杜氏盐藻促生菌对小白菜耐盐性的影响

Effects of Dunaliella salina on the salt tolerance of Brassica chinensis

[目的]本文研究了杜氏盐藻促生菌(盐单胞菌B3)对小白菜耐盐性的影响,为研制增强植物耐盐性的微生物菌剂奠定基础。[方法]以“奶油四季小白菜”为试验材料,在不同盐浓度下进行水培试验。试验共设4组,分别为无菌水、无菌水+菌液、不同浓度NaCl(100、150、200 mmol·L^(-1))处理组、不同浓度NaCl(100、150、200 mmol·L^(-1))+菌液处理组。盐单胞菌B3添加方式为浇灌方式,每次浇2 mL,每天1次;小白菜种子培养5 d,每天测定记录发芽情况。小白菜幼苗培养25 d后采收,分析生长状况(鲜重)、丙二醛含量、抗氧化酶(超氧化物歧化酶、过氧化物酶和过氧化氢酶)活性以及脯氨酸含量的变化。[结果]正常培养条件下添加盐单胞菌B3可显著促进小白菜发芽、生长及鲜重。与正常培养相比,盐胁迫可明显抑制小白菜发芽与鲜重,造成严重的生理伤害。随着盐浓度的升高(0~200 mmol·L^(-1)),丙二醛含量持续增高,且效应与盐胁迫程度相关;抗氧化酶活性和脯氨酸含量呈先上升后下降的趋势。与对照相比,当盐浓度达到200 mmol·L^(-1)时,小白菜体内抗氧化酶活性不同程度降低,脯氨酸升高幅度显著下降,而添加盐单胞菌B3能在同等盐浓度下显著提高抗氧化酶活性和脯氨酸含量,同时降低丙二醛含量。[结论]高盐胁迫会对小白菜造成严重的生理生化影响,添加盐单胞菌B3能有效缓解盐胁迫引发的氧化及渗透压损伤,从而促进小白菜的发芽及生长。

[Objective]This research investigated the effects of growth-promoting bacteria Halomonas sp.B3 from Dunaliella salina on the salt tolerance ability of Brassica chinensis,and laid the foundation for the development of microbial agents that could enhance salt tolerance of plants.[Methods]The“Cream four seasons Chinese cabbage”variety was selected as the study material,and the hydroponic tests were conducted under different salt stress levels.Four treatments were setup in the experiment:Sterile water(CK),Sterile water+Halomonas sp.B3(PCK),Brassica chinensis treated with different NaCl levels(100 mmol·L^(-1),150 mmol·L^(-1),200 mmol·L^(-1))with or without Halomonas sp.B3 inoculation.Halomonas sp.B3 was added by watering with the volume of 2 mL each time once a day.Plants were cultured for 5 days,and the germination rate was measured and recorded every day.The plants were cultivated for 25 days and harvested,and the fresh weight,malonaldehyde(MDA)concentration,antioxidant enzyme activity and Proline(Pro)content were analyzed.[Results]Under the normal condition,the addition of Halomonas sp.B3 significantly increased the germination rate and fresh weight of Brassica chinensis,while salt stress significantly inhibited the germination and fresh weight,and triggered serious physiological oxidative damage.With the increase of the salt concentration from 0 to 200 mmol·L^(-1),the content of MDA concentration continuously increased,while the antioxidant enzyme activity and the Pro content increased firstly and then decreased.Compared with the control,when the salt concentration reached 200 mmol·L^(-1),the antioxidant enzyme activity in the pakchoi body decreased to varying degrees,and the increase rate of the Pro content was slowed down dramatically.At the same level of NaCl concentration,the addition of Halomonas sp.B3 could significantly activate antioxidant enzyme activities,improve Pro concentration,and reduce MDA content.[Conclusion]Brassica chinensis could suffer serious physiological oxidative damage under high salt stress,while the addition of Halomonas sp.B3 could effectively alleviate the damage and furtherly promote the germination and growth.