广西喀斯特地区植物根际土壤解磷菌筛选及促生效应研究

Screening of Phosphate Solubilizing Bacteria and Growth Promoting Effect in Rhizosphere Soil of Karst Area in Guangxi

关键词:  喀斯特  解磷菌  根际促生菌  植被修复

Key words:  karst  phosphate solubilizing bacterial strains  plant rhizosphere bacteria  vegetation restoration

摘要:

[目的]广西喀斯特石漠化地区水土流失和植被退化严重，土壤有效磷含量低是限制植被修复的因素之一，筛选乡土高效解磷菌株，可以加快修复石漠化生态环境。[方法]通过调查筛选石漠化地区常见植物根际土壤解磷菌，检测解磷菌株解磷能力，并将优良菌株培养后接种至顶果木（Acrocarpus fraxinifolius）幼苗根际土壤，检测解磷菌对植物的促生效应。[结果]石漠化地区土壤中解磷微生物丰富，共筛选出20株解有机磷菌和24株解无机磷菌，分别属于11个类群，其中，假单胞菌属（Pseudomonas）为石漠化植物根际土壤解磷菌的优势类群。解有机磷菌解磷能力为35.4~79.2 μg/mL，解无机磷菌解磷能力为112~253.2 μg/mL。接种解磷菌剂对顶果木生长和养分吸收具有显著促进作用，植株地上生物量比对照增加14.5%~30.5%，根系生物量比对照增加27.6%~45.7%。接种IP-HLG1和IP-CTM11处理的植株氮、磷含量显著高于对照处理，分别比对照处理高9.3%、19.7%和24.6%、20.3%。与对照处理相比，接种菌剂处理土壤有效磷含量增加了34.5%~69.1%，IP-HLG1和IP-CTM11处理增加显著。[结论]石漠化土壤中解磷菌以假单胞菌属为优势类群，筛选的解磷菌株IP-HLG1和IP-CTM11对顶果木幼苗生长具有显著促进效应，对石漠化土壤磷元素活化能力较强，可作为研发微生物肥料的潜在功能菌株。

Abstract:

[Objective] The low available phosphorus content in soil is one of the limiting factors for local vegetation restoration. Screening the high efficiency phosphate solubilizing bacterial strains can speed up the restoration of rocky desertification ecological environment.[Methods] In this study,the phosphate solubilizing bacterial strains of the common plant rhizosphere soil in the rocky desertification area were investigated and screened,the phosphate solubilizing ability of phosphate solubilizing bacteria was detected,and the excellent strains were inoculated to the Acrocarpus fraxinifolius seedlings,and the effect of phosphate solubilizing bacterial strains on plant growth was detected.[Results] The results showed that phosphate solubilizing microorganisms were abundant in the rocky desertification area,and 20 strains of organophosphorus and 24 inorganic phosphate solubilizing bacterial strains were screened out,which belonged to 11 groups,respectively. Among them,Pseudomonas was the dominant group in the rhizosphere soil of rocky desertification plants. The phosphate solubilizing ability of organophosphorus bacteria was 35.4~79.2 g/mL and the phosphate solubilizing ability of inorganic phosphorus bacteria was 112~253.2 g/mL. The inoculation of phosphate solubilizing bacteria significantly promoted the growth and nutrient absorption of the A.fraxinifolius seedlings. Compared to the control seedlings,the aboveground biomass increased by 14.5%~30.5%,and the root biomass increased by 27.6%~45.7%. The nitrogen and phosphorus contents of the plants treated with IP-HLG1 and IP-CTM11 were significantly higher than those of the control treatments,which were 9.3%,19.7%,24.6%,and 20.3% higher than those of the control treatment,respectively.Compared to the control treatments,the soil effective phosphorus content in IP-HLG1 and IP-CTM11 treatments increased most significantly.[Conclusion] Preliminary studies showed that Pseudomonas was the dominant group of phosphate solubilizing bacteria in rocky desertification soil. The screened phosphate solubilizing bacterial strains IP-HLG1 and IP-CTM11 played a significant role in promoting the growth of A.fraxinifolius seedlings. These two strains had strong ability to activate available phosphorus in soil and could be used as potential functional strains for developing microbial fertilizers.