根瘤菌对广金钱草种子萌发及幼苗生长的影响

Soaking effects of rhizobia on seed germination and seedling growth of Desmodium styracifolium

关键词:  广金钱草, 根瘤菌, 萌发指标, 生长指标, 生理影响

Key words:  Desmodium styracifolium, rhizobia, germination index, growth index, physiological effect

摘要:

为探求促进广金钱草萌发及生长的有效途径,该文使用不同浓度的费氏中华根瘤菌、放射型根瘤菌以及田菁茎瘤固氮根瘤菌菌液分别浸染广金钱草种子,以蒸馏水浸泡种子为空白处理,研究其对广金钱草种子萌发指标(发芽率、发芽势、发芽指数、活力指数)的影响,并在温室培养40、60、80 d后分别测定广金钱草幼苗的生长指标(叶片数、分枝数、株高)及部分生理指标(叶绿素含量、含氮量)的变化。结果表明:(1)在1×10⁷ CFU·mL^-1浓度条件下,三种菌液浸种均获得最大萌发指标,其中田菁茎瘤固氮根瘤菌实验组效果最显著,发芽率、发芽势、发芽指数和活力指数高于对照组16.00%、9.33%、9.51和41.34%。(2)除田菁茎瘤固氮根瘤菌实验组外,其余实验组的广金钱草幼苗叶片数、分枝数及株高均低于对照组。(3)放射型根瘤菌实验组和田菁茎瘤固氮根瘤菌实验组幼苗叶绿素含量相比对照组分别增加1.47%和7.47%,含氮量分别增加0.57%和5.17%。综上所述,三种根瘤菌菌液浸种均可在不同程度上提高广金钱草种子的发芽能力和植株生长期的叶绿素和含氮量,其中田菁茎瘤固氮根瘤菌具有最大正向影响,可有效提高种子萌发能力并促进植株生长。该研究可为不同地区广金钱草的种植和栽培提供技术指导,为开发田菁茎瘤固氮根瘤菌作为植物促生长菌剂提供理论支持。

Abstract:

In order to explore the effective way to promote the germination and growth of Desmodium styracifolium, in this paper, different concentrations of Sinorhizobium fredii, Rhizobium radiobacter, Azorhizobium caulinodans were used to soak the seeds of Desmodium styracifolium,effects of these three kinds of rhizobium solution on the germination indexes(germination rate, germination potential, germination index and vigor index)of D. styracifolium seeds were investigated withthe seeds soaked in distilled water as control check(CK), and the growth indexes(number of blades, number of branches, plant height)and some physiological indexes(chlorophyll content, nitrogen content)of the seedlings were measured after 40, 60 and 80 d after transplant in greenhouse. The results were as follows:(1)Under the concentration of 1×10⁷ CFU·mL^-1, the maximum germination index could be obtained by soaking three kinds of rhizobium solution, among which the best germination rate, germination potential, germination index and vigor index in Azorhizobium caulinodans group were 16.00%, 9.33%, 9.51 and 41.34% higher than those in the control group.(2)The number of blades, number of branches and plant height of the seedlings treated by the Sinorhizobium fredii group and Rhizobium radiobacter group were lower than those of CK group, except for Azorhizobium caulinodans group.(3)The chlorophyll contents of Rhizobium radiobacter group and Azorhizobium caulinodans group increased by 1.47% and 7.47%, respectively, and the nitrogen contents increased by 0.57% and 5.17%, respectively. To sum up, the germination abilities, chlorophyll and nitrogen contents of the seeds of Desmodium styracifolium can be improved in different degrees by soaking the three rhizobia. Among them, Azorhizobium caulinodans group has the most positive effect, which could effectively improve the germination abilities of seeds and promote plant growth. This study can provide technical guidance for the planting and cultivation of Desmodium styracifolium in different areas, and provide theoretical support for the development of Azorhizobium caulinodans as a plant growth promoting agent.