Microbial Inoculation Improves Growth of Oil Palm Plants (Elaeis guineensis Jacq.).

Introduction of diazotrophic rhizobacteria to oil palm tissues during the in vitro micropropagation process establishes an early associative interaction between the plant cells and bacteria. In the association, the diazotrophs provide the host plants with phytohormones and fixed nitrogen. This study was conducted to observe growth of bacterised tissue cultured oil palm plants under ex vitro conditions after 280 days of growth. Root dry weight, shoot dry weight, root volume, bacterial colonisation, leaf protein and chlorophyll content of the host plants were observed. The results revealed that the inocula successfully colonised roots of the host plants. Plants inoculated with Acetobacter diazotrophicus (R12) had more root dry weight and volume than plants inoculated with Azospirillum brasilense (Sp7). Leaf protein and chlorophyll content were higher in the bacterised plants compared to Control 2 plants (inoculated with killed Sp7). These results suggest that the diazotrophs successfully improved the growth of the host plant (oil palm) and minimised the amount of N fertiliser necessary for growth.