Department of Horticulture, Kasetsart University, Kamphaeng Saen campus, Nakhon Pathom 73140, Thailand.
Protoplasma. 2010 May;241(1-4):51-61. doi: 10