轮作模式下马铃薯土壤微生物多样性、酶活性及根系分泌物的研究

发布时间：2018-05-03 11:54

本文选题：轮作模式 + 微生物多样性　；参考：《甘肃农业大学》2016年博士论文

【摘要】：连作障碍的形成因素十分复杂,不仅涉及植物本身的自毒作用,而且受根际环境中微生物、土壤理化特性、养分异化等各项因素及其互相的影响而导致连作减产。轮作是维持土壤生境平衡的有效途径,但对不同作物轮作调控土壤微生态系统,修复和遏制连作退化土壤的机理和技术的研究相对欠缺,使得种植制度在提高土壤生态系统稳定性方面的潜力未能充分挖掘和利用。本研究在长期定位试验的基础上,采用传统的土壤学和微生物学方法与454测序技术相结合,研究了休闲、不同前茬轮作和连作条件下马铃薯土壤微生物群落结构、细菌和真菌多样性变化以及土壤酶活性,并进一步利用GC-MS技术,以连作为对照,分析了轮作对马铃薯根系分泌物的组成及累积效应的影响。主要结论如下:(1)与马铃薯连作相比,小麦-马铃薯轮作以及豌豆-马铃薯轮作马铃薯产量和水分利用效率均显著提高。2013年和2015年,小麦和马铃薯轮作以及豌豆和马铃薯轮作马铃薯产量较连作分别提高了23.49%、25.46%和29.08%、26.73%;水分利用效率提高了15.21%、13.24%和15.30%、10.90%。2014年小麦-豌豆-马铃薯轮作马铃薯产量和水分利用效率较马铃薯连作处理分别增加了31.42%和18.74%。(2)轮作土壤细菌Chao1指数、ACE指数、Shannon指数和np Shannon指数显著高于连作土壤。马铃薯轮作后变形菌门α-变形菌纲、β-变形菌纲、γ-变形菌纲和δ-变形菌纲数量减少。豌豆-马铃薯轮作土壤Sphingomonas(鞘氨醇单胞菌属)数量显著高于小麦-马铃薯以及小麦-马铃薯-马铃薯轮作土壤。(3)不同轮作模式对土壤真菌种群结构产生了明显的影响,优势种群在轮作、休闲和连作土壤中的地位发生了变化。与连作相比,轮作和休闲土壤Chao1指数和ACE指数减少,且差异达显著水平(P0.05)。轮作土壤中Basidiomycota(担子菌门)丰富度高于连作土壤。Eurotiomycetes(散囊菌纲)、Pezizomycetes(盘菌纲)和Agaricomycetes(伞菌纲)种类大小均明显高于连作土壤。各供试土壤中均出现了一些有害病原菌,如Phoma(茎点属)、Penicillium(青霉属)、Myrothecium(漆斑属),Fusarium(镰孢属)、Verticillium(轮枝孢属)等。Phom、Myrothecium和Verticillium在轮作和休闲土壤中数量显著减少。各供试土壤中均出现了一些有益真菌,Aspergillus(曲霉属)和Chaetomium(毛壳属)在轮作和休闲土壤中数量明显增加。(4)土壤微生物三大种类的数量大小为:细菌放线菌真菌。土壤细菌数量占微生物总量的43~90%。由于试验区的土壤呈弱碱性,放线菌所占比重较大,占微生物总量的6~57%。真菌数量最少,仅占微生物总量的0.2~5.6%。轮作土壤微生物总量和细菌数量显著增加,真菌数量的增长受到抑制。马铃薯全生育期土壤细菌变化趋势为:W-P-W-P(小麦-马铃薯-小麦-马铃薯)G-P-G-P(豌豆-马铃薯-豌豆-马铃薯)P-P-P-P(马铃薯连作)CK(休闲)。表明轮作促使土壤微生物大量繁殖,小麦和马铃薯轮作有利于增加土壤细菌数量。G-P-G-P比W-P-W-P处理真菌数量分别增加了58.33%、39.02%和68.18%。说明豌豆和马铃薯轮作有利于提高土壤中真菌的数量。(5)轮作种植改变了土壤酶活性。轮作土壤马铃薯全生育期蔗糖酶和脲酶活性高于连作土壤,且差异达显著水平(P0.05);与马铃薯连作2年相比,轮作土壤过氧化氢酶活性减弱,与连作3年和4年相比,轮作土壤过氧化氢酶活性增强;与连作2年相比,轮作土壤多酚氧化酶活性提高,与连作3年相比,轮作土壤多酚氧化酶活性呈现“高--低--高-低”变化趋势,与连作4年相比,轮作土壤多酚氧化酶活性降低。土壤过氧化氢酶活性与蔗糖酶、脲酶、真菌数量呈显著负相关关系,微生物总量与真菌数量呈显著正相关关系。说明作物轮作后改善了土壤微生态环境,激发了土壤碳氮相关酶的代谢活性,减缓了根际周围过氧化氢对作物的毒害,对连作退化土壤质量有着积极的改善作用。(6)不同种植模式马铃薯根系分泌物中有17种化合物均被鉴定出,主要包括烷烃类、酯类、胺类、酸类和生物碱化合物,且烃类、酯类、酸类相对含量较高,平均为22.13%、6.7%和6.08%。轮作处理马铃薯根系分泌物种类比固定间作和连作处理分别减少了12.12%和14.71%,烷烃类物质的相对含量比固定间作和连作处理分别减少了36.78%和34.47%,酸类物质的相对含量比固定间作和连作处理分别减少了39.55%和12.89%。连作处理马铃薯根系分泌物中鉴定出乙胺、N-乙基吗啉和邻苯二甲酸二丁酯的相对含量分别为1.46%、2.87%和5%,而在轮作和间作处理中均未检测到。轮作处理鉴定出N,N-二乙基乙酰胺相对含量比间作和连作处理分别减少55.22%和32.41%,棕榈酸相对含量比固定间作和连作处理分别减少了28.57%和18.82%,硬脂酸相对含量比固定间作和连作处理分别减少了28.47%和21.48%。说明大豆-马铃薯轮作可有效降低马铃薯根系分泌物组分的种类和含量。马铃薯根系分泌物中3种主要成分棕榈酸、硬脂酸、邻苯二甲酸二丁酯单独作用于马铃薯时,均显著抑制了马铃薯的生长,表现为化感负效应。
[Abstract]:The formation factors of continuous cropping obstacles are very complex, which not only involves the self toxicity of plants themselves, but also causes reduction in continuous cropping by microorganisms, soil physical and chemical properties, nutrient dissimilation and other factors in the rhizosphere environment. Rotation is an effective way to maintain soil habitat balance, but the soil microecology is regulated by different crop rotation. The mechanism and technology of restoration and containment of continuous cropping soil are relatively deficient, and the potential of the planting system in improving the stability of soil ecosystem has not been fully exploited and utilized. Based on the long-term localization test, this study combines the traditional soil and microbiological methods with the 454 sequencing technology. The microbial