兼具水稻纹枯病拮抗功能的生物水稻育苗基质效果研究

水稻纹枯病是水稻上常见的土传病害之一,为了研发出可防治水稻纹枯病兼具促生效果的功能型生物水稻育苗基质,本研究选用前期筛选出具有固氮解磷功能的根际促生菌:LY5枯草芽孢杆菌(Bacillus subtilis)、LY11解淀粉芽孢杆菌(Bacillus amyloliquefaciens)、X2摩拉维亚假单胞菌(Pseudomonas moraviensis)、X3沙芬西芽孢杆菌(Bacillus safensis)、X8绿针假单胞菌(Pseudomonas chlororaphis),首先探索该5株促生菌对水稻纹枯病病原菌的抑菌率,再将其与水稻纹枯病病原菌混合,在实验室已筛选出的最适配比基质基础上,研发功能型生物水稻育苗基质。在盆栽条件下,与市售水稻育苗基质对比,验证功能型生物水稻育苗基质对水稻纹枯病发病率、水稻幼苗生长和体内抗性相关酶类的影响。结果表明:(1)5株根际促生菌对水稻纹枯病病原菌均具有拮抗作用,抑菌率达到35.31%～40.20%。(2)5株拮抗促生菌能够降低水稻纹枯病的发病率,其中添加LY11菌株的处理较对照处理的每盘出苗数显著增加了110.41%,而发病率显著降低了89.32%。(3)在含有水稻纹枯病病原菌的育苗基质中添加拮抗促生菌后,水稻幼苗的茎粗、百株地下部干物质重、百株全株干物质重、根系活力、根总表面积、根平均直径、根总体积、根尖数等方面均有所提高,其中添加LY11菌株的处理比市售水稻育苗基质处理分别显著提高3.13%、4.21%、4.97%、68.02%、26.77%、16.67%、44.44%、7.82%。(4)添加拮抗促生菌显著促进了水稻幼苗对地上和地下部氮磷钾的吸收。(5)水稻幼苗体内超氧化物歧化酶、过氧化物酶、过氧化氢酶的活性以及丙二醛的含量均显著高于市售水稻育苗基质处理,提高幅度为27.08%～122.72%、16.09%～48.15%、53.33%～233.85%、110.24%～511.71%。因此,本研究研发出5种对水稻纹枯病具有较好的拮抗效果,同时可以显著促进水稻幼苗生长的功能型高效生物水稻育苗基质,其中添加了菌株LY11的育苗基质综合效果最优,为功能型高效生物水稻育苗基质的研制与应用奠定了理论与实践基础。

Study on Effect of Biological Rice Breeding Substrate with Antagonistic Function of Rice Sheath Blight

Rice sheath blight is one of the common soil-borne diseases of rice. To develop a biological rice breeding substrate to prevent and control rice sheath blight and promote rice growth, 5 rhizosphere growth-promoting bacteria with nitrogen fixation and phosphorus removal functions were selected, including LY5 (Bacillus subtilis), LY11 (Bacillus amyloliquefaciens), X2 (Pseudomonas moraviensis), X3 (Bacillus safensis) and X8 (Pseudomonas chlororaphis). Based on the determination of the inhibition rate, the 5 bacteria were mixed with pathogenic bacteria of rice sheath blight, and then the functional biological rice breeding substrates were developed on the basis of the most suitable substrates screened in the laboratory, and a pot experiment was conducted to verify the effects of the developed 5 substrates on the incidence rate of rice sheath blight, growth of rice seedlings and in vivo resistance-related enzymes in rice by comparing with a commercial rice breeding substrate (CK). The results showed that the 5 rhizosphere growth-promoting bacteria all had the antagonistic effect on the pathogen of rice sheath blight with the inhibition rate from 35.31% to 40.20%. Compared with CK, the 5 rhizosphere growth-promoting bacteria all reduced the incidence rate of rice sheath blight, among of which, LY11 treatment significantly reduced the incidence rate by 89.32% and increased the number of emergence per plate by 110.41%. The 5 rhizosphere growth-promoting bacteria increased rice stem diameter, underground dry matter weight of 100 plants, dry matter weight of 100 plants, root activity, total root surface area, average root diameter, total root volume and root tip number, among of them, compared with CK, LY11 treatment significantly increased the above indexes by 3.13%, 4.21%, 4.97%, 68.02%, 26.77%, 16.67%, 44.44% and 7.82%, respectively. Compared with CK, the 5 rhizosphere growth-promoting bacteria significantly promoted the uptake of nitrogen, phosphorus and potassium by rice seedlings, increased significantly the activities of superoxide dismutase, peroxidase and catalase and the content of malondialdehyde in rice seedlings by 27.08%-122.72%, 16.09%-48.15%, 53.33%-233.85% and 110.24%-511.71%, respectively. Therefore, the 5 rhizosphere growth-promoting bacteria have good antagonistic effect against rice sheath blight pathogens and Bacillus amyloliquefaciens has the best comprehensive effect, it lays a theoretical and practical basis for developing the high efficient biological rice breeding substrate with growth-promoting and bio-control functions.