连作对黄芪品质形成和根际土壤微生物的影响及黄芪轮作换茬方式的研究

发布时间：2018-06-01 21:30

本文选题：蒙古黄芪 + 根际微生物　；参考：《内蒙古大学》2017年硕士论文

【摘要】：连作扰乱了根际土壤中对植物有益的微生物和病原微生物之间的平衡,对土壤健康和植物健康产生直接和间接的不利影响。研究连作障碍机制和寻找合理的轮作方式对解决连作障碍具有重要的意义。本研究以蒙古黄芪为实验材料,基于扩增子测序技术探究了连作1、3、6年黄芪根际土壤与非根际土壤的微生物群落组成结构及其多样性变化,探讨了各连作处理根际微生物数量和土壤酶活性的动态变化规律,分析了连作障碍对黄芪根腐病发病情况及生长发育、品质形成的影响,并对能够起到缓解黄芪连作障碍作用的合理轮作方式进行了初步研究。研究结果表明:1.在黄芪生长末期,连作年限的增加导致对植物生长有益的土壤红杆菌目减少,与根瘤形成相关的根瘤菌目、伯克氏菌目和黄色单胞菌目、粘球菌目连续增加,与病害相关的假单胞杆菌属、溶杆菌属丰度较大;且在黄芪病害高发期,连作6年黄芪根际土壤中致病菌丰度较大。连作后,黄芪根际土壤有益菌和致病菌的平衡关系被打破,根际土壤微生态失衡。2.连作黄芪根际土壤的细菌、真菌的群落结构和优势菌群均受到连作年限、取样时期和根际-非根际土的影响,细菌所受影响更明显。连作后黄芪根际土壤菌、真菌多样性降低,真菌多样性和丰富度在黄芪生长期内降低,连作6年的黄芪根际土壤细菌丰富度在生长期内降低。连作年限越多,对黄芪维持根际土壤微生物多样性越不利。3.连作年限的增加导致黄芪根际土壤细菌数量增加,真菌数量减少;脲和蔗糖酶活性降低,纤维素酶活性增加。在黄芪生长期内,细菌和放线菌数量增加,真菌数量减少,脲酶活性增加,蔗糖酶活性先增后减,纤维素酶活性波动变化。连作改变黄芪根际土壤微生物的组成、数量及酶活性对其根际土壤健康产生不利影响。4.连作黄芪具有较高的根腐病发病率,且连作后黄芪生长速度减缓,生牧量降低;连作6年不利于黄芪毛蕊异黄酮葡萄糖苷、毛蕊异黄酮和芒柄花素的积累。可见连作增加黄芪根腐病的发病率,抑制黄芪生长,导致品质变劣。5.以马铃薯、莜麦、油菜换茬的轮作处理中,黄芪-莜麦-黄芪轮作能够提高黄芪根际土壤酸性磷酸酶和脲酶活性,降低根腐病重度发病率,促使黄芪根冠比增加,提高毛蕊异黄酮葡萄糖苷和芒柄花苷的含量。即以莜麦换茬有利于改善土壤和黄芪正常生长发育,是比较适用于消减黄芪连作障碍的轮作方式。
[Abstract]:Continuous cropping disturbed the balance between plant beneficial microorganisms and pathogenic microorganisms in rhizosphere soil and had direct and indirect adverse effects on soil health and plant health. It is of great significance to study the mechanism of continuous cropping obstacle and to find a reasonable rotation way to solve the obstacle of continuous cropping. In this study, the composition and diversity of microbial communities in rhizosphere soil and non-rhizosphere soil of Astragalus mongolicus were studied based on Amplifier sequencing technique. The dynamic changes of microorganism quantity and soil enzyme activity in rhizosphere of different continuous cropping treatments were discussed, and the effects of continuous cropping disturbance on the occurrence, growth and development of root rot of Astragalus membranaceus and the formation of quality were analyzed. A preliminary study was carried out on the reasonable rotation mode which could alleviate the obstacle of continuous cropping of Astragalus membranaceus (Astragalus membranaceus). The results of the study show that 1: 1. At the end of the growth of Astragalus membranaceus, the increase of continuous cropping years led to the decrease of the order Erythrobacter which was beneficial to plant growth, the increase of rhizobia related to rhizobia formation, the order of Burkellidsp. and xanthomonas, and the increase of myxococci. Pseudomonas associated with disease, lysobacillus was abundant, and the pathogen abundance in rhizosphere soil of Astragalus membranaceus was higher than that of Astragalus membranaceus in the period of high incidence of disease of Astragalus membranaceus in the rhizosphere of Astragalus membranaceus. After continuous cropping, the balance between beneficial bacteria and pathogenic bacteria in rhizosphere soil of Astragalus membranaceus was broken, and the microecological imbalance of rhizosphere soil was 0.2. In the rhizosphere soil of Astragalus membranaceus, the community structure and dominant flora of fungi were affected by the years of continuous cropping, the sampling period and the rhizosphere-non-rhizosphere soil, and the effect of bacteria was more obvious. In the rhizosphere soil of Astragalus membranaceus after continuous cropping, the fungal diversity decreased, the fungal diversity and richness decreased during the growth period of Astragalus membranaceus, and the bacterial richness in rhizosphere soil of Astragalus membranaceus after 6 years of continuous cropping decreased during the growing period. The more years of continuous cropping, the more disadvantageous to maintain rhizosphere soil microbial diversity of Astragalus membranaceus. The number of bacteria in rhizosphere of Astragalus membranaceus increased and the number of fungi decreased, the activities of urea and sucrase decreased, and the activity of cellulase increased with the increase of continuous cropping years. During the growth period of Astragalus membranaceus, the number of bacteria and actinomycetes increased, the number of fungi decreased, the activity of urease increased, the activity of sucrase first increased and then decreased, and the activity of cellulase fluctuated. Continuous cropping changed the composition, quantity and enzyme activity of rhizosphere microorganism of Astragalus membranaceus. Continuous cropping of Astragalus membranaceus had a higher incidence of root rot, and after continuous cropping, the growth rate of Astragalus membranaceus slowed down, and the amount of raw animal husbandry decreased, while 6 years of continuous cropping was not conducive to the accumulation of isoflavone glucoside, isoflavone and Acanthopanthin in Astragalus membranaceus. It can be seen that continuous cropping increases the incidence of root rot of Astragalus membranaceus, inhibits the growth of Astragalus membranaceus, and results in the deterioration of quality. In the rotation of potato, naked oats and rapeseed, the activities of acid phosphatase and urease in rhizosphere soil of Astragalus membranaceus were increased, and the serious incidence of root rot was decreased, and the ratio of root to shoot increased. The contents of isoflavone glucoside and anthocyanin were increased. The change of stubble of naked oats is beneficial to improve the soil and the normal growth and development of Astragalus membranaceus, which is more suitable for reducing the obstacle of continuous cropping of Astragalus membranaceus.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S154.3;S567.239

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