设施果树栽培应注意的几个问题

日光温室和塑料大棚等设施果树栽培是高效农业的范畴,这种生产方式投资大,收益好,风险性也高.为了尽可能地避免造成损失,在进行设施果树栽培时应慎重对待以下问题:     

菌核生枝顶孢霉次生代谢物对桃褐斑致病菌的抑制效果

菌核生枝顶孢霉(Acremoniumsclerotigenum)作为枝顶孢属真菌的优势种,其次生代谢产物多样。为了明确其对植物病害致病菌的抑制效果,以桃褐斑致病菌(Alternariaalternata)为靶标菌,采用菌丝生长速率法和孢子萌发法测定6种发酵液的抑菌活性。结果表明:PD培养基发酵液提取物对桃褐斑致病菌的抑制效果最好,对菌丝生长和孢子萌发的EC50分别为53.6734mg/L和808.1584mg/L;培养5d的PD培养基发酵液的抑菌效果最好,对菌丝生长和孢子萌发的EC50分别为1.4458mg/L和309.6318mg/L;菌核生枝顶孢霉发酵液对桃褐斑致病菌菌丝生长的抑制效果优于对孢子萌发效果。该研究结果为将其开发成生物源农药奠定了理论基础。     

一株新的引起玉米细菌性茎腐病病原细菌的分离鉴定

In 2019, the disease was observed in the maize growing areas of Dehong County, Yunnan Province, China. On the basis of signs and symptoms, the disease was characterized as a bacterial infection. Identification of the pathogen were based on morphological characteristics, biology and physiological and biochemical assay, 16S rDNA and specific rpoD and gapA gene sequence analysis. The results show that the pathogen is similar to short rod in shape under a transmission electron microscope, the both ends are obtuse and have 1-3 terminal flagella. In King’s B medium, it produced milky white, round, smooth surface and transparent edge colonies and can utilize the 58 kinds of carbon sources. The LOPAT test result is “+++-+”. The construction of evolutionary trees was based on the 16S rDNA、rpoD and gapA gene sequencing, which indicated the closest genetic relationship with Pseudomonas extremorientalis and which was finally identified as P. extremorientalis. To our acknow-ledgment, this is the first report on the bacterial stalk rot disease of maize caused by phytopathogenic bacteria P. extremorientalis.     

抗生素溶杆菌13-6对玉米小斑病的生防作用机制初步研究

 玉米小斑病是玉米生产中的重要病害之一,本研究利用传统植物病理学和荧光定量PCR方法,研究抗生素溶杆菌对玉米小斑病菌(Bipolaris maydis)的生防效果和作用机制,为玉米小斑病的生物防控提供理论依据。结果显示,抗生素溶杆菌13-6对玉米小斑病菌丝生长和孢子萌发具有显著抑制作用,造成菌丝顶端生长受阻、表面粗糙,部分菌丝破裂,代谢粗提物抑制孢子萌发率高达92.19%,PI荧光染色显示病原菌孢子破裂并死亡。温室叶面喷施13-6发酵液、发酵液粗提物后显著降低玉米小斑病病情指数,相对防效分别达到42.43%和68.06%。诱导抗性实验表明:13-6对玉米小斑病的诱导防效达49.57%。玉米植株体内相关抗性基因表达结果显示,在灌根处理3 d后,抗病相关基因PR1和PR5、脂氧合酶LOX、乙烯受体ETR1均被激活表达,9 d达到最大值。研究证实抗生素溶杆菌13-6对玉米小斑病具有较好的生防效果,直接喷施可减缓玉米小斑病的发生,灌根施用使植株产生诱导抗性。