低磷胁迫对番茄根系生长及根际土壤微生物多样性的影响

发布时间：2018-10-05 18:49

【摘要】：番茄(Tomato)是我国大规模种植的蔬菜之一。随着番茄种植面积和种植年限的增加,番茄生产过程中存在的缺素、连作障碍问题越来越明显。例如：番茄生长过程中缺磷会导致生长缓慢,开花结果期延迟等缺素症状。本试验以低磷胁迫和平衡施肥处理的番茄根系及根际土壤为研究对象,采用WinRHIZO根系分析系统、稀释平板法、PCR-DGGE等现代和传统分析技术,研究低磷胁迫对番茄根系生长,以及根际土壤理化性状、生物学特性和微生物群落结构的影响。研究结果如下：(1)低磷胁迫导致番茄根系总根长、总根表面积、总根体积和根尖数等生长指标显著下降,且低磷胁迫对不同番茄品种根系生长影响程度不一致；低磷胁迫条件下,番茄地上部分的生长受限,根冠比显著增大。(2)低磷胁迫条件下,番茄根际土壤全磷、速效磷、全钾含量和pH显著低于平衡施肥处理。(3)低磷胁迫导致根际土壤中可培养微生物(细菌、真菌和放线菌)数量、土壤酶(p-葡糖苷酶、氨肽酶和磷酸二酯酶)活性、微生物生物量(C、N和P)不同程度地降低。(4)低磷胁迫条件下,番茄根系形态指标与根际土壤理化性状、生物学性状均存在相关性。其中,番茄根系形态指标与土壤全磷、速效磷、速效钾含量达到显著或极显著相关,与土壤p-葡糖苷酶、微生物生物量碳也达到显著或极显著相关。(5)低磷胁迫处理显著改变了土壤细菌群落结构,导致部分诸如甲基杆菌属(Methylobacterium sp.)等具有解磷功能的菌群缺失。同时,低磷胁迫导致番茄根际土壤细菌多样性指数(H)、丰富度(S)和均匀度指数(Eh)降低。并测序结果表明：低磷胁迫条件下,番茄根际土壤中的细菌种群主要为不可培养细菌种属,但亦出现鞘脂单胞属(Sphingopyxis sp.)、甲基杆菌属(Methylobacterium sp.)、金黄杆菌属(Chryseobacterium sp.)以及大肠杆菌属(Escherichia coli sp.)等部分具有解磷功能的可培养细菌种属。(6)低磷胁迫处理对番茄根际土壤真菌群落结构的影响与细菌相似。低磷胁迫亦导致番茄根际土壤真菌多样性指数(H)、丰富度(S)和均匀度指数(Eh)下降。测序结果同样表明：低磷胁迫条件下,番茄根际土壤中优势真菌种属亦以不可培养真菌为主,同时亦包含部分具有解磷功能的青霉属(Penicillium sp.)、镰刀菌属(Fusarium sp.)、曲霉属(Aspergillus sp.)等可培养真菌种属。综上所述,低磷胁迫条件下,番茄根际土壤微生物群落结构劣化和肥力下降是导致番茄植株生长不良的根本原因。平衡施肥对番茄的正常生长和提升土壤肥力以及维护土壤健康具有极其重要的作用。
[Abstract]:Tomato (Tomato) is one of the vegetables grown on a large scale in China. With the increase of tomato planting area and planting years, the problem of deficiency and continuous cropping obstacle in tomato production is becoming more and more obvious. For example, lack of phosphorus in tomato growth can lead to slow growth, delayed flowering and other vegetative symptoms. In this experiment, the root system and rhizosphere soil of tomato under low phosphorus stress and balanced fertilization were used to study the effects of low phosphorus stress on tomato root growth by using WinRHIZO root analysis system, dilution plate PCR-DGGE and other modern and traditional analytical techniques. And the effects of physical and chemical properties, biological characteristics and microbial community structure of rhizosphere soil. The results were as follows: (1) the total root length, total root surface area, total root volume and root tip number of tomato roots were significantly decreased under low phosphorus stress, and the effects of low phosphorus stress on root growth of different tomato varieties were not consistent; Under low phosphorus stress, the growth of aboveground part of tomato was restricted, and the ratio of root to shoot increased significantly. (2) under low phosphorus stress, total phosphorus and available phosphorus in tomato rhizosphere soil were increased. Total potassium content and pH were significantly lower than those of balanced fertilization. (3) low phosphorus stress resulted in the number of culturable microorganisms (bacteria, fungi and actinomycetes) and the activities of soil enzymes (pglucosidase, aminopeptidase and phosphodiesterase) in rhizosphere soil. Microbial biomass (Con N and P) decreased in varying degrees. (4) under low phosphorus stress, the root morphological indexes of tomato were correlated with physicochemical and biological characters of rhizosphere soil. Among them, the root morphological index of tomato was significantly correlated with soil total phosphorus and available potassium content, and with soil pglucosidase. Microbial biomass carbon was also significant or extremely significant. (5) low phosphorus stress significantly changed the soil bacterial community structure, resulting in some such as methyl bacillus (Methylobacterium sp.) And so on. At the same time, low phosphorus stress resulted in the decrease of bacterial diversity index (H),) richness (S) and evenness index (Eh) in tomato rhizosphere soil. The results of sequencing showed that under low phosphorus stress, the bacterial population in tomato rhizosphere soil was mainly unculturable, but there were also sphingomonas, (Sphingopyxis sp.), methyl bacillus, (Methylobacterium sp.), goldsp. (Chryseobacterium sp.). And Escherichia coli (Escherichia coli sp.) (6) the effect of low phosphorus stress on the fungal community structure of tomato rhizosphere soil was similar to that of bacteria. Low phosphorus stress also decreased the (H), richness (S) and evenness index (Eh) of tomato rhizosphere soil fungi diversity index. The results of sequencing also showed that under low phosphorus stress, the dominant fungi species in tomato rhizosphere soil were mainly non-cultured fungi, and also included some of the phosphate-releasing function of Penicillium (Penicillium sp.), (Fusarium sp.), Aspergillus (Aspergillus sp.). Species of culturable fungi. In conclusion, under low phosphorus stress, the deterioration of soil microbial community structure and the decrease of fertility in tomato rhizosphere were the root causes of the poor growth of tomato plants. Balanced fertilization plays an important role in tomato growth, soil fertility and soil health.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S641.2;S154.3

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