溶磷复合菌剂筛选及其对山核桃幼苗的生物学效应

为探究不同溶磷复合菌剂对山核桃幼苗生物学效应的影响,本研究从山核桃根际土壤中分离获得3株溶磷菌:果胶杆菌Pectobacterium cypripedii(R7)、伯克霍尔德氏菌Burkholderia sp.(R8)、肠杆菌Enterobacter sp.(R9)和4株自生固氮菌株:解聚糖类芽孢杆菌Paenibacillus glycanilyticus(G2)、葡萄球菌Staphylococcus sp.(G3)、假单胞菌Pseudomonas sp.(G4)、芽孢杆菌Bacillus sp.(G5),分别组合筛选出4种复合菌剂(R7G5、R8G4、R8G5、R9G4),并以蒸馏水为对照(CK),将其接种于山核桃幼苗的土壤中,通过测定接种处理后幼苗各项生长和生理指标,评价复合菌株对山核桃幼苗的作用效果。结果显示,R9G4和R8G5复合菌剂在蒙金娜无磷培养基(PVK)连续培养5 d后溶磷量显著高于其他组合。所有复合菌剂对山核桃幼苗均有促生作用;其中R8G5复合菌剂比其他复合菌的总体促生效果更为明显,施用后山核桃幼苗的根长、根面积、总生物量、全磷含量和可溶性糖含量较CK分别增加了105.53%、89.07%、52.94%、55.23%和91.99%;而施用R9G4复合菌剂后山核桃幼苗净光合速率(Pn)和全磷含量的提升效果最佳,较CK分别增加了79.47%和58.16%。本研究结果为进一步研制山核桃苗期促生菌剂提供了理论依据。

Screening the Phosphate-Solublizing Mixing Microbial Inoculums and Their Growth-Promoting Effects on Chinese Walnut Carya cathayensis Sarg. Seedlings

To discover the biological effects of different phosphorus-releasing microorganisms on the seedlings of Chinses walnutCarya cathayensis Sarg., we isolated three phosphate-solubilizing strains (Pectobacterum cypripedii R7, Burkholderia sp. R8, and Enterobacter sp. R9) and four nitrogen-fixing strains (Paenibacillus glycanilyticus G2, Staphylococcus sp. G3, Pseudomonas sp. G4, and Bacillus sp. G5) from the rhizosphere of C. cathayensis. The four mixing inoculums (R7G5, R8G4, R8G5, R9G4) were prepared to use for soil inoculation on C. cathayensis seedlings, to measure the growth and physiological indexes and evaluate the inoculum effects on C. cathayensis seedlings. The treatment with distilled water was included as blank control. The results showed that the release of phosphorus of R9G4 and R8G5 mixture was significantly higher than that of other combinations after cultured in PVK liquid medium for 5 days. The mixing inoculums in the potted inoculation test could promote the growth ofC. cathayensis seedlings, R8G5 was substantially effective than other compound bacteria in promoting the growth of C. cathayensis seedlings. Root indexes such as length, surface area, total biomass, total phosphorus content, and soluble sugar content of C. cathayensis were significantly increased by 105.53%, 89.07%, 52.94%, 55.23% and 91.99% under R8G5 treatment compared with control treatment, resectively. Meanwhile, the R9G4 treatment improved the total phosphorus contents by 58.16% and net photosynthetic rates by 79.47% compared with control treatment, respectively. The results of this study provide an important basis for the further development of growth-promoting mixing microbial agents on C. cathayensis seedlings.