Abstract:

For clarifying the effects of Streptomyces S506 on growth, recovery rate of cold injury leaves and physiological and biochemical characteristics of tomato seedlings under 0℃ cold stress, root activity, leaf conductivity, MDA, proline, protective enzymes SOD and POD were determined with methods of α-naphthylamine, 0.6% thiobarbituric acid, guaiacyl phenol colorimetry, NBT light reduction, and sulfosalicylic acid extraction colorimetry respectively. The results shown that S506 could significantly improve the biomass of tomato seedlings, compared with control, the above and below ground fresh weight increased by 178.98% and 93.18% respectively. Root structure of tomato seedlings also improved, and the hair root number increased two times than control. The recovery rate of cold injury tomato seedlings treated by S506 is 93.48%, however control only 32.52%, root activities increased by 142.00%, proline content increased by 149.56% and SOD activity increased by 24.49%, and relative conductivity and MDA content were decreased by 60.33% and 79.26% respectively. The results indicated that Streptomyces S506 could significantly improve plant growth, as well as the cold stress resistance of tomato seedlings.