Characterisation of programmed cell death during aerenchyma formation induced by ethylene or hypoxia in roots of maize (Zea mays L.)
Characterisation of programmed cell death during aerenchyma formation induced by ethylene or hypoxia in roots of maize (Zea mays L.)
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DOI：
10.1007/s004250000381
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发表时间：
2001-01-01
期刊：
影响因子：
4.3
通讯作者：
Evans, DE
中科院分区：
文献类型：
--
作者：
Gunawardena, AHLAN;Pearce, DM;Evans, DE
通气组织是一种以突出的细胞间隙为特征的组织类型，它通过促进根和空气环境之间的气体扩散来增强某些植物的耐洪能力。玉米根系中的通气组织是由部分皮层细胞的塌陷和死亡形成的，这一过程可以通过缺氧或乙烯处理来促进。在3%氧、1 μ l（-1）乙烯和21%氧（对照）条件下水培的玉米根通过光镜和电镜分析，利用原位末端脱氧核苷酸转移酶介导的dUTP镍端标记（TUNEL）提示核小体间DNA切割。然而，电镜下可检测到的染色质凝聚发生在细胞质变化之前，包括质膜内翻和囊泡的形成，而在哺乳动物细胞凋亡中，染色质凝聚是第一个可检测到的事件。随后观察到细胞凝聚、染色质凝聚和被类似凋亡小体的膜包围的完整细胞器的存在。所有这些过程都在细胞壁明显降解前完成。因此，缺氧或乙烯引发的通气组织形成似乎是一种程序性细胞死亡形式，其特征部分类似于动物细胞的凋亡和细胞质细胞死亡。
Aerenchyma is a tissue type characterised by prominent intercellular spaces which enhance flooding tolerance in some plant species by facilitating gas diffusion between roots and the aerial environment. Aerenchyma in maize roots forms by collapse and death of some of the cortical cells in a process that can be promoted by imposing oxygen shortage or by ethylene treatment. Maize roots grown hydroponically in 3% oxygen, 1 muL l(-1) ethylene or 21% oxygen (control) were analysed by a combination of light and electron microscopy, Use of in-situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) suggested internucleosomal cleavage of DNA. However, chromatin condensation detectable by electron microscopy was preceded by cytoplasmic changes including plasma membrane invagination and the formation of vesicles, in contrast to mammalian apoptosis in which chromatin condensation is the first detectable event. Later, cellular condensation, condensation of chromatin and the presence of intact organelles surrounded by membrane resembling apoptotic bodies were observed. All these events were complete before cell wall degradation was apparent. Therefore, aerenchyma formation initiated by hypoxia or ethylene appears to be a form of programmed cell death that shows characteristics in part resembling both apoptosis and cytoplasmic cell death in animal cells.