This study was conducted to determine the effects of plant growth regulators on in vitro propagated plantlets and microrhizome inductions of Curcuma comosa Roxb. for an efficient development of plant regeneration. In vitro sprouted shoots (2 cm length) of C. comosa were incised in longitudinal section and subcultured on MS media supplemented with 3 mg/L BA for shoot multiplication and plant regeneration. Subsequently the regenerated plants were transferred to MS medium with various concentrations of plant growth regulators; BA (1 3 5 mg/L) kinetin (1 3 5 mg/L) and TDZ (0.5 1 1.5 mg/L). The result showed that MS medium supplemented with 3 mg/L BA was the most effective in shoot induction with the significantly maximum average number of 2.11 shoot buds per responding explant. Moreover MS medium supplemented with 1 mg/L BA produced the longest average of shoot bud explants (12.99 cm) while the basal MS medium induced the longest average of root multiplication (6.63 cm). Furthermore microrhizome induction was produced under in vitro conditions derived young shoot buds upon transfer to MS medium containing various combinations of 1 3 and 5 mg/L BA and 30 60 and 90 g/L sucrose concentrations. The optimum combination in the induction of significantly highest average length of both stem (18.32 cm) and root (7.52 cm) multiplication was obtained on MS basal medium supplemented with 1 mg/L BA and 30 g/L sucrose for 4 weeks. Although microrhizome formation was not produced by the different amount of BA and sucrose in induction medium starch accumulation was found at the base of the stem explants cultured on MS medium containing 60 and 90 g/L sucrose concentrations. Additionally in vitro propagated C. comosa plantlets through microrhizome induction were grown under greenhouse conditions for 4 weeks and further developed into normal plants resulting in successfully high survival rates of 66 – 100% in the cultivated C. comosa.

The objective of this research was to isolate plant growth promoting rhizobacteria from Wedelia trilobata (L.) A.S. Hitchcock rhizosphere and preliminarily test their plant growth promoting properties such as nitrogen fixation siderophore production phosphate solubilization and indole-3-acetic acid production. Forty-seven bacterial isolates were obtained including 26 isolates of gram positive 18 isolates of gram negative and 3 isolates of actinobacteria. After that 8 isolates (including BWTM1_MSU BWTM2_MSU BWTM5_MSU BWTM6_MSU BWWM6_MSU BWWM8_MSU BWWM9_MSU and BWWM16_MSU) were selected for studying on root colonization and plant growth promoting properties under aseptic condition. The results showed that BWTM5_MSU had the evident on the promotion of plant growth with the most percentage of rice seed germination (63.33%) high level of root and shoot length with 6.11 cm and 3.89 cm respectively. As a result the root and shoot fresh weight was as high as 9.56 mg and 11.33 mg respectively. It also correlated with the highest production of indole-3-acetic acid up to 421.29 ug/ml. The root colonization was studied by counting rhizobacteria isolate BWTM5_MSU from rice rhizoplane and rhizosphere with presented bacterial number at 9.67x106 CFU/g root and 1.64x10 10 CFU/g soil respectively.