本文關(guān)鍵詞：西瓜連作障礙緩解技術(shù)及其機理研究　出處：《西北農(nóng)林科技大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 西瓜 連作障礙 緩解技術(shù) 土壤特性 枯萎病 細菌多樣性 高通量測序

【摘要】：西瓜(Citrullus lanatus(Trunb.)Matsum and Nakai)在我國具有較高的經(jīng)濟效益,但是其連作障礙嚴重影響西瓜生產(chǎn)可持續(xù)發(fā)展。如何解決連作障礙問題已成為世界性難題。西瓜連作障礙的實質(zhì)是西瓜連續(xù)栽培引起土壤特性發(fā)生了變化。大量研究表明,輪作和增施有機肥以及高溫悶棚可以緩解西瓜連作障礙。但很少有人對緩解連作障礙中土壤發(fā)生變化的機理進行系統(tǒng)的研究。基于此,本試驗以大蒜為輪作作物,牛糞和作物秸稈為有機肥,進行田間試驗和室內(nèi)培養(yǎng)分析,研究其對西瓜生長和枯萎病菌的影響,從對土壤理化性狀、生物學(xué)性狀和細菌群落多樣性影響的角度,探討其在緩解西瓜連作障礙中的作用,為其在生產(chǎn)中的應(yīng)用提供理論依據(jù)。主要結(jié)果如下:1、進行連續(xù)三年的田間西瓜栽培試驗,通過輪作大蒜和增施牛糞的技術(shù),分別研究它們對西瓜生長和土壤特性的影響。結(jié)果表明:西瓜連作后,植株長勢明顯變?nèi)?而實施大蒜輪作和施牛糞都可促進西瓜植株生長,增加產(chǎn)量,緩解這種現(xiàn)象。至三年試驗結(jié)束時,輪作大蒜和施牛糞分別使產(chǎn)量增加了67%和112%,枯萎病發(fā)病率降低38%和50%,而兩者相結(jié)合可增產(chǎn)138%,枯萎病發(fā)病率降低57%,這說明二者相結(jié)合具有疊加效應(yīng)。進一步研究發(fā)現(xiàn),輪作大蒜和增施牛糞顯著增加了細菌和放線菌的數(shù)量,降低了真菌的數(shù)量,同時,增加了細菌和真菌群落比值;無論是輪作大蒜還是增施牛糞均顯著增加了土壤中各酶(蛋白酶、脲酶、過氧化氫酶、蔗糖酶、多酚氧化酶和堿性磷酸酶)的活性;降低了土壤中總酚的含量;促進了土壤養(yǎng)分(速效氮、速效磷、速效鉀和有機質(zhì))的釋放,提高了連作地土壤的肥力。因此,可能是輪作大蒜更有利于土壤中細菌數(shù)量的增加和真菌數(shù)量的減少,從而減輕枯萎病的發(fā)病率;而牛糞對增加土壤酶活性的貢獻率更大,有利于土壤整體質(zhì)量的改良,從而增加西瓜產(chǎn)量。2、在溫室夏季休閑期,采用短期淹水高溫悶棚的技術(shù),研究其對后茬西瓜生長和土壤特性的影響。結(jié)果表明:短期淹水高溫悶棚使西瓜植株的株高增加29%,枯萎病發(fā)病率減少48%,西瓜產(chǎn)量提高57%。這可能主要是由于短期淹水高溫悶棚極顯著降低了土壤的容重,減少了各養(yǎng)分含量在土壤中的積累,有效降低了土壤的含鹽量,土壤的總酚含量顯著下降,細菌和放線菌數(shù)量顯著增加,真菌數(shù)量顯著減少。對西瓜生長與土壤特性進行相關(guān)性分析表明,植株發(fā)病率與細菌數(shù)量呈顯著負相關(guān),與全酚含量呈顯著正相關(guān),而與真菌和放線菌數(shù)量不相關(guān);產(chǎn)量與鹽分含量呈負相關(guān),與細菌和放線菌的數(shù)量呈正相關(guān)。因此,可能短期淹水高溫悶棚對細菌菌落的影響在減輕植株發(fā)病率和增加產(chǎn)量方面的作用更大。3、利用植物的化感作用,采用將供體植物(大蒜、茼蒿、萬壽菊、芹菜、小麥、三葉草)的秸稈加入到西瓜連作土中的技術(shù),研究不同秸稈腐解物浸提液對西瓜幼苗生長、植株發(fā)病率以及對西瓜枯萎病菌的影響。結(jié)果表明:不同秸稈腐解物的浸提液增加了西瓜種子胚根主根的長度和側(cè)根的數(shù)量,提高了幼苗干重的根冠比,降低了西瓜幼苗枯萎病的病情指數(shù)。分析它們的化感效應(yīng)發(fā)現(xiàn),不同秸稈腐解物均促進了西瓜尖孢鐮刀菌菌絲的生長,而顯著降低了菌絲的生物量,不同程度的抑制孢子萌發(fā);對尖孢鐮刀菌菌液的酶活性(淀粉酶、蛋白酶、果膠酶、纖維素酶)的化感作用因作物種類而不同,但大蒜對這四種酶活性均表現(xiàn)為化感抑制作用。因此,不同秸稈腐解物對西瓜枯萎病菌可能不是直接的抑制作用,而是通過增加微生物的活性產(chǎn)生代謝物質(zhì),從而抑制病原菌的生長。4、研究和分析了不同秸稈腐解在提高西瓜植株抗病性的過程中對西瓜連作土壤特性的影響。結(jié)果表明:不同秸稈腐解物顯著增加了連作土的微生物總量,促進了細菌在微生物總量中所占的比例;各腐解物的土壤酶活性得到了不同程度的提高,以大蒜的蛋白酶、脫氫酶和堿性磷酸酶活性最高,小麥的脲酶活性最高,三葉草的土壤蔗糖酶活性最高。不同秸稈的腐解顯著增加了連作土各養(yǎng)分的釋放,速效氮和速效磷的含量隨著腐解時間的延長處于增加的趨勢,速效鉀的含量先升高后降低,而有機質(zhì)含量受腐解時間的影響不大。各腐解物土壤的含鹽量隨著養(yǎng)分的釋放也相應(yīng)增加。土壤pH值與參試作物種類有關(guān)。進一步的化感效應(yīng)分析表明,不同腐解物對細菌和放線菌含量為化感促進作用,大蒜和萬壽菊對真菌含量及pH值變化為化感抑制作用。總之,不同秸稈腐解物對西瓜枯萎病菌的作用,可能是土壤微生物群體作用的結(jié)果,當土壤中微生物群落結(jié)構(gòu)越豐富,多樣性越高時,對抗病原菌的能力越強。5、為進一步探討植物與微生物的互作關(guān)系,利用Illumia HiSeq高通量測序平臺對16S rDNA的V4區(qū)擴增子進行測序,研究不同秸稈腐解物對西瓜連作地土壤中細菌群落多樣性及豐度的影響。結(jié)果表明:在門水平上(相對豐度排名前10),不同秸稈腐解物對土壤中細菌的優(yōu)勢菌群產(chǎn)生影響,各處理的優(yōu)勢菌門為變形菌門、厚壁菌門和擬桿菌門,而對照(連作土)的優(yōu)勢菌群有酸桿菌門、芽單胞菌門、浮霉菌門、泉古菌門、放線菌門和綠彎菌門;進一步統(tǒng)計物種數(shù)量在各水平上的差異,以門水平為例,大蒜和萬壽菊比對照各多了10個門,茼蒿比對照多了8個門,芹菜比對照多了6個門,小麥和三葉草比對照分別少了7個和6個。因此,不同秸稈腐解物通過增加土壤中細菌群落的相對豐度和物種多樣性,提高有益菌群在土壤中的比例,降低有害菌群在土壤中的相對含量,從而對病原菌產(chǎn)生拮抗作用。
[Abstract]:Watermelon (Citrullus Lanatus (Trunb.) Matsum and Nakai) is high in China's economic benefits, but the impact of serious continuous cropping watermelon production sustainable development. How to solve the problems of continuous cropping obstacle has become a worldwide problem. The essence of watermelon continuous cropping obstacle is caused by continuous cultivation of watermelon soil properties changed. A large number of studies show that rotation and organic fertilizer and high temperature disinfection can alleviate the watermelon continuous