种子引发对盐胁迫下高粱种子萌发及幼苗生长的影响

Effect of seed priming on sorghum (Sorghum bicolor L.) seed germination and seedling growth under salt stress

以"Tx623A"×"89-363"(Sb1,耐盐性较弱)和"黑30A"×"大粒早"(Sb2,耐盐性较强)2个高粱杂交组合为试验材料,利用100mmol·L-1NaCl溶液对种子进行引发处理。采用营养液沙培试验,设4个NaCl浓度(0、50mmol·L-1、100mmol·L-1和150mmol·L-1)模拟盐胁迫,研究种子引发处理对盐胁迫下高粱种子萌发及幼苗生长的影响。结果表明:随着盐胁迫强度增加,无论经引发处理还是未经引发处理2个高粱杂交组合种子的出苗时间均明显延迟,出苗率和成苗率下降,幼苗生长受到抑制,物质积累减少。同等盐胁迫强度下,引发处理与未引发处理相比,种子出苗时间缩短,出苗率和成苗率提高,幼苗地上部分干、鲜重和地下部分干、鲜重增加,光合色素含量升高,Na+/K+值显著降低。由此得出,种子引发处理可以不同程度地促进盐胁迫下高粱种子萌发,减轻盐胁迫对幼苗的伤害,促进幼苗生长,提高耐盐性;耐盐性不同的品种引发效果存在差异,对耐盐性较弱的品种引发效果更好。

Seeds of 2 sorghum （Sorghum bicolor L.） hybrid combinations of ＂Tx623A＂ × ＂89-363＂ （Sb1, a weak salt-tolerant cross combination） and ＂Hei30A＂ × ＂Dalizao＂ （Sb2, a strong salt-tolerant cross combination） were primed with 100 mmol·L-1 NaCl. The primed seeds were subjected to salt stresses of 4 NaCl concentrations （0, 50 mmol·L-1, 100 mmol·L-1 and 150 mmol·L-1） in a sand culture experiment. The effects of the seed priming and salt stress on seed germination and seedling growth under salt stress were then investigated. The results showed that with or without priming, seed emergence was significantly delayed. The rates of seed emergence and seedling survival also dropped significantly, while the seedling growth was inhibited, matter accumulation dropped with increased NaCl concentration. Compared with unprimed seeds under the same NaCl concentration, primed seeds had shorter emergence time, higher rates of emergence and seedling survival, higher dry/fresh shoot and root weight, higher contents of photo-synthetic pigments, and lower Na＋/K＋ ratio. The results suggested that seed priming promoted sorghum seed germination under salt stress, alleviated seedling damage by salt stress, accelerated seedling growth and increased seedling salt tolerance. Different effects were noted for cross combinations with different salt tolerance. The effects were much better for weaker salt-tolerant cross combina-tions.