Penggunaan Mycorrhizal Helper Bacteria (MHBs) dan Fungi Mikoriza Arbuskula (FMA) Untuk Meningkatkan Perturnbuhan Semai Mindi (Melia azedarach Linn.)

Abstract

Introduction. High rate of forest degradation in Indonesia causes reduction of forest area and increase of critical land area. In the efforts to reduce the impacts from such forest damage. land and forest rehabilitation is conducted. However, the main constraint for the success of rehabilitation is the retarded growth of planting stocks (seedlings) and low survival rate of the seedlings. For overcoming such problem, good quality seedlings, which could survive in marginal lands are required. For obtaining good quality seedlings which have high survival rate in the field, there is a need for sufficient input of nutrients through fertilizer application. The applied fertilizer should be environmentally friendly. The use of soil microbe technology, namely the use of mycorrhiza is an appropriate solution and has been proven to be able to increase plant growth. One of the mycorrhizal fungi which can be used as biofertilizer is AMF (Arbuscular Mycorrhizal Fungi). Symbioses between fungi and plant roots often suffer some constraints in the field. Therefore, there is a need for microorganism which could give positive effects for improving such cooperation. Such organism is bacteria species which is known as Mycorrhizal Helper Bacteria (MHBs). MHBs is a specific bacteria which is able to have symbioses with AMF and is able to stimulate the development of AMF. The application of MHBs and AMF on mindi is expected to be able to increase the growth and quality of mindi seedlings. Methodology. A completely randomized design two factors (Micorrhizal and Bacteria) was employed to examine the effect of mycorrhizal and bacteria on the plant growth. The parameter observed were: mycorrhiza infection percentage, height, diameter, shoot biomass, root biomass, shoot - root ratio and Index of Seedling Quality (1MB). Results and conclusion. Isolate of bacteria BGG02 which was combined with AMF Gigaspora sp (M2) gave the highest increase in mycorrhiza infection percentage, namely 58.3% as compared to mycorrhiza treatment without bacteria. Isolate BGG03 was more effective in increasing the mycorrhiza infection percentage if combined with Glomus sp (M1), namely 18.8%, whereas application of isolates BGG01 and BGG04 increased the percentage of mycorrhiza infection 1.8% when combined with mixture of AMF Glomus sp and Gigaspora sp (M1 M2). Application of bacteria, AMF or combination of them, gave positive effects toward mindi growth. Combination of isolate BGG01 and AMF Gigaspora sp (M2B1) gave the best respond toward parameters of height, diameter, root biomass, shoot biomass and Index of Seedling Quality (1MB), with increase value of respectively 352.7%, 4.8%, 2809.7%, 4545.7% and 488.3% as compared to control. In general, during the application of AMF, application of Gigaspora sp (M2) gave the greatest positive effect toward mindi growth as compared with application of other AMF, namely Glomus sp (M1) and mixture of Glomus sp and Gigaspora sp (M1 M2).