cropping obstacle. But there are few people to study systematically the mechanism to reduce changes of continuous cropping obstacles in. Based on this, the test for crop rotation with garlic, cow dung and crop straw as organic fertilizer, field experiment and laboratory analysis, to study its effect on the growth and Fusarium Wilt of watermelon, from the soil physical and chemical properties, biological characteristics and bacterial community diversity influence angle, discusses the ease of watermelon continuous cropping obstacle In effect, provide a theoretical basis for its application in production. The main results are as follows: 1, the field of watermelon cultivation test in three consecutive years, through the rotation of garlic and fertilizing cow dung, respectively to study their effects on the growth of watermelon and soil properties. The results show that the West as urizura, plant growth significantly weak, while the implementation of garlic rotation and applying cow dung can promote watermelon plant growth, increase yield, to alleviate this phenomenon. The end of the three year test, rotation of garlic and applying cow dung respectively. The yield was increased by 67% and 112%, wilt disease incidence rate decreased by 38% and 50%, and the combination of the two can be increased by 138%, wilt the incidence rate decreased by 57%, indicating that the combination of the two has additive effect. Further studies showed that the number of rotation of garlic and fertilizing cow dung significantly increased the bacteria and actinomycetes, reduced the number of fungi, at the same time, increase the population of bacteria and fungi Fall ratio; whether it is still adding garlic rotation manure significantly increased the soil enzyme (protease, urease, catalase, invertase, polyphenol oxidase and alkaline phosphatase) activity; reduce the content of total phenol in soil; promote the soil nutrients (available nitrogen, available phosphorus, available potassium and organic matter) release, improve the continuous cropping soil fertility. Therefore, may be more conducive to reducing the number of garlic rotation increased the quantity of soil bacteria and fungi, thus reducing the incidence of Fusarium wilt; and cow manure on soil enzyme activities increased the contribution rate of greater improvement to the overall quality of the soil, thereby increasing the watermelon the yield of.2 in summer fallow period in greenhouse, the waterlogging high temperature disinfection technology, study the influence of post harvest growth of watermelon and soil properties. The results showed that waterlogging high temperature disinfection watermelon plant height increased by 29%, The incidence of Fusarium Wilt of watermelon yield increase of 57%. decreased by 48%, which may be mainly due to short-term flooding high temperature disinfection significantly decreased soil bulk density, reduce the accumulation of nutrient content in the soil and reduce soil salt content, total phenol content in soil decreased significantly, the number of bacteria and actinomycetes significantly increase the number of fungi decreased significantly. The growth of watermelon and soil characteristics of the correlation analysis showed that the plant was negatively related to the number and incidence of bacteria was positively correlated with the total phenol content, and