PHÂN LẬP VÀ TUYỂN CHỌN DÒNG VI KHUẨN NỘI SINH TRONG CÂY LÚA Ở THỪA THIÊN HUẾ

Abstract

The application of endophytic bacteria which has capability of nitrogen fixing, phosphate solubilizing is one of the effective solutions in safe rice production. This research showed that 82 strains were isolated from 120 samples (stems, roots) of rice variety HT1 in towns, districts and Hue city of Thua Thien Hue province on LGI (Lacto-gluco infusion) medium. In which, there were 38 strains from the stems and 44 from the roots. The colonial characteristics of isolated strains were opalescent or transparent white, 1,5 - 7,5 mm in diameter and round with protective covering. They were gram-positive bacterias (+) with rod-shaped or globular cells and had moving ability. There were 27/82 endophytic bacteria strains which can fix the nitrogen and solubilize phosphates. In which, three strains of bacteria (TQP’1, THC1, RKL3) had the highest activity levels. The nitrogen fixation capacity of three strains was 23.8; 14.3; 10.43 mg L^-1 NH⁴⁺respectively. Their phosphate solubility was 129.77; 128.34 and 119.83 mg L^-1 PO₄^3-, respectively. Three strains of bacteria can affect the growth and development of rice plants grown in vitro. Notably, the inoculation of TQP'1 line was the best with high nitrogen fixation and phosphate solubility, so it made a desirable impact on the root length (5.34 - 5.67cm), rhizome (9.64 - 12.36cm) and fresh weight (0.14 g).