低氧对小麦根端分生细胞核仁结构和功能的影响

Hypoxia Can Damage Nucleolar Structure and Inhibit Its Function on Root-tip Meristematic Cells of Common Wheat

为了探讨低氧对小麦根端分生细胞核仁结构和功能的影响,本实验以普通小麦为材料,用低氧水处理其根尖,按常规细胞制片、银染、电镜观察、间接免疫荧光染色和半定量PCR分析等手段开展研究。观察发现:(1)低氧水处理后小麦核仁结构发生膨胀、突出、进而凝集、内部出现空泡、细微结构消失、核仁通道结构异常、甚至解体等一系列变异现象。(2)间接免疫荧光染色技术观察看到,低氧水处理后小麦核仁内的核磷蛋白B23向核质甚至胞质扩散。(3)半定量PCR分析显示,低氧处理后rRNA基因的表达量较对照明显降低,而且C23的表达信号几乎检测不到,表明核糖体RNA和核仁蛋白C23基因的表达均显著下调,低氧严重抑制它们的转录。研究证明,低氧除了对小麦根端分生细胞核仁结构有破坏作用外,还严重抑制核仁的功能。

In this test, common wheat root tips were treated with hypoxia water to explore the effects of hy- poxia on nucleolar structure and function of root-tip meristematic ceils of common wheat using serials of techniques, such as conventional cell preparation, silver staining, electron microscopic observation, indirect immunofluorescence staining and RT-PCR analysis. It was observed that, after hypoxia water treatment, （1） the nucleoli in the meristematic cells became swell, protruded and agglutinated;some inner vesicular and abnormal nucleolar channels appeared;the fine structures of the nucleolus were disappeared and even more, the nucleolus was segregated,etc. （2）Nucleophosmin B23 shuttled from nucleoli to nucleoplasm, even to cytoplasm revealed by indirect immunofluorescence staining techniques. （3）RT-PCR analysis indicted that the expression level of rRNA gene was lower obviously than that of control and the expression signal of C23 was undetectable. It means that the expressions of both ribosomal RNA and C23 genes were down-reg- ulated significantly. Our results demonstrate that hypoxia treatment can not only damage nucleolar struc- ture but inhibit its function.