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.

The effects of plant growth regulators alone or in combination on Hexachlorocyclohexane (HCH) phytotoxicity were studied. Waxy corn seeds were immersed in different plant growth regulators that are 1) 2 mg/l Indolebutyric acid (IBA) 2) 2 mg/l Thidiazuron (TDZ) 3) 2 mg/l Gibberellic acid (GA3) 4) 1 mg/l IBA + 1 mg/l TDZ 5) 1 mg/l TDZ + 1 mg/l GA3 and 6) 1 mg/l IBA + 1 mg/l GA3 then sawn in 30 mg/kg HCH-contaminated soil or non-contaminated soil for 10 days. All plant growth regulators could enhance shoot and root dried weight of waxy corn seedlings in non-contaminated soil. Only 2 mg/l GA3 could enhance root length of waxy corn seedlings in non-contaminated soil. In HCH-contaminated soil only 2 mg/l TDZ could increase shoot dried weight of waxy corn seedlings. Also 2 mg/l IBA or 1 mg/l IBA and1 mg/l GA3 could increase root fresh weight of waxy corn seedlings. The exposure with HCH in soil did not affect to shoot and root tissue even though the growth of shoot and root were inhibited. However the exposure with HCH and receive exogenous plant growth regulator induced aerenchyma formation in cortex and pith of waxy corn root.

The usage of wastewater from swine farm for agriculture have study on the production of three plants such as shallot (Allium ascalonicum L.) marigold (Tagetes erecta L.) and ruzi grass (Bachiaria ruziziensis). The experiment was focusing on the growth production and metals accumulation (Pb Cu Fe Zn) in plant. The results shown that swine farm wastewater were a lot of organic substant and nutrient. The biological oxygen demand and chemical oxygen demand were out of standard. The heavy metals lead zinc copper and iron were amount 0.106 0.218 0.082 และ 0.866 mg/kg respectively. The productivity of shallot and ruzi grass were high growing that treated by swine farm wastewater. The marigold production (flower size dry weight and fresh weight) treated by swine farm wastewater found that were not significant from the marigold production that treated by control water. The amount of lead in shallot ruzi grass and marigold flower were out of standard. The shallot and ruzi root found the amount of zinc out of standard. The amount of copper and iron were not out of standard all three plant.