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为了揭示花粉超低温保存的生理机制,本研究以玉兰花粉作为试验材料,对花粉超低温保存前后与氧化应激和细胞凋亡相关的指标进行测定。结果显示,活性氧水平和丙二醛含量在花粉超低温保存前后没有显著变化,而质膜相对透性在超低温保存后显著提高,说明脂质过氧化不是造成细胞膜通透性增强的直接原因。超低温保存后过氧化氢酶活性显著升高,而抗坏血酸含量显著下降,说明超低温保存引起了玉兰花粉细胞内抗氧化防御系统的显著变化,细胞通过氧化/抗氧化系统的自我调节取得了新的平衡,因而使活性氧的水平在保存前后维持了稳定,并未诱导氧化应激的发生。对磷脂酰丝氨酸的外化水平和DNA片段化程度的测定表明,超低温保存并未引起细胞凋亡现象的发生。这可能是维持超低温保存后玉兰花粉高生活力的根本原因。
In order to reveal the physiological mechanism of the cryopreservation of pollen, we used Magnolia pollen as the experimental material to determine the indexes related to oxidative stress and apoptosis before and after the cryopreservation of pollen. The results showed that the levels of reactive oxygen species and malondialdehyde did not change significantly before and after cryopreservation of pollen, but the relative permeability of plasma membrane increased significantly after cryopreservation, indicating that lipid peroxidation is not the direct cause of the enhancement of cell membrane permeability. After cryopreservation, catalase activity increased significantly, while ascorbic acid content decreased significantly, indicating that cryopreservation caused a significant change in the intracellular antioxidant defense system of Magnoliaceae pollen, and a new balance was achieved by self-regulation of the oxidative / antioxidant system , So that the level of active oxygen remained stable before and after storage, did not induce the occurrence of oxidative stress. The determination of phosphatidylserine’s externalization and DNA fragmentation showed that cryopreservation did not cause apoptosis. This may be the fundamental reason for maintaining the vitality of magnolia pollen after cryopreservation.