Effects of neutral and alkaline salt combined stress on seed germination and seedling growth of two wheat varieties
The wheat varieties 'Xindong 26' and 'Jinshinong 1',which have different levels of salt and al-kali tolerance,were used to study the physiological mechanisms affected by varying concentrations of neutral and al-kaline salts on wheat seed germination and seedling growth.Five concentration gradients ( 0,50,100,200,300 mmol·L-1) were set up under the stress of neutral salt (NaCl) and combined alkaline salt (Na2CO3+NaHCO3,mole ratio 1 ︰ 1),respectively.The effects of salt stress on starch granule morphology,alpha-amylase activity,sol-uble sugar content,relative permeability of plasma membrane,germination index and growth-related indexes during wheat seed germination were studied.The results showed that:(1) Under neutral salt stress,the degradation de-gree of starch grains of 'Xindong 26' was higher than that of 'Jinshinong 1' after 3 days of germination,but the reverse was observed under alkaline salt stress.(2) With the increase of salt stress concentration,compared with the control,the decreasing range of germination potential and rate of 'Xindong 26' under neutral salt stress were 3.37%～78.65%,2.25%～42.70%,respectively,and the decreasing range of germination potential and rate were 19.10%～100.00% and 17.98%～100.00% under the combined alkaline salt stress,respectively.Under neutral salt stress,the decreasing range of germination potential and rate of'Jinshinong 1' was 4.50%～96.63% and 3.37%～95.51%,respectively,under the combined alkaline salt stress,the decreasing range of germination potential and rate were both 2.62%～100.00%.(3) Compared with 'Xindong 26' under neutral salt stress,'Jinshinong 1' had a range of alpha-amylase activity from-25.59%～3.69% and soluble sugar content from-69.00%～184.01%.Com-pared with 'Xindong 26','Jinshinong 1' had a range of alpha-amylase activity from-21.54%～40.48% under combined salt stress,the content of soluble sugar varied from-15.51%～134.67%.(4) The salt tolerancce grade of 'Xindong 26' was higher than that of 'Jinshinong 1' at 200 mmol·L-1 and 300 mmol·L-1 of neutral salt stress,and 'Jinshinong 1 ' was higher than 'Xindong 26 ' at 200 mmol·L-1 of alkaline salt combined stress.(5) The regression equation of salt sensitivity index showed that the critical value of salt tolerance and the lethal limit concentration of neutral salt stress were 258.24 mmol·L-1 and 514.62 mmol·L-1,respectively,and the combined salt stress was 109.47 mmol·L-1 and 280.05 mmol·L-1,respectively.
wheatneutral salt stressalkaline salt combined stressseed germinationseedling growth
万方数据
维普
