香椿种子特定贮藏条件下活力变化的研究

Study on the Seed Vigor of Toona sinensis under Specific Storage Conditions

[目的]通过对不同贮藏条件下香椿种子发芽指标、抗氧化酶活性等测定分析,探索种子含水量和贮藏温度对香椿种子生理生化特性的影响,为香椿种子的贮藏方法提供技术支持。[方法]利用100%湿度环境获得9.1%、12.2%、14.0%、15.8%和17.8%五个含水量的香椿种子,在10、15、和20℃下分别贮藏90 d,每30 d测定种子发芽率和抗氧化酶活性等指标。[结果]在相同贮藏条件下,随贮藏时间延长,种子发芽率、活力指数、过氧化氢酶(CAT)和过氧化物酶(POD)活性逐渐下降,超氧化物歧化酶(SOD)活性先升后降,浸出液电导率和丙二醛(MDA)逐渐上升。经90 d贮藏,随种子含水量或贮藏温度的升高,香椿种子发芽率和活力指数呈下降趋势,浸出液电导率和MDA含量显著上升,种子中SOD、POD和CAT活性均随贮藏时间的延长而显著下降。[结论]种子浸出液电导率和MDA含量与香椿种子发芽率呈显著负相关,抗氧化系统酶活性与发芽率呈显著正相关,膜质过氧化作用是引起香椿种子老化劣变的重要原因之一。本研究得出的香椿种子安全贮藏条件为:当温度不超过15℃时,含水量应控制在12.2%以下,当温度在15～20℃时,含水量应低于9.1%。

[Objective] To study the effects of seed moisture content and storage temperature on the physiological and biochemical characteristics of Toona sinensis by analyzing the germination index and antioxidant enzyme activity, so as to provide references for the storage method of T. sinensis seed.[Method] The seeds of Toona sinensis with five water contents of 9.1%, 12.2%, 14.0%, 15.8% and 17.8% were obtained under 100% humidity environment and stored for 90 days at 10℃, 15℃ and 20℃. The seed germination rate and antioxidant enzyme activity were measured every 30 days.[Result] Under the same storage conditions, the seed germination percentage, vigor index, CAT activity and POD activity decreased gradually with the increase of storage time, and the SOD activity increased at first and then decreased, the conductivity and the content of MDA went up gradually. After 90 days of storage, with the increase of water content or temperature, the seed germination percentage and vigor index of T. sinensis decreased, the conductivity and MDA content of the extract increased significantly. The activities of SOD, POD and CAT decreased significantly with the deepening of aging.[Conclusion] Both conductivity and MDA content indexes are significantly and negatively correlated with germination percentage. Antioxidant enzyme activity is significantly and positively correlated with germination percentage. Membrane lipid peroxidation is one of the important reasons for aging deterioration of T. sinensis seed. The safe storage conditions of T. sinensis seed in this experiment are as follows:when the temperature does not exceed 15℃, the water content should be controlled below 12.2%;when the temperature is between 15℃ and 20℃, the water content should be below 9.1%.