极端耐盐碱菌株的筛选及其菌肥对盐碱条件下小麦生长和土壤环境的影响

为获得具有盐碱地改良应用潜力的耐盐碱菌株,将采集于东营盐碱地的土样稀释涂布于pH 9、盐浓度100 g·L^-1的Gibbson改良培养基上,共获得18株细菌.通过提高盐浓度、pH值,最终获得在pH 12、盐浓度20%的条件下仍然可以生长的极端耐盐碱菌株N14.对N14进行形态学、生理生化特征和16S rDNA序列分析鉴定,结果表明: 菌株N14为马氏芽孢杆菌.盆栽试验结果表明,与盐碱土(CK)相比,N14菌肥可以显著提高小麦的生物量,株高、鲜重、干重分别提高了21.8%、57.9%、41.7%;显著增加小麦叶绿素a、叶绿素b、叶绿素总量,增长率分别为36.4%、20.0%、31.7%;显著提高盐碱土壤中的蔗糖酶、脲酶和碱性磷酸酶的活性,增长率分别为23.2%、68.8%、106.5%;显著提高小麦根系的超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性,增长率分别为109.6%、17.8%、50%;显著减少小麦根系丙二醛的含量,减少率为39.8%.本研究为极端耐盐碱菌的应用提供了一条新思路,为盐碱地的改良提供了一条新途径.

Screening of extreme salt-alkali tolerant strain and effect of its fertilizer on wheat growth and soil environment under saline-alkali condition.

To obtain salt-alkali tolerant strains which could be potenially used to improve the quality of saline-alkali soil, soil samples collected from Dongying, Shandong Province were diluted and spread to modified Gibbson medium with pH 9 and salt concentration of 100 g·L^-1. A total of 18 bacteria strains were obtained. By increasing salt concentration and pH, an extremely salt-alkali tole-rant strain N14 was screened which could grow at pH 12 and salt concentration of 20%. We analyzed the morphological, physiological and biochemical characters and 16S rDNA sequence of N14. The strain N14 was identified as Bacillus marmarensis. N14 bacterial fertilizer significantly increased the biomass of wheat, improved shoot height, fresh weight and dry weight by 21.8%, 57.9% and 41.7%, respectively. The addition of N14 bacterial fertilizer significantly increased the chlorophyll a, chlorophyll b and total chlorophyll in wheat by 36.4%, 20.0% and 31.7%, respectively. It significantly increased the activities of invertase, urease and alkaline phosphatase in saline-alkali soil by 23.2%, 68.8% and 106.5%, respectively. It also significantly increased the activities of superoxide dismutase, peroxidase and catalase in roots by 109.6%, 17.8% and 50%, respectively. The concentration of malondialdehyde in wheat roots was significantly reduced by 39.8%. This study provided an idea for the application of extreme salt-alkali tolerant bacteria and a way for improvement of saline-alkali soil.