community structure, the diversity of bacteria and fungi and the activity of soil enzyme under the condition of different crop rotation and continuous cropping, and further using GC-MS technology to analyze the effects of rotation on the composition and cumulative effect of potato root exudates. The main conclusions are as follows: (1) connect with potatoes. In comparison, the yield and water use efficiency of potato and potato rotation and pea potato rotation increased significantly in.2013 and 2015. The yield of wheat and potato rotation and potato and potato rotation increased by 23.49%, 25.46% and 29.08%, 26.73% respectively, and the water use efficiency increased by 15.21%, 13.24% and 15., respectively. 30%, in 10.90%.2014, the yield and water use efficiency of wheat and pea potato rotation increased by 31.42% and 18.74%. (2), respectively, and the Chao1 index of soil bacteria, ACE index, Shannon index and NP Shannon index were significantly higher than that of continuous cropping soil. The number of gamma deforminus and delta deforminus decreased. The number of Sphingomonas (Sphingomonas Sphingomonas) soil in pea potato rotation soil was significantly higher than that of wheat potato potato and potato potato potato rotation soil. (3) different cropping patterns have significant effects on soil fungal population structure, dominant population in rotation, leisure and continuous cropping. The status of soil was changed. Compared with continuous cropping, the Chao1 index and ACE index of rotation and leisure soil decreased, and the difference reached significant level (P0.05). The abundance of Basidiomycota (basidiomycetes) in soil was higher than that of continuous cropping soil.Eurotiomycetes (Sclerotinia), Pezizomycetes (clonomycetes) and Agaricomycetes (agaromycetes). It was significantly higher than continuous cropping soil. Some harmful pathogens were found in all the tested soils, such as Phoma (stem point), Penicillium (Penicillium), Myrothecium (lacquer), Fusarium (Fusarium), Verticillium (cladospora),.Phom, Myrothecium and Verticillium in the rotation and leisure soil. Some beneficial fungi, the number of Aspergillus (Qu Meishu) and Chaetomium (Mao Keshu) in the rotation and the leisure soil increased significantly. (4) the number of three species of soil microbes was: bacterial actinomycete fungi. The amount of soil bacteria accounted for 43~90%. of the total microbial biomass because the soil in the experimental area was weak alkaline, and the proportion of actinomycetes accounted for a large proportion. The total amount of 6~57%. fungi was the least. The total amount of soil microbes and the number of bacteria increased significantly in the 0.2~5.6%. rotation of the total microbial biomass, and the increase of the number of fungi was inhibited. The change trend of soil bacteria in the whole growth period of potato was W-P-W-P (wheat potato wheat potato) G-P-G-P (PEA potato pea potato) P -P-P-P (potato continuous cropping) CK (leisure). Indicates that the rotation of soil microbes to promote the mass reproduction of soil microorganisms, wheat and potato rotation is beneficial to increase the number of soil