关键词:

text-align:justify, text-indent:0cm, "> 多粘类芽孢杆菌, 颗粒剂研制, 黄瓜枯萎病, 防治效果

Abstract:

Endophytic Paenibacillus polymyxa hg18 exhibits favorable control efficacy against Fusarium oxysporum f. sp. cucumerinum causing cucumber Fusarium wilt. In this study, single-factor tests and orthogonal experiments were conducted to screen the composition and proportion of the granular formulation of strain hg18, and its quality indices, control efficacy, as well as its effects on chlorophyll content and defense-related enzyme activities in cucumber leaves were determined. The results showed that the optimal formulation of the granules was as follows: master powder 97% (diatomite and bacterial broth at a mass ratio of 1∶2), calcium carbonate 1%, polyethylene glycol 1%, sodium carboxymethyl cellulose 1%, mixed with 2% sodium alginate solution at a mass ratio of 1∶5, and then dropped into 0.2 mol/L calcium chloride solution for granulation. With this formulation, the viable count of the granules reached 6.62×10⁹ CFU/g, with a contamination rate of 3.41%, moisture content of 11.47%, fineness of 100%, pH of 6.20, and hardness of 100%, all meeting the national standards. Pot experiments demonstrated that when applied at 1.2% of the substrate mass, the granular formulation of strain hg18 achieved preventive and curative efficacies of 61.36% and 56.82%, respectively, against cucumber Fusarium wilt. Furthermore, the granular formulation significantly increased the contents of chlorophyll a, chlorophyll b, and total chlorophyll in cucumber leaves, and induced significant increases in the activities of defense-related enzymes such as SOD, POD, CAT and PAL, thereby enhancing systemic resistance in plants. This study lays a foundation for the development of P. polymyxa hg18 and provides a scientific foundation for the application of biocontrol agents against cucumber Fusarium wilt.

Key words:

text-align:justify, text-indent:-52.5pt, "> Paenibacillus polymyxa, granule development, cucumber Fusarium wilt, control effect