The Use of rhizobia and vesicular-arbuscular mycorrhiza to improve drought resistance of Kudzu (Pueraria phaseoloides (Roxb.)Benth.) in coastal land

Abstract

A study was conducted to examine the association between Rhizobium and VAM fungi on the kudzu plant growth and response to drought stress in coastal dry land. The research was carried out in three phases: (1) germination of kudzu seeds; (2) multiplication of VAM and Rhizobia inoculums; and (3) inoculation of fungi and/or bacteria on plants grown at various soil moisture content. At the inoculation phase, the pot experiment was carried out for 8 weeks with a pot experiment arranged based on a 4 x 4 treatment factorial Completely Randomized Design with three replications to test the source of the inoculum and soil moisture content (25%, 50%, 75%, 100%). Observations were made on: (1) Rhizobial infection activity and nodulation; (2) VAM infection activity; (3) plant growth, and 4) population dynamics of rhizobacteria. The results showed that the rhizobia inoculation alone was not able to increase the bacterial infection activity and root nodulation, the VAM fungal infection, and plant growth. Inoculation with VAM fungi alone was able to stimulate infection activity of nodule-forming bacteria and root nodulation, VAM fungal infection activity, and plant growth. The combination of VAM fungal and rhizobial inoculation was able to stimulate fungal infection activity and growth of plant roots and shoots, but not always able to stimulate bacterial infection activity and root nodulation. Inoculation of VAM fungi alone was able to stimulate the plant growth rates even up to a drought stress level of 75%. This means that inoculation of VAM fungi alone was able to increase drought resistance and maintain the plant growth rates at high levels of drought stress.