摘要
【目的】比较氯化钙、ABA和蔗糖预处理对解除休眠水曲柳种子低温脱水萌发的影响,并探索在不同预处理条件下脱水过程中种子内部的生理变化,为揭示种子脱水耐性调控的生理机制提供参考依据。【方法】以解除休眠的水曲柳种子为材料,利用不同浓度(10^(-2),10^(-3),10^(-4),10^(-5) mol·L^(-1))的氯化钙溶液、不同浓度(10-3,10-4,10-5,10-6mol·L^(-1))的ABA溶液或不同质量浓度(1,10,50,100 g·L^(-1))的蔗糖溶液浸泡种子24 h,以蒸馏水浸泡种子24 h为对照,比较不同处理种子在低温(5℃)条件下干燥脱水后的萌发能力,确定几种预处理措施对种子低温脱水萌发的影响。再依据上述试验结果,分别选择出提高种子萌发能力最有效的处理浓度:氯化钙10-3mol·L^(-1)、ABA 10-6mol·L^(-1)、蔗糖100 g·L^(-1),以经上述溶液预处理24 h后低温脱水的种子为材料,以蒸馏水浸泡24 h后低温脱水种子为对照,进行种子浸出液相对电导率、种子抗氧化酶(SOD、POD和CAT)活性、丙二醛(MDA)含量、可溶性糖、可溶性蛋白和淀粉含量测定,分析不同预处理措施对种子细胞膜透性、抗氧化系统酶活性和贮藏物质代谢的影响。【结果】10-3mol·L^(-1)氯化钙或10-6mol·L^(-1)ABA预处理可显著提高种子在低温(5℃)下脱水后的发芽率和发芽指数,缩短发芽时间;100 g·L^(-1)的蔗糖预处理可显著提高种子在低温(5℃)下脱水后的发芽率,但在提高发芽指数和缩短发芽时间上并没有明显效果。10-3mol·L^(-1)氯化钙预处理的种子,胚中SOD活性在低温脱水后显著提高,种子相对电导率和MDA含量显著降低;10-6mol·L^(-1)ABA预处理的种子,低温脱水后胚中POD活性明显提高,种子相对电导率和MDA含量显著降低;100 g·L^(-1)蔗糖预处理的种子,低温脱水后胚中SOD和POD活性均显著提高,种子相对电导率和MDA含量显著降低。氯化钙、ABA或蔗糖预处理,显著降低了种子胚和胚乳中可溶性蛋白的含量,显著提高了胚中可溶性糖的含量。【结论】适宜浓度的氯化钙(10-3mol·L^(-1))、ABA(10-6mol·L^(-1))和蔗糖(100 g·L^(-1))预处理(尤其是氯化钙或ABA预处理)能够提高水曲柳种子低温脱水后的萌发能力。氯化钙、ABA和蔗糖预处理,会显著提高低温脱水条件下种子胚中的抗氧化系统酶活性,更好地维持细胞膜结构的完整性,降低细胞的离子外渗和MDA含量。但不同预处理种子胚中的抗氧化酶活性表现不同,氯化钙预处理提高胚中SOD活性的作用更明显,ABA预处理提高胚中POD活性的作用更明显,而蔗糖预处理则同时提高胚中的SOD和POD活性。氯化钙、ABA和蔗糖预处理后低温脱水过程中种子胚中可溶性糖含量显著增加,这可能是种子低温条件下脱水保护功能提高的原因之一。
【Objective】 We compared the effects of CaCl2,ABA and sucrose pretreatment on germination of Fraxinus mandshurica dormancy-released seeds dehydrated at low temperature,and explored the intrinsic physiological changes of seeds during dehydration under different pretreatment conditions to reveal the physiological mechanism of regulation and control of seed desiccation tolerance.【Method】 The dormancy released seeds of F. mandshurica were used to investigate seed germination ability after dehydration at low temperature( 5 ℃) pretreated by different concentrations( 10-2,10(-3),10(-4),10(-5)mol·L(-1)) of CaCl2 solution,different concentrations( 10(-3),10(-4),10(-5),10(-6)mol·L(-1)) of ABA solution or different mass concentrations( 1,10,50,100 g·L(-1)) of sucrose solution for 24 hours,the seeds were soaked in distilled water for 24 hours as control. According to the above experimental result,the best treatment concentration to improve the seed germination ability,CaCl210(-3)mol·L(-1),ABA 10(-6)mol·L(-1)and sucrose 100 g·L(-1),were selected respectively.Then,the seeds dehydrated at low temperature after pretreating with the selected solution for 24 hours were used for this study,and the seeds soaked in distilled water for 24 hours were used as control,the effects of different pretreatment methods on seed cell membrane permeability,antioxidant enzyme activity and storage material metabolism were analyzed by measuring the relative electrical conductivity,the activities of antioxidant enzymes( SOD,POD and CAT),the malondialdehyde( MDA) content,soluble sucrose,soluble protein and starch content in the seeds.【Result】Pretreatment of 10(-3)mol·L(-1)CaCl2 or 10(-6)mol·L(-1)ABA could significantly improve the germination rate and germination index of the seeds after dehydration at low temperature( 5 ℃),and shorten the seed germination time; pretreatment of 100 g·L(-1)sucrose could significantly improve the seed germination rate after dehydration at low temperature( 5 ℃),but had no significant effect on the germination index and the germination time. For the seeds pretreated with 10(-3)mol·L(-1)CaCl2,the SOD activity in embryos was significantly increased after dehydration at low temperature( 5 ℃),and the relative electrical conductivity and MDA content in seeds were significantly decreased; For the seeds pretreated with 10(-6)mol·L(-1)ABA,the POD activity in embryos was significantly increased after dehydration at low temperature( 5 ℃),and the relative conductivity and MDA content in seeds decreased significantly; For the seeds pretreated with 100 g·L(-1)sucrose,the SOD and POD activity in embryos were significantly increased after dehydration at low temperature( 5 ℃),the relative conductivity and MDA content in seeds decreased significantly. CaCl2,ABA and sucrose pretreatment significantly reduced the soluble protein content, and increased the content of soluble sugar in seed embryo and endosperm.【Conclusion】The appropriate concentration of CaCl2( 10(-3)mol·L(-1)),ABA( 10(-6)mol·L(-1)) and sucrose( 100 g·L(-1))pretreatment( especially CaCl2 or ABA pretreatment) can improve the germination ability of Fraxinus mandshurica seeds after dehydration at low temperature. Under low temperature dehydration conditions, CaCl2, ABA and sucrose pretreatment can significantly improve the antioxidant system enzyme activity in the seed embryo,better maintain the integrity of cell membrane structure,reduce ion leakage and MDA content of cells. But the antioxidant enzyme activities in different pretreated seeds were different. Pretreatment with CaCl2 was more beneficial to improve the activity of SOD in embryos,and ABA pretreatment was more beneficial to improve the activity of POD in embryos, while sucrose pretreatment increased the activity of SOD and POD in embryos at the same time. The improvement of the protective function in the low temperature dehydration process by pretreatment of CaCl2,ABA and sucrose was probably related to the increase of the soluble sugar in embryos.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2017年第7期54-61,共8页
Scientia Silvae Sinicae
基金
国家自然科学基金项目(31000301)
关键词
氯化钙
ABA
蔗糖
脱水耐性
种子萌发能力
细胞膜透性
抗氧化酶活性
CaCl2
ABA
sucrose
dehydration tolerance
seed germination ability
cell membrane permeability
antioxidant enzyme activity