不同胁迫对新疆大叶补血草种子萌发的影响

Effects of Different Stresses on Seed Germination Physiology of Limonium gmelinii in Xinjiang

以分布在新疆北疆境内的大叶补血草为材料,通过模拟野外3种不同胁迫环境(即0~300 mmol/L NaCl溶液、0~150 mmol/L Na_(2)CO_(3)溶液、0~595 mmol/L甘露醇溶液)对种子萌发生理的影响。结果表明,随NaCl浓度增加,种子萌发时间推迟,发芽指数先增加后减少,在50 mmol/L NaCl时最大;随NaCl处理时间的延长,种子发芽势升高,萌发率曲线呈上升趋势并趋于稳定,且在300 mmol/L NaCl处理时,种子萌发率最低;随Na_(2)CO_(3)浓度增加,发芽指数先增加后减少,50 mmol/L Na_(2)CO_(3)处理下最高;随Na_(2)CO_(3)处理时间的延长,种子发芽势增加,且在第10天和第15天保持不变,萌发率曲线呈上升趋势并趋于稳定,30 mmol/L和50 mmol/L Na_(2)CO_(3)处理下,种子萌发率明显高于对照,150 mmol/L Na_(2)CO_(3)处理时,种子萌发率最低;随甘露醇浓度增加,种子萌发时间推迟,发芽指数逐渐降低,在595 mmol/L浓度处理下,种子全程无萌发,与对照相比,Na_(2)CO_(3)和甘露醇胁迫对种子胚根和子叶的生长均有抑制作用,NaCl胁迫对种子子叶生长的抑制作用高于对种子胚根生长的抑制作用;3种不同胁迫处理下,种子SOD活性变化曲线呈“V”型,POD活性变化曲线呈倒“V”型,MDA含量与溶液浓度基本呈正相关关系。研究发现,低浓度的盐胁迫、碱胁迫和渗透胁迫均促进大叶补血草种子的萌发,种子通过调节SOD、POD活性和自身生长,对3种胁迫具有一定的适应能力。

In this study,the material of Limonium gmelinii distributed in northern Xinjiang was selected to investigate the effects of three differently field-simulated stress environments(0-300 mmol/L NaCl solution,0-150 mmol/L Na_(2)CO_(3) solution,and 0-595 mmol/L mannitol solution)on seed germination physiology.The results showed that seed germination time was delayed with the increase of NaCl concentration,and germination index increased first and then decreased and reached the maximum at 50 mmol/L NaCl.In addition,the seed germination potential increased with the extension of NaCl treatment time,and the germination rate curve showed an upward trend and tended to be stable and the seed germination rate was the lowest at 300 mmol/L NaCl treatment.The germination index increased first and then decreased with the increase of Na_(2)CO_(3) concentration,and reached the highest value under 50 mmol/L Na_(2)CO_(3) treatment.Meanwhile,the germination potential of seeds increased with the extension of Na_(2)CO_(3) treatment time and remained unchanged at the 10 th and 15 th days,and the germination rate curve showed an upward trend and tended to be stable.The seed germination rate was significantly higher than that of control,and the seed germination rate was the lowest when treated with 150 mmol/L Na_(2)CO_(3).Seed germination time was delayed and germination index decreased gradually with the increase of mannitol concentration.At the concentration of 595 mmol/L,seeds did not germinate in the whole process,and the germination potential and germination index both were zero.Compared with the control,Na_(2)CO_(3) and mannitol stress inhibited the growth of seed radicle and cotyledon,while NaCl stress inhibited the growth of seed cotyledon more than the growth of seed radicle.The change curve of SOD activity in seeds showed a“V”shape under the three different stress treatments,while the change curve of POD activity showed an inverted“V”shape.The content of MDA was positively correlated with the solution concentration.The results showed that low concentration of salt stress,alkali stress and osmotic stress all promoted the germination of L.gmelinii seeds,and the seeds had certain adaptability to the three kinds of stress by regulating the activities of SOD and POD and their own growth.