Suaeda salsa L. seedlings grown in Hoagland nutrient solution were treated with different concentrations of NaCl combined with two levels of K + (12 μmol/L and 6 mmol/L) to study the K + nutrition effect on plant growth and leaf tonoplast V-H +-ATPase and V-H +-PPase activity. Increase of K + supply in the culture solution markedly increased the fresh weight, dry weight and K + content of S. salsa plants. Western blot analysis showed that the leaf V-H +-ATPase of S. salsa was at least composed of A,B,C,D,E and c subunits, and their expression decreased with the increase of NaCl concentration under K + starvation (12 μmol/L K +), but increased under normal K + application (6 mmol/L K +). Leaf V-H +-PPase molecular weight was about 72.6 kD and its expression increased as NaCl concentration increased under both high or low levels of K + concentration in nutrient solution. There was a positive correlation between of V-H +-ATPase or V-H +-PPase activity and the amounts of their expression. Results in this study suggest that K + nutrition plays an important role in the salt tolerance of S. salsa, and K + is involved in the regulation of V-H +-ATPase or V-H +-PPase activity under salt stress.
[Objective] This study aimed to investigate the salt-tolerance mechanism of sweet potato.[Method]Two sweet potato varieties of Xu 25-2(salt-tolerant cultivar)and Triumph 100(salt-sensitive cultivar)were treated by sodium chloride with the concentration of 0 mmol/L and 100 mmol/L.After 20 days,Na+ content and Na+/K+ ratio in the roots,shoots and leave were determined by the flame photometer,while dry weight and fresh weight of roots,shoots and leave in different varieties were also studied.[Result]The growth of two sweet potato varieties was inhibited under salt stress,so the plant became shorter,leaf and root became fewer,dry weight of roots and leave decreased,but seedlings of Xu 25-2 were inhibited slightly.Furthermore,Na+ content and Na+/K+ ratio in roots,shoots and leaves of two sweet potato varieties increased.Na+ content of salt-tolerant Xu 25-2 was low in roots,shoots and leaves,while Na+ content of salt-sensitive Triumph 100 was high in shoots and leave of seedlings,but the change range of Xu 25-2 was less than that of Triumph 100.[Conclusion]The lower Na+ content and Na+/K+ ratio in leaves under salt stress were the most important characteristics for salt-tolerance of sweet potato varieties.
本实验利用化学诱变剂甲基磺酸乙酯(EMS)处理吸涨的沙枣种子,探讨获得沙枣变异植株的适宜诱变条件.实验设置4个EMS浓度(CK、0.5%、1%、1.5%、2%)和4个诱导时间(2、4、8、12 h),以致死量达到50%为标准.结果表明,EMS诱变抑制了沙枣种子胚的生长,生成的沙枣幼苗干鲜重降低,幼苗根长显著缩短.随着诱变剂量的增大和处理时间的延长,沙枣幼苗的成活率均呈现出显著下降的趋势.以幼苗成活率作为筛选指标,筛选出处理吸涨沙枣种子的最佳EMS诱变条件:EMS浓度为1%,处理时间约为3 h.
