褪黑素引发对盐胁迫敖汉苜蓿种子发芽特性的影响

褪黑素(MT)是植物体内存在的一种抗氧化剂,具有调节生长发育和缓解非生物胁迫的作用。试验采用MT溶液(50,100μmmol·L^-1)对敖汉苜蓿种子引发6 h和12 h后,进行盐溶液胁迫处理,筛选MT缓解盐胁迫的适宜引发时间和浓度,研究种子发芽能力和幼苗生长的变化规律。利用NaCl、Na 2SO 4、NaHCO 3、Na 2CO 3配制0,25,50,100,150 mmol·L^-1混合盐溶液(记为ck、25 S、50 S、100 S、150 S),NaHCO 3、Na 2CO 3混合配制0,25,50,100,150 mmol·L^-1碱性盐溶液(记为ck、25 J、50 J、100 J、150 J)。结果表明,低浓度盐溶液(处理25 S)可以显著(p<0.05)提高苜蓿种子发芽率,当盐胁迫浓度超过100 mmol·L^-1时,种子发芽率降至最低,且碱性盐(pH>11.0)显著(p<0.05)抑制种子的发芽。在不同浓度MT引发6 h和12 h时,处理25 S种子发芽率最高,50 J最低。100μmmol·L^-1 MT引发12 h可以显著(p<0.05)提高处理25 S、50 S、50 J种子发芽率。平均发芽时间(MGT)随着盐胁迫浓度的增加,逐渐延长,在100μmmol·L^-1 MT引发12 h时可以显著(p<0.05)缩短处理50 S和50 J种子的MGT。种苗长度和鲜重随着盐浓度的增加呈逐渐下降趋势,均在处理50 J时降到最低,且MT引发12 h时后各处理种苗长度均显著(p<0.05)增加,但种苗鲜重均无显著(p>0.05)差异。确定100μmmol·L^-1 MT引发12 h时,可以有效缓解50 mmol·L^-1混合盐溶液和高pH盐溶液(pH>11.0)的胁迫作用。

Effects of Melatonin Priming on Seeds Germination Characteristics in Aohan Alfalfa under Saline Stress

Melatonin(MT)is an antioxidant that exists in plants,which plays a role in regulating growth and development and alleviating abiotic stress.In order to determine the optimum time and concentration of MT priming for alleviating saline stress,and study the rules of seed germination ability and seedling growth,Aohan alfalfa seeds primed with MT solution(50,100μmol·L^-1)for 6 h and 12 h respectively were adopted as the trial materials for different saline stresses,which mixture saline solutions(0,25,50,100,150 mmol·L^-1 marked with ck,25 S,50 S,100 S,150 S)matched with NaCl,Na 2SO 4,NaHCO 3,Na 2CO 3 and the mixture alkaline-saline solutions(0,25,50,100,150 mmol·L^-1 marked with ck,25 J,50 J,100 J,150 J)did with NaHCO 3 and Na 2CO 3.The results showed that the germination percentage of alfalfa seeds could be significantly(p<0.05)promoted in lowest concentration mixture saline solution(25 S),while decreased to the minimum as the saline concentration exceeded 100 mmol·L^-1,and alkaline-saline solution(pH>11.0)significantly(p<0.05)inhibited the seed germination.The seed germination percentage was the highest in the 25 S and the lowest in the 50 J under MT priming with different concentrations for 6 h and 12 h.The germination percentage of seeds primed by 100μmol·L^-1 MT for 12 h was significantly(p<0.05)increased in the treatments of 25 S,50 S and 50 J.The mean germination time(MGT)gradually prolonged with the increasing concentration of saline stress,and could be shortened significantly(p<0.05)in the treatments of 50 S and 50 J with seeds by 100μmol·L^-1 MT priming for 12 h.The length and fresh weight of seedlings both decreased gradually with the increasing of saline concentration,and went down to the minimum in the 50 J.Although the seedling length in different saline stresses all significantly(p<0.05)increased with MT priming for 12 h,but there was no significant difference(p>0.05)fresh weight of seedlings among saline stresses.It could be suggested that the saline stresses in 50 mmol·L^-1 and higher pH(pH>11.0)saline solutions could be alleviated in alfalfa seeds with 100μmol·L^-1 MT priming for 12 h.