-叔丁基基)苯酚、邻苯二甲酸二辛酯、5-辛基巴比妥酸、花生酸、阿魏酸、9-十六稀酸、肉豆蔻酸、二烯丙基二硫化物等。3.大蒜秸秆水浸液对番茄、辣椒、黄瓜胚芽和胚根的影响表现为低浓度促进,高浓度抑制;试验设计浓度均抑制番茄和辣椒种子发芽率,但对黄瓜种子的发芽率无明显影响;但对同属作物洋葱和大葱的发芽率、胚芽长和鲜重、胚根长和鲜重均表现为抑制作用。4.通过薄层层析分离的5个斑点中,斑点2、斑点3和斑点5对莴苣的萌芽有抑制作用,斑点1和斑点4有促进作用。分别通过GC-MS鉴定:斑点1主要有9-十八碳烯酸甲酯、双丙酮醇、己内酰胺、N,N-二丁基甲酰;斑点2中以2,2’-亚甲基双-(4-甲基-6-叔丁基苯酚)和邻苯二甲酸二乙酯等芳香族化合物为主;斑点3主要以1,8-二氨基环十四烷基-2,9-二酮、联苯和1-甲基萘等为主;斑点4中的化学物质以酯类物质为主,比如8-十八碳烯酸甲酯,棕榈酸甲酯和7,10 -十八碳二烯酸甲基酯;斑点5以芳香族化合物和脂肪族酯类化合物为主。5.施加EM(Effective Microorganisms)菌剂有利于改善连作大蒜根际土壤微生物结构,促进有益微生物正常活动和繁殖,抑制有害病菌的生长和繁殖;提高大蒜根际土壤酶的活性,降低有害物质的累积,提高土壤肥力;促进干物质量的积累来提高大蒜产量;调节作物的生理代谢功能,提高作物产量和改善作物的品质。更多还原

【Abstract】 With rapid population growth and socio-economic development, a raise in demand for some specific crop has brought modern agriculture characteristic with single-crop large-scale cultivation. As a widespread agriculture phenomenon, continuous cropping has caused great harm to agriculture and sideline many countries. Garlic is not only internationall loved health vegetables, but also an important seasoning and pharmaceutical raw materials. In china, it is an important raw material and export vegetables. Along with the continuous development of the production, continuous cropping phenomenon in the main production areas of garlic is a growing problem.In this test, in order to investigate the mechanism of continuous cropping of garlic and provide the scientific basis for easing garlic cropping obstacles, we have studied continuously cropped garlic from three aspects. In this test, in order to investigate the mechanism of continuous cropping of garlic and provide the scientific basis for easing garlic cropping obstacles, we have studied continuously cropped garlic from three aspects: first, allelopathy of root exudates and straw aqueous extracts of garlic; second, influence of continuous cropping garlic on rhizosphere microbial environment, yield and quality; and last, EM help relieve cropping obstacles of garlic. The main research results were summarized as follows:1. In short-term (5 years and 10 years), the number of bacteria, actinomycetes and various physiological groups from garlic rhizosphere soil rose dramatically; fungi’increased slowly; and soil enzyme activity increased gradually; soil microenvironment obtained improved; Garlic yield and quality were increased significantly. But in long-term (15 years and 20 years), the number of bacteria, actinomycetes and various physiological groups from garlic rhizosphere soil decreased; soil enzyme activity reduced; but the number of fungi raised; soil microenvironment turned to deterioration; garlic yield and quality were decreased significantly, continuous cropping obstacles was obvious.2. Garlic root exudates obtained by tissue culture method inhibited the germination and growth of genus allium crop seed such as welsh onion, onions and leek, and inhibition increased with increasing concentration of garlic root exudates. The main substances of garlic root exudates were identified by GC-MS as follows: 2,2’-methylenebis[6-(1,1-dimethylethyl) -4-methyl]-Phenol, dioctyl phthalate, 5-octanoyl-pyrimidine-2,4,6(1H,3H,5H)-trione, eicosanoic acid, ferulic acid, 9-hexade- cenoic acid, tetradecanoic acid and diallyl disulphide.3. In this study, the high concentration of garlic straw aqueous extracts inhibited the germination (embryo and radicle) of tomato, pepper and cucumber, but the low concentrations displayed promoter action. All concentration designed in this experiment restrained the germination rates of tomato and pepper, but had no obvious effect on cucumber’germination rate; garlic straw aqueous extracts showed inhibition on the germination of onion and welsh onion.4. Five spots were observed on TLC plates under UV light, with Rf values of 0.12(spot 1)、0.43(spot 2)、0.64(spot 3)、0.74(spot 4) and 0.88(spot 5). Of these, only three spots suppressed lettuce emergence, with spot 2, spot 3 and spot 5, respectively; and spot 1 and spot 4 promoted lettuce emergence. Several compounds were detected in the five spots collected by TLC as shown. The first spot consisted of 9-octa- decenoic acid, methyl este, diacetone alcohol, caprolactam, N,N-dibutyl- formamide. The second spot contained diethyl phthalate and a derivative of phenol (2,2’-methylenebis[6-(1,1-dimethylethyl) -4-methyl]-Phenol). 1,8-diazacyclotetradecane-2, 9-dione, biphenyl and 1-methyl- naphthalene were detected in the third spot. Several esters were observed in the fourth spot, including 8-octadecenoic acid methyl ester, hexadecanoic acid methyl ester and 7,10-octadecadienoic acid methyl ester. In the fifth spot, aromatic compounds and aliphatic ester were identified.5. EM (Effective Microorganisms) helped improve structure of rhizosphere microbial of continuously cropped garlic, promote beneficial microbial activities and normal reproduction and inhibit harmful pathogens growth and reproduction. Compared with the control, EM enhanced enzyme activities in garlic rhizosphere soil, reduced the accumulation of harmful substances, improved soil fertility. regulation of physiological metabolic functions crops, improve crop yields and improve crop quality. And the physiological metabolism of garlic was regulated, yields and quality were improved by use of EM.更多还原