储藏微环境下小麦胚细胞超微结构变化及衰老机制研究

Ultra- structural Changes in Wheat Embryo Cell and Aging Mechanism under Micro- Environment Storage Conditions

采用人工模拟储藏小麦,通过测定小麦胚细胞中的O_2^-、有毒产物MDA的含量、种子活力以及利用透射电镜观察,研究不同储藏微环境(A、B、C、D)下小麦衰老和胚细胞超微结构的变化规律。结果表明:随储藏时间延长和环境温湿度的增加,胚细胞中O_2^-和MDA含量不断增大,种子活力下降,储藏90 d后O_2^-和MDA产生速率都显著高于前期(P<0.05),并且高温高湿D(35℃,85%)条件下三者变化幅度都显著高于低温低湿A(15℃,50%)条件(P<0.05)。电镜观察发现:随储藏温湿度的增高,小麦胚细胞的超微结构损伤也在加剧,主要表现为:细胞形态改变;膜的完整性逐渐丧失;细胞核染色质凝聚,核仁分裂;线粒体数目减少,内外膜破损,出现空泡化等。以此探讨小麦衰老与胚细胞超微结构损伤之间的关系,以期丰富储藏小麦的衰老机制研究。

Artificial storage of wheat has been adopted to measure the variation of wheat aging and embryo cell ultrastructure on different micro-environmental storage conditions（A、B、C、D） was researched by measuring embryo cell O2＋,toxic products of MDA,wheat vitality and observing with transmission electron microscopy.The results showed that on condition the extended storage time and increased ambient temperature and humidity,the content of O2＋ and MDA increased and wheat vitality decreased ; after 90 d storage period,both of O2＋ and MDA generated significantly faster than the previous （P 〈 0.05） ones,and the magnitude in change of the three were all higher at high temperature and humidity （35 ℃,85%） than that of the lower condition （15 ℃,50%） （P 〈 0.05）.Electron microscopy showed that：with the storage temperature and humidity increased,wheat embryo cell ultra-structural damage had intensified,mainly as follows：cell morphology changed; membrane integrity gradually lost; nuclear chromatin condensates,nucleolus split; the number of mitochondria reduced the inside and outside membrane damaged and vacuolization occurred and so on.Here the results can be used to investigate the relationship between the wheat aging and embryo cell ultrastructure damage,expecting to enrich the wheat aging mechanism.