bacteria increased by 58.33% than the number of W-P-W-P treated fungi respectively, 39.02% and 68.18%. show that pea and potato rotation is beneficial to increase the number of fungi in the soil. (5) rotation planting change The activity of soil enzyme was changed. The activity of invertase and urease in the whole growth period of potato was higher than that of continuous cropping soil, and the difference reached significant level (P0.05). Compared with the continuous cropping of potato for 2 years, the activity of catalase in soil was weakened. Compared with continuous cropping for 3 years and 4 years, the activity of hydrogen peroxide enzyme in soil was enhanced. Compared with continuous cropping for 2 years, the soil was rotten soil. The activity of polyphenol oxidase in soil was higher than that of continuous cropping for 3 years. The activity of polyphenol oxidase in soil was "high low to low", and the activity of polyphenol oxidase in soil was lower than that of continuous cropping for 4 years. The activity of soil catalase was significantly negatively correlated with the amount of invertase, urease and fungi, and the amount of microorganism and the amount of fungi. It showed that crop rotation improved soil microecological environment, stimulated the metabolic activity of soil carbon and nitrogen related enzymes, slowed down the toxicity of hydrogen peroxide around the rhizosphere, and had a positive improvement on the quality of continuous cropping soil. (6) there were 17 compounds in potato root exudates in different planting patterns. They were identified as alkanes, esters, amines, acids and alkaloids, and the relative content of hydrocarbons, esters and acids was higher, averaging 22.13%, 6.7% and 6.08%. in the potato root exudates were reduced by 12.12% and 14.71% compared with fixed intercropping and continuous cropping, and the relative content of alkanes was compared with the fixed Intercropping. The relative content of continuous cropping was reduced by 36.78% and 34.47% respectively. The relative content of acid material decreased by 39.55% and 12.89%. continuous cropping treatment respectively, and the relative content of N- ethyl morpholine and dibutyl phthalate was 1.46%, 2.87% and 5% respectively in potato root exudates, respectively, in rotation and intercropping treatment. The relative content of N N- two ethyl acetamide decreased by 55.22% and 32.41% respectively, and the relative content of palmitic acid decreased by 28.57% and 18.82% respectively compared with the fixed intercropping and continuous cropping treatment, and the relative content of stearic acid decreased by 28.47% and 21.48%. respectively compared with the fixed intercropping and intercropping treatment, respectively. Potato rotation can effectively reduce the variety and content of root exudates in potato. The growth of potato is inhibited significantly when the 3 main components of potato root exudates, palmitic acid, stearic acid, and dibutyl phthalate alone in potato, show a negative effect of allelopathy.

【学位授予单位】：甘肃农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S532;S154

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