put the number of Actinomyces and fungi and related; yield was negatively correlated with salt content, and the number of positive bacteria and actinomycetes bacteria related. Therefore, the possible short-term flooding high temperature disinfection effect on the bacterial colonies to reduce plant morbidity and increase the role of greater.3 effect by plants, the donor plants (garlic, Chrysanthemum, marigold, celery, wheat, clover) straw into watermelon continuous cropping soil in the technology of different straw extracts on the growth of watermelon seedlings, plant incidence and effect on Watermelon Fusarium wilt. The results showed that different straw hydrolysate extract increased the number of watermelon seeds the radicle root length and lateral root, improve the seedling dry weight of root shoot ratio, reduce disease index of Fusarium Wilt of watermelon seedlings. Analyze their allelopathic effects that different straw decomposition increased Watermelon Fusarium oxysporum mycelia growth, and significantly reduced the biomass of mycelium, spores of different inhibition the degree of germination; enzyme activity of Fusarium oxysporum bacteria (amylase, protease, pectinase, cellulase) allelopathy for different crop species, but garlic on the activities of these four enzymes showed allelopathic effect. Therefore, The different straw hydrolysate on Fusarium oxysporum may not directly inhibit, but produce metabolites by increasing microbial activity, thereby inhibiting the growth of.4 pathogens, research and analysis of the effects of different straw soil characteristics on the West in the process of improving urizura resistance in watermelon plants. The results showed that different straw hydrolysate significantly increased the amount of soil microorganisms in continuous cropping, promote the bacteria in microbial accounted for the proportion of the total; soil enzyme activity in different composts were improved in different degrees, with garlic protease, alkaline phosphatase activity and dehydrogenase activity of urease was highest, the highest wheat, soil invertase activity was the highest in three grass. Different straw Composts significantly increased soil nutrient release, available nitrogen and available phosphorus content with the decomposition time in increasing trend, available The potassium content increased first and then decreased, while the content of organic matter is not affected by the decay time. The quantity of salt decomposition with soil nutrient release also increased. The pH value of soil and crop species tested. Further analysis showed that the allelopathic effect, different composts on bacteria and actinomycetes the content of bacteria for allelopathy effect, garlic and marigold on fungi content and pH value change in the sense of inhibition. In short, different straw composts on Watermelon Fusarium wilt effect may be soil microbial groups result, when more abundant in soil microbial community structure, diversity is higher, the ability against pathogens the stronger the bacteria.5, to further explore the interaction between plants and microorganisms, using Illumia HiSeq sequencing platform V4 of 16S rDNA amplicons were sequenced to study the effects of different straw composts on bacterial watermelon continuous cropping soil 緹よ惤澶氭牱鎬у強涓板害鐨勫獎鍝，

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