Ce^3+和La^3+对人工老化沙葱种子活力及生理特性的影响

Effects of Ce^3+and La^3+Soaking on Vigor and Physiological Characteristics of Allium mongolicum Seeds Artificially Aged

以未老化和人工老化后的沙葱(Allium mongolicum Regel.)种子为材料,采用氯化铈(Ce3+)和氯化镧(La3+)浸种,测定种子萌发和生理指标,探讨Ce3+和La3+浸种对种子萌发、老化种子活力和生理特性的影响。结果显示:(1)在老化0~5 h时,Ce3+和La3+处理可显著促进沙葱种子萌发,提高种子活力;在老化5 h后,Ce3+和La3+处理对种子萌发无明显促进作用。(2)在老化0~15 h时,Ce3+和La3+处理的沙葱种子中抗氧化酶活性和抗坏血酸(AsA)含量提高,其超氧阴离子自由基(O2-·)产生速率、过氧化氢(H2O2)含量和丙二醛(MDA)含量显著降低;在老化15 h后,Ce3+和La3+处理的种子抗氧化酶活性提高、AsA含量降低,O2-·产生速率和MDA含量提高。(3)在老化5 h时,沙葱种子呼吸速率发生跃变达到最大,Ce3+和La3+处理显著降低了种子呼吸速率。(4)Ce3+和La3+处理在老化0~5 h时提高了沙葱种子超弱发光(UWL)强度,但在老化5 h后沙葱种子的UWL强度降低。研究认为,在沙葱种子人工老化初期,Ce3+和La3+浸种处理可以诱导增强种子抗氧化酶活性和提高AsA含量,有效清除因老化产生积累的过量活性氧(ROS),减轻过氧化伤害,提高种子活力;种子老化中后期,其内部ROS产生与清除系统发生紊乱,加剧了ROS对种子结构的损伤,Ce3+和La3+浸种处理的缓解效应丧失。

The test material was the seeds of Allium mongolicum,which were unaged and artificially aged.Seeds soaking with Ce3+and La3+were used to determine seed germination and physiological indicators,and to explore whether the seed soaking with Ce3+and La3+could promote seed germination and the effect on seed vigor and physiological characteristics of aged A.mongolicum.The results showed that:(1)at 0~5 h of aging,Ce3+and La3+treatment could significantly promote seed germination and improve seed vitality of A.mongolicum;After 5 h of aging,Ce3+and La3+treatment had no significant effect on seed germination.(2)During 0-15 h of aging,antioxidant enzyme activity and AsA content in Ce3+and La3+treated seeds of A.mongolicum were increased,and the accumulation of O2-·generation rate,H2O2 content and MDA content were significantly decreased.After aging for 15 h,antioxidant enzyme activity of Ce3+and La3+treated seeds increased,AsA content decreased,O2-·generation rate and MDA content increased.(3)At 5 h of aging,the seed respiration rate of A.mongolicum reached the maximum,and Ce3+and La3+treatment significantly reduced the seed respiration rate.(4)Ce3+and La3+treatment increased ultraweak luminescence(UWL)intensity of A.mongolicum seeds when aging for 0-5 h,but decreased UWL intensity of A.mongolicum seeds after aging for 5 h.According to the research,in the early stage of artificial aging,Ce3+and La3+seed soaking can induce and enhance antioxidant enzyme activity and AsA content of seeds,effectively remove excessive ROS accumulated due to aging,reduce peroxide damage and improve seed vitality.In the middle and late stage of seed aging,the internal ROS production and clearance system was disordered,which aggravated the damage of ROS to the seed structure,and the alleviating effect of Ce3+and La3+infusion was lost.