一株光合细菌的筛选及促进苦草生长的特性

Screening of a Photosynthetic Bacterium and Its Effect on Promoting the Growth of Vallisneria

筛选光合细菌并探究其对沉水植物的促生效应,以期为促进沉水植物生长提供一种新思路和微生物资源。从江苏长荡湖水样中筛选光合细菌,采用水培试验,研究接种光合细菌和促生细菌Sphingomonas sanguinis YJ11对两种沉水植物(苦草和大苦草)的生长和根活力以及抗氧化酶活性等的影响,比较2种细菌对沉水植物的促生效应。筛选到一株产吲哚-3-乙酸(IAA)、产生物膜并具有溶磷能力的光合细菌N1,经16S rDNA序列分析归属于沼泽红假单胞菌属(Rhodopseudomonas palustris)。结果表明,接种菌株N1和YJ11均促进了两种苦草的生长,且N1的促生效果好于YJ11。菌株N1处理组苦草和大苦草株高、根长、鲜重和干重比对照显著增加15.4%~58.8%,根活力、叶绿素含量显著增加28.4%~47.5%;且两种苦草抗氧化酶活性都显著升高,根系更粗壮健康,根表生物膜明显。光合细菌N1能够更好地促进沉水植物的生长,提高其根活力、抗氧化酶活性和根表生物膜形成,可为微生物促进沉水植物的生长提供理论依据和生物资源。

In order to provide a new idea for promoting the growth of submerged plants,photosynthetic bacteria were screened and their growth promoting effects on submerged plants were investigated.Photosynthetic bacteria were isolated from the water samples of Changdang Lake in Jiangsu.Then a hydroponics experiment was conducted to evaluate the effects of inoculation of the selected photosynthetic bacteria and plant-growth promoting bacteria Sphingomonas sanguinis YJ11 on plant growth and antioxidant enzyme activity of two kinds of submerged plants(Vallisneria natans and Vallisneria gigantea).A photosynthetic bacterium N1 was isolated,which had high efficiency in solubilizing phosphate and producing IAA and biofilm.According to 16S rDNA sequence analysis,the strain N1 belongs to Rhodopseudomonas palustris.The results show that both inoculated strains N1 and YJ11 promoted the growth of the tow plants,among which strain N1 had a more significant effect.Compared with the control,inoculation with strain N1 significantly increased the plant height,root length,fresh weight and dry weight of the two plants by 15.4%-58.8%,and also,significantly increased root activity and chlorophyll content of the two plants by 28.4%-47.5%.Further analysis show that photosynthetic bacteria N1 significantly increased the antioxidant enzyme activities of the root of the two plants and had better biofilm to colonize on root surface.Therefore,these findings demonstrate that photosynthetic bacteria N1 could promote the growth of submerged plants and can be used as elite germplasm resource for producing microbial fertilizer in the future.