Growth and physiological characteristics of seedlings of soybean drought-resistant mutant M18 under drought stress

To evaluate the growth and physiological characteristics of drought- resistant soybean mutant M18,0%,5%,15%,25% of PEG- 6000 were applied at soybean seedling stage as drought stress conditions. JN18,a wild- type line was selected as control. The results showed that taproot length,number of lateral roots,total length of lateral roots,root volume,root dry weight of both M18 and JN18 increased initially and then decreased with the increasing of PEG concentration; the plant height,crown fresh weight,crown dry weight and RWC gradually decreased; the ratio of root / shoot,Pro content,MDA content,SOD activity and POD activity gradually increased. There was highly significant difference between dry root weight,SOD activity of M18 and J18. M18 had higher water retention,osmotic adjustment ability and enzymatic antioxidant capacity than those of J18 under the same drought stress. These morphological indexes and physiological characteristics including root volume,plant height,crown dry weight,and Pro content,could be used to evaluate drought resistance of soybean.