Effects of Different Degrees of PEG Simulated Drought Stress on Seed Germination and Seedling Physiology Characteristics of Cowpea

Effects of different degrees of drought stress on seed germination and seedling physiological characteristics of cowpea( Vigna unguiculata W. ssp. sesquipedalis( L.) Verd.) were investigated using different mass fractions of PEG( 0,50,100,150,200,250,300 g / L) simulated drought stress. The results indicated that the germination rate,germination potential,germination index,bud length,root length and number of lateral roots all showed the trend of decrease with the increase of mass fraction of PEG. The activity of SOD and POD in the seedlings increased when PEG mass fraction used was lower than 150 g / L,but decreased when PEG mass fraction used was higher than 150 g / L. However,the MDA content in the seedlings increased gradually with the increase of mass fraction of PEG. The results show that the higher the degree of drought stress,the higher inhibition on seed germination and seedling growth or more sever damage on cell membrane.