耐盐促生菌筛选、鉴定及对盐胁迫小麦的效应

为利用盐碱地微生物促进植物适应盐逆境,从新疆玛纳斯河流域盐碱土壤中分离筛选出的耐盐菌株中,通过测定菌株生长特性及产吲哚乙酸(IAA)、铁载体、溶磷、固氮能力,得到1株耐盐高效促生菌株wp-8;结合形态观察、生理生化及16S rDNA鉴定了其种类;采用室内盆栽试验检测了其对盐胁迫小麦的效应。结果表明,菌株wp-8最适生长温度为30℃,最适生长pH为9,最适生长盐度为5%,吲哚乙酸分泌量为15.90 mg·L~(-1),铁载体相对含量为0.68,溶有机磷及无机磷量分别为0.34 mg·L~(-1)和1.10 mg·L~(-1);鉴定该菌为Nesterenkonia rhizosphaerae。在150 mmol·L~(-1)NaCl胁迫下,小麦种子接种wp-8生长50 d后,与对照相比,小麦株高、根长及根鲜重显著增加(P0.05),增长率分别为9.35%、27.15%、150%;单株鲜重也有所增加,但差异不显著;小麦幼苗根部丙二醛(MDA)含量显著降低(P0.05),超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及叶片脯氨酸(Pro)含量显著增加,分别较对照增加160.63%、30.41%、44.93%、10.04%。说明菌株wp-8可缓解小麦盐胁迫并促进幼苗生长,尤其促进小麦根系的发育。

Screening and Identification of Salt-Tolerant Plant Growth-Promoting Bacteria and Its Promotion Effect on Wheat Seedling under Salt Stress

In order to develop and utilize the saline-alkali microorganisms and provide germplasm resources for promoting crop stress growth. In this study, salt-tolerant strains were isolated and screened from saline-alkali soil in the Manas River Basin of Xinjiang. By measuring the growth characteristics of the strain and the ability to produce acetic acid(IAA), iron carrier, phosphorus solubilization and nitrogen fixation, one salt-tolerant and high-efficiency was determined. The strain wp-8 was combined with morphological observation, physiological and biochemical and 16S rDNA to identify its species. The pot experiment was carried out by indoor salt stress wheat pot experiment. The results showed that the optimum growth temperature of strain wp-8 was 30 °C, the optimum growth pH was 9, the optimum growth salinity was 5%, the indole acetic acid secretion was 15.90 mg·L^-1, and the relative content of iron carrier was 0.68. The dissolved organic phosphorus and inorganic phosphorus were 0.34 mg·L^-1and 1.10 mg·L^-1, respectively, and the strain was identified as Nesterenkonia rhizosphaerae. Under the stress of 150 mmol·L^-1NaCl, the wheat seeds were inoculated with wp-8. After 50 days of growth, the plant height, root length and root fresh weight were significantly increased compared with the control(P<0.05). The rates were 9.35%, 27.15% and 150%, respectively. The fresh weight increased from 0.82 g to 1.01 g, an increase of 23.17%, but the difference was not significant.In addition, inoculating strain wp-8 significantly reduced the content of malondialdehyde(MDA) in roots of wheat seedlings(P<0.05), and increased superoxide dismutase(SOD), peroxidase(POD),catalase(CAT) activity and leaf proline(Pro) content, respectively 160.63%, 30.41% ,44.93%,10.04% higher than control, and the difference reached a significant level(P< 0.05 ). It indicated that strain wp-8 can alleviate the salt stress of wheat and promote the growth of seedlings, especially the development of roots.