【摘要】：植物內(nèi)生細菌是重要的微生物資源,其中不少種群能夠產(chǎn)生植物生長素,具有解磷固氮等活性,對宿主植物生長有明顯的促生作用,能提高宿主植物的抗逆性和產(chǎn)量。植物內(nèi)生細菌因此在減少化學(xué)農(nóng)藥和肥料的使用量、提高作物抗逆性及產(chǎn)量上具有很大潛力。近年玉米內(nèi)生菌資源的調(diào)查及其在玉米病害防治中的應(yīng)用研究受到國內(nèi)外科技工作者的廣泛重視,成為玉米病害環(huán)境友好型防控技術(shù)研究的一大熱點。為開發(fā)有效防治玉米病害的內(nèi)生細菌,作者從河南省南陽市采集不同生長期健康玉米植株樣品,按常規(guī)方法進行表面消毒分離得到39株內(nèi)生細菌。以39株玉米內(nèi)生細菌為研究對象,以促進玉米生長為初選指標(biāo),利用室內(nèi)和室外盆栽實驗相結(jié)合的方法,分析內(nèi)生細菌的促生效果,篩選出對玉米幼苗具有明顯促生作用的內(nèi)生細菌,為大田玉米南方銹病生防工作的開展提供強有力的備選菌株。對促生效果明顯的5株內(nèi)生細菌(L-2、R-4、R-8、R-14、S-3)進行16S rDNA分子鑒定,均屬芽孢桿菌屬。再綜合盆栽試驗、固氮作用、溶磷作用等促生指標(biāo),篩選出一株對玉米生長具有明顯促生作用內(nèi)生細菌R-4,根據(jù)形態(tài)學(xué)、生理生化特征和16S rDNA序列對內(nèi)生細菌R-4做進一步鑒定,確定為蠟樣芽孢桿菌(Bacillus cereus),其最適生長溫度為30℃,最適生長pH為8。用玉米內(nèi)生細菌R-4分別處理3個玉米品種(先玉335、浚單20、銀糯1號)后,測試其大田防病增產(chǎn)效果。3個玉米品種用R-4懸浮液處理后對南方銹病的平均防治效果分別達32.4%,產(chǎn)量平均增加了30.1kg/666.7m2,具有較好的開發(fā)應(yīng)用前景。田間試驗結(jié)果表明,用具有促生作用的內(nèi)生細菌R-4浸泡玉米種子后,對玉米南方銹病的防治以及產(chǎn)量的增加均有一定的效果,可能與該菌株具有較高的溶磷和固氮活性,能促進植株健康生長,提高植物抗病性有關(guān)。
[Abstract]:Plant endophytic bacteria are important microbial resources, many of which can produce plant auxin, have the activities of phosphorus and nitrogen fixation, have obvious promoting effect on the growth of host plants, and can improve the resistance and yield of host plants. Therefore, endophytic bacteria have great potential in reducing the use of chemical pesticides and fertilizers, improving crop resistance and yield. In recent years, the investigation of maize endophytic bacteria resources and their application in maize disease prevention and control have been widely paid attention to by scientists and technicians at home and abroad, and have become a hot spot in the research of environment-friendly maize disease prevention and control technology. In order to develop effective endophytic bacteria for controlling maize diseases, 39 endophytic bacteria were isolated from healthy maize plants in Nanyang City, Henan Province by surface disinfection. Taking 39 strains of maize endophytic bacteria as the research object and promoting the growth of maize as the primary index, the effects of endogenous bacteria on the growth of maize were analyzed by the combination of indoor and outdoor potted experiments. Endophytic bacteria with obvious promoting effect on maize seedlings were screened, which provided a strong alternative strain for the development of biological control of maize southern rust in the field. Five strains of endophytic bacteria (L-2R -4N R-8 R-14 S-3) were identified by 16s rDNA molecular identification. All of them belong to Bacillus genus. Based on pot experiment, nitrogen fixation and phosphorus dissolving, an endophytic bacterium R-4 was selected, which had obvious promoting effect on maize growth. The endophytic bacteria R-4 was further identified according to morphological, physiological and biochemical characteristics and 16s rDNA sequence. The optimum growth temperature and pH of Bacillus cereus (Bacillus cereus), were 30 鈩，

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