抗坏血酸和水杨酸丸衣对NaCl胁迫下紫花苜蓿种子发芽特性的影响

为探究抗坏血酸（AsA）和水杨酸（SA）丸衣对NaCl胁迫下紫花苜蓿种子萌发的缓解效应，以紫花苜蓿种子为试验材料，采用不同浓度的AsA（1、2、4、8 mmol·L^-1）和SA（1、5、10、20 mmol·L^-1）对紫花苜蓿种子拌种后进行丸衣处理（未丸衣种子为CK₁，不做拌种处理的丸衣种子记为CK₂），分析丸衣种子在NaCl胁迫下发芽特性的变化，以期获得能有效缓解紫花苜蓿种子盐胁迫效应的种子丸衣配方。结果表明，1.25%和1.50%的NaCl胁迫显著（P<0.05）降低了紫花苜蓿未丸衣种子的发芽率、发芽势、种苗长和种苗重，延长了平均发芽时间。AsA在1.25%NaCl胁迫下缓解效果不明显，4 mmol·L^-1AsA拌种后丸衣处理，能提高1.50%NaCl胁迫下紫花苜蓿种子的发芽率、种苗长。1 mmol·L^-1SA拌种后丸衣处理，能提高1.50%NaCl胁迫下紫花苜蓿种子的发芽势、发芽率和种苗长，而20 mmol·L^-1SA拌种后丸衣处理降低了紫花苜蓿种子的发芽率。说明AsA和SA丸衣对NaCl胁迫的缓解作用与其拌种浓度和NaCl胁迫浓度有关。本试验筛选出4 mmol·L^-1AsA和1 mmol·L^-1SA拌种丸衣配方对NaCl胁迫的缓解作用最优，该结果为AsA和SA丸衣应用于紫花苜蓿种子缓解NaCl胁迫提供依据。

Effects of ascorbic acid and salicylic acid pelleting on germination characteristics in alfalfa seeds under NaCl stress

This research explored the mitigative effect of ascorbic acid （AsA） and salicylic acid （SA） pelleting against NaCl stress during germination of alfalfa （Medicago sativa） seeds. Alfalfa seeds were coated with various concentrations of AsA （1， 2， 4， and 8 mmol·L^-1） and SA （1， 5， 10， and 20 mmol·L^-1） and then were pelleted. There were two control treatments： CK₁ comprised seeds without coating or pelleting； CK₂ comprised pelleted uncoated seeds. The germination performance of the various seed coating treatments was compared under NaCl exposure at 1.25% and 1.50% concentrations， so as to identify the seed coating formula which most effectively alleviated the effects of salt stress on germinating alfalfa seeds. It was found that the mean germination time was extended and germination percentage， germination potential， seedling length and seedling weight of CK₁ decreased significantly （P<0.05） under NaCl exposure at 1.25% and 1.50% concentrations. AsA had no obvious alleviation effect under 1.25% NaCl stress but the 4 mmol·L^-1 AsA treatment increased the germination percentage and seedling length of alfalfa seeds under 1.50% NaCl stress. The 1 mmol·L^-1 SA treatment increased germination potential， germination percentage and seedling length of alfalfa seeds under 1.50% NaCl stress， while the germination percentage of alfalfa seeds was decreased with 20 mmol·L^-1 SA treatment. These results show that the alleviation effect of AsA and SA coating on NaCl stress was dependent on the concentration of the AsA and SA seed coatings and the level of NaCl stress and that NaCl stress was alleviated in alfalfa seeds by 4 mmol·L^-1 AsA and 1 mmol·L^-1 SA coating and pelleting. These results provide reference data on the mitigation effects of AsA and SA coating and pelleting of alfalfa seeds subject to mitigating NaCl stress.