油茶溶磷与解钾内生真菌的筛选、鉴定及促生特性分析

Screening,identification,and growth-promoting characteristics of phosphate-solubilizing and potassium-solubilizing endophytic fungi from Camellia oleifera Abel

  • 摘要: 【目的】 筛选油茶的溶磷和解钾内生真菌并对其促生能力进行研究,为研发油茶菌肥、实现油茶可持续高效栽培提供参考依据。【方法】 通过组织分离法从油茶根部分离油茶内生真菌,利用无机磷(PKO)培养基和亚历山大硅酸盐初筛培养基筛选出兼具溶磷和解钾效果的菌株,并进行形态学观察及分子生物学鉴定。利用PKO液体培养基测定其有效磷含量;将溶磷和解钾能力突出的菌株研制成菌肥,分析菌肥对1年生油茶苗的促生效果。【结果】从油茶根部共分离出20株油茶内生真菌,初步筛选出2株能同时产生溶磷圈和解钾圈且表现较优的菌株,分别命名为LP8和YP2。经形态学和分子生物学鉴定,发现菌株LP8为赭绿青霉,菌株YP2为奶灰青霉。菌株LP8和YP2的有效磷含量均在培养5 d时达峰值,分别是447.12和472.13 μg/mL。将溶磷能力突出的菌株YP2研制成菌肥施用于油茶苗,结果显示,与CK相比,施用YP2菌肥油茶苗的苗高、地径、鲜重和干重分别显著增加37.39%、17.67%、19.31%和11.58%(P<0.05,下同),油茶苗的长势和根系活力均得到提高。叶绿素a、叶绿素b和总叶绿素含量较CK分别显著增加20.51%、23.70%和21.70%。施用YP2菌肥后油茶苗的全钾含量显著增加59.81%,土壤中的全氮、全磷含量分别显著增加14.57%和27.70%。施用YP2菌肥后油茶苗根、叶中的可溶性糖和可溶性蛋白含量及超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性较CK均显著增加。【结论】从油茶根部分离筛选获得2株兼具溶磷和解钾能力的真菌菌株LP8和YP2,经鉴定分别为赭绿青霉和奶灰青霉。YP2菌肥可显著促进油茶幼苗的生长发育并提高油茶苗的抗逆性,适配贵州省酸性红壤缺磷区油茶栽培需求,可用于开发油茶专用微生物肥料。

     

    Abstract: 【Objective】 To screen phosphate-solubilizing and potassium-solubilizing endophytic fungi of Camellia oleifera Abel and investigate their growth-promoting capacity, which could provide theoretical basis for developing special microbial fertilizers and realizing sustainable and high-efficiency cultivation of Camellia oleifera Abel.【Method】 Endophytic fungi were isolated from the roots of Camellia oleifera Abel via the tissue isolation method. Strains with both phosphate-solubilizing and potassium-solubilizing capacities were preliminarily screened using inorganic phosphate (PKO) medium and Aleksandrov silicate medium, followed by morphological observation and molecular biological identification. The available phosphorus content was determined in liquid PKO medium. The strain with outstanding phosphate-solubilizing and potassium-solubilizing capacities was prepared into microbial fertilizer, and its growth-promoting effects on one-year-old Camellia oleifera Abel seedlings were analyzed. 【Result】 A total of 20 endophytic fungal strains were isolated from Camellia oleifera Abel roots. Two strains (designated LP8 and YP2) with obvious phosphate-solubilizing and potassium-solubilizing halos and superior comprehensive performance were obtained through primary screening. Morphological and molecular identification confirmed that strain LP8 was Penicillium ochrochloron, and strain YP2 was Penicillium cremeogriseum. The available phosphorus contents of LP8 and YP2 strains both peaked on the 5th d of incubation, reaching 447.12 and 472.13 μg/mL respectively. The high-efficiency phosphate-solubilizing strain YP2 was made into microbial fertilizer and applied to Camellia oleifera Abel seedlings. Compared with CK, seedling height, ground diameter, fresh weight, and dry weight of seedlings treated with YP2 microbial fertilizer increased significantly by 37.39%, 17.67%, 19.31%, and 11.58% (P<0.05, the same below); seedling growth status and root activity were remarkably improved. Chlorophyll a, chlorophyll b, and total chlorophyll contents rose significantly by 20.51%, 23.70%, and 21.70% compared to CK. The total potassium content of Camellia oleifera Abel seedlings treated by YP2 microbial fertilizer increased by 59.81%, while the soil total nitrogen and total phosphorus contents significantly increased by 14.57% and 27.70% respectively. In roots and leaves of YP2 microbial fertilizer treated seedlings, soluble sugar, soluble protein contents, as well as superoxide dismutase (SOD) and catalase (CAT) activities were all significantly higher than those of CK. 【Conclusion】 Two endophytic fungal strains LP8 and YP2 with dual phosphate-solubilizing and potassium-solubilizing capacities are isolated and screened from Camellia oleifera Abel roots, identified as Penicillium ochrochloron and Penicillium cremeogriseum respectively. YP2 microbial fertilizer can significantly boost the growth and development of Camellia oleifera Abel seedlings and enhance their stress resistance. It is suitable for Camellia oleifera Abel cultivation in phosphorus-deficient acidic red soil areas of Guizhou, and can be developed as a special microbial fertilizer for Camellia oleifera Abel.

     

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