In this study,12 strains isolated from the root nodules of woody legumes in the various regions of Jinshajiang River dry-hot valley were used to study the drought-hot tolerance by adding Polythylene glycol 6 000 to YME brouth medium and controlling the temperature.The results indicated that: the 12 strains had different tolerance ability to drought-hot,such as P5-1,P5-6,P5-8,P6-11,Y8-12,P5-5,Y6-13,P5-7,and lots of stains could resistant temperature 40℃ such as P5-1,P5-2,P5-6,P5-7.In the brouth medium which adding PEG,there were a lot of strains had indicated the strong tolerance ability.From this study of resistance,P5-1,P5-6,P5-7 not only could grow at temperature 40℃ but also in the condition of-8.71×10~5 Pa and 35℃.

Much more attention has been paid to the rhizobium,which are symbiotic bacteria forming symbiosis with leguminous plants and conducting nitrogen fixation in the nature.Application of the drought-tolerance of rhizobium to hot-arid regions is helpful to provide means and ideas of improving vegetation growth and promoting productivity of agriculture in these areas.The research advances in drought-resistance of rhizobium were reviewed from the point of physio-chemical view and from the angle of gene engineering.