以珍稀濒危植物胡杨种子为材料,采用硅胶脱水的方法制备不同含水量的种子,再经不同相对湿度的溶液对种子进行回湿处理,确定最适含水量及最适回湿方法;对最适含水量种子进行50 ℃高温老化处理,经回湿后测定各种酶活性、可溶性糖、可溶性蛋白及丙二醛含量,考察超干保存的效果,明确超干保存胡杨种子的可行性.结果表明:(1)当胡杨种子含水量降至3.4%时,其发芽率开始显著下降,但经回湿处理后的发芽率和发芽指数可恢复至未经超干处理样品的水平.(2)采用4种不同的方法对含水量为3.4%的种子进行回湿处理,各回湿方法处理的种子发芽率和发芽指数均显著高于未回湿处理,并以先用饱和CaCl2回湿12 h后再用饱和NH4Cl回湿12 h的处理效果最佳.(3)在50 ℃高温老化处理过程中,超干处理(含水量为3.4%)和未超干处理的胡杨种子过氧化物酶、过氧化氢酶、脱氢酶活性以及可溶性糖的含量均逐渐降低,而丙二醛的含量则逐渐升高,但超干处理种子的升降幅度明显较小.研究认为,胡杨种子超干处理的最适含水量为3.4%,超干处理种子较适宜的回湿方法是饱和CaCl2和饱和NH4Cl依次回湿处理各12 h,超干处理可使胡杨种子抗氧化酶活性和可溶性糖含量于老化过程中维持在相对较高水平,膜系统伤害较轻,从而提高种子的抗老化能力,说明超干保存胡杨种子具有一定的可行性.%The ultra-dry preservation of the rare and endangered species Populus euphratica seeds was carried out to determine the optimal moisture content and rewetting method in this paper.The feasibility of ultra-dry preservation of P.euphratica seeds was determined by measurements of contents of various enzymes,soluble sugar and malondialdehyde(MDA).The P.euphratica seeds with different water contents were prepared by the method of dehydration of silica gel.The seeds were re-wetted with different solutions,and the optimal wetting method was selected.After treated by aging,the activities of enzymes,soluble sugar,and malondialdehyde in the optimum moisture content of seeds were determined after rewetting to determine the effect of ultra-dry preservation.The results showed that: (1) the seed germination rate decreased with the water content decreased to 3.4%.The seed germination rate and germination potential of P.euphratica seeds could be restored to the samples without ultra-dry treatment after re-wetting.The optimum moisture content was determined as 3.4%.(2) After comparison of four different methods,the results showed that re-wetting with saturated NH4Cl for 12 h after re-wetting with saturated CaCl2 was a better method of re-wetting.(3) The aging results showed that the suitable ultra-dry treatment could increase the activities of peroxidase,catalase,dehydrogenase and the content of soluble sugar,and decrease the content of MDA in the seeds with 3.4% moisture at 50 ℃.Therefore,ultra-dry preservation of P.euphratica seeds has a certain feasibility for enhancing the anti-aging ability of the seeds.
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