何敏 王秀璞 李彦 戴志聪 王从彦 杜海 杜道林

摘 要：为了从青藏高原北部（简称藏北）退化草原的土壤中分离筛选可以促进当地典型牧草生长的促生菌株，以促进藏北植被修复。该文通过采用稀释涂平板的方法，分离耐低温植物促生菌株，并结合盆栽试验设计，评估分离细菌对当地牧草生长的影响。结果表明：（1）从西藏土壤中成功筛选得到两株耐低温细菌TS22和TS27，经16S rRNA基因鉴定分别属于Brevibacterium sp.和Bacillus mycoides。（2）通過离体评估两株分离菌植物促生属性的结果显示，菌株TS22和TS27均具有产生IAA、SID的能力和ACC-脱氨酶活性，TS22具有较高的ACC-脱氨酶活性（264.69 nmol·α-KB mg-1·h-1），TS27显示出较强的产IAA[（7.52±3.85）mg·L-1]和SID（92%）的能力。（3）盆栽试验显示，在10 ℃低温环境下，菌株TS22和TS27对早熟禾和老芒麦生长的影响因植物和菌种的不同而有所不同;菌株TS22在株高、根长、地上和地下干重方面显著促进了早熟禾的生长，且促生能力优于TS27。该研究结果为植物-微生物技术在藏北高寒地区植被恢复中的使用提供了很好的菌种资源和实践基础。

关键词：植物促生菌，低温环境，耐低温菌，植物促生属性，植物修复，草原退化

中图分类号：Q945

文献标识码：A

文章编号：1000-3142（2021）09-1425-08

Abstract：The objective of this study was to screen cold-tolerant plant growth-promoting bacteria （PGPB）for local typical grass in Northern Tibetan Plateau. The serial dilution plating method was used to isolate the PGPB，and pot experiment was designed to evaluate the effect of isolated PGPB on the growth of local grass. The results were as follows：（1）In total，two cold-tolerant PGPB strains named TS22 and TS27 were obtained，which were identified as Brevibacterium sp. and Bacillus mycoides respectively by 16S rRNA gene sequence analysis. （2）Both two strains could produce IAA，SID and ACC-deaminase activity. Strain TS22 showed high ACC-deaminase activity （264.69 nmol·α-KB mg-1·h-1），TS27 displayed higher IAA[（7.52±3.85）mg·L-1] and SID （92%）production ability. （3）Under low temperature （10 ℃），these two isolated PGPB exerted different effects on the growth of Poa annua and Elymus sibericus. Inoculation of strain TS22 significantly improved the growth of Poa annua in plant height，root length，aboveground dry weight，underground dry weight，and showed greater plant growth-promoting activity than strain TS27. This study provides valuable strain resources and experimental basis for application of plant-microbe technique in vegetation restoration in Northern Tibetan Plateau.

Key words：plant growth-promoting bacteria，low-temperature environment，low-temperature-tolerant bacteria，plant growth-promoting properties，plant phytoremediation，grassland degradation

近年来，藏北高原地区由于过度放牧导致草地植被日益退化，已严重威胁当地生态生物多样性、环境健康质量、当地经济发展和人类生活质量水平。因此，加强草地植被保护和修复受到越来越多的关注（Wang et al.，2019）。通过添加化肥、堆肥、高分子材料和腐殖酸等方法，虽然可以有效提高植被修复效率，但因成本高难以实现大规模修复。……