Effects of NaCl Stress at Different Concentrations on Germination of Onion Seeds
In order to clarify the effects of different concentrations of NaCl stress on onion seed germina-tion,the simulation test was conducted by designing five different concentrations of NaCl solution as 0(CK),50,100,150 and 200 mmol/L.Three onion varieties,'Zaohuangjin','Tianzheng 105'and'Huoxing 1',were used as materials.The salt tolerance of the three onion varieties was evaluated by analyzing the changes of seed germination potential,seed germination rate,root length,vigor index,salt damage coefficient and so on.The results showed that with the increase of NaCl concentration,the seed germination potential,germination rate and vigor index of the three onion varieties decreased,the root length was shortened in different degrees,and the salt damage coefficient increased.When the concentration of NaCl was 200 mmol/L,the seed germi-nation potential and germination rate of the three onion varieties were significantly different.According to the comprehensive evaluation of the measured indexes,the onion seed germination was sensitive to medium con-centration of NaCl,but had low sensibility to low concentration of NaCl.High concentration of NaCl stress sig-nificantly inhibited the germination of union seeds.The salt tolerance of the three varieties showed'Huoxing 1'>'Tianzheng 105'>'Zaohuangjin'.