本文選題：土壤團(tuán)聚體　切入點(diǎn)：產(chǎn)胞外多糖細(xì)菌篩選　出處：《南京農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：土壤團(tuán)聚體是土壤結(jié)構(gòu)的基本單位,是土壤肥力的基礎(chǔ)。土壤團(tuán)聚體結(jié)構(gòu)的形成和穩(wěn)定主要是通過(guò)土壤中各種膠結(jié)物質(zhì)的膠結(jié)作用實(shí)現(xiàn)的。微生物及其胞外多聚物對(duì)土壤團(tuán)聚體的形成具有重要的作用。另外,土壤水穩(wěn)性團(tuán)聚體的形成,必須依賴于土壤中的有機(jī)物質(zhì)。良好的團(tuán)聚體結(jié)構(gòu)對(duì)農(nóng)業(yè)的可持續(xù)發(fā)展有著十分重要的意義。本文對(duì)產(chǎn)胞外多糖細(xì)菌、真菌以及有機(jī)肥在改善土壤團(tuán)聚體結(jié)構(gòu)中的作用進(jìn)行了研究,研究結(jié)果分述如下:1.從土壤中分離篩選出兩株產(chǎn)胞外多糖較多的菌株21和菌株G1。通過(guò)形態(tài)觀察、生理生化實(shí)驗(yàn)、16SrRNA基因同源性分析,初步鑒定菌株21為微桿菌,菌株G1為巨大芽孢桿菌。菌株21在培養(yǎng)溫度為30℃,裝液量為50 mL/250 mL,初始pH為7.0,碳源為蔗糖時(shí)可達(dá)到最大的生長(zhǎng)量;菌株G1在培養(yǎng)溫度為30℃,裝液量為75 mL/250 mL,初始pH為7.0,碳源為蔗糖、葡萄糖或淀粉,氮源為酵母粉、蛋白胨或牛肉膏時(shí)可達(dá)到最大的生長(zhǎng)量。2.采用土培試驗(yàn)研究了接種微生物(產(chǎn)胞外多糖細(xì)菌菌株21、G1或木霉T037)、施用有機(jī)肥(干豬糞和中藥渣堆肥)對(duì)土壤團(tuán)聚體的影響,結(jié)果發(fā)現(xiàn),接種產(chǎn)胞外多糖細(xì)菌菌株21、菌株G1或木霉T037,再結(jié)合使用干豬糞和中藥渣堆肥,均能增加土壤中大團(tuán)聚體的數(shù)量,其中施加干豬糞比施加中藥渣堆肥的效果更顯著;降低了0.25 mm水穩(wěn)性團(tuán)聚體的數(shù)量,降低的比例在2.79%～43.56%;提高了各粒徑團(tuán)聚體中微生物的豐富度,而且團(tuán)聚體的粒徑越大,微生物的豐度越高;在不同程度上改變了 土壤細(xì)菌的群落結(jié)構(gòu),改變了土壤中不同細(xì)菌門和細(xì)菌屬的相對(duì)豐度,增加了土壤細(xì)菌的豐富度和多樣性,但同一處理不同粒徑團(tuán)聚體中的細(xì)菌群落結(jié)構(gòu)相似性較高。分別施加干豬糞和中藥渣堆肥的處理均能增加土壤有機(jī)質(zhì)、總氮、速效磷和速效鉀的含量以及土壤脲酶和蔗糖酶的活性,且施加干豬糞的處理效果更加顯著;隨著團(tuán)聚體粒徑越小,土壤蔗糖酶和脲酶活性越低。接種產(chǎn)胞外多糖細(xì)菌并施加有機(jī)肥的處理和接種木霉T037并施加肥料的處理比單純施加有機(jī)肥的處理對(duì)提高大團(tuán)聚體含量的效果更顯著;接種產(chǎn)胞外多糖細(xì)菌菌株21、菌株G1的處理和接種木霉T037的處理,均可以提高各粒徑團(tuán)聚體中土壤多糖的含量,且從團(tuán)聚體粒徑2 mm到團(tuán)聚體粒徑0.25-1 mm,總體上呈現(xiàn)一個(gè)團(tuán)聚體粒徑越大,土壤多糖含量越高的趨勢(shì)。3.用施肥和接種產(chǎn)胞外多糖細(xì)菌菌株21、G1或木霉T037培育了一年的土壤種植番茄,結(jié)果發(fā)現(xiàn)經(jīng)過(guò)培育過(guò)的土壤能有效促進(jìn)番茄植株的生長(zhǎng),顯著地增加番茄植株的株高、莖粗、地上部干鮮重和地下部干、鮮重。另外,施加干豬糞培育的土壤還能提高番茄葉片的葉綠素含量。
[Abstract]:Soil aggregates are the basic units of soil structure, The formation and stabilization of soil aggregate structure is mainly through the cementation of various cementation substances in soil. Microorganisms and their extracellular polymers play an important role in the formation of soil aggregates. The formation of soil water stable aggregates must depend on the organic matter in the soil. Good aggregate structure is very important for the sustainable development of agriculture. The effects of fungi and organic fertilizer on improving the structure of soil aggregates were studied. The results were as follows: 1. Two strains 21 and G1 were isolated from the soil, which produced more extracellular polysaccharides. The homology analysis of 16s rRNA gene in physiological and biochemical experiments showed that strain 21 was microbacillus and strain G1 was Bacillus megaterium. Strain 21 was cultured at 30 鈩，

本文編號(hào)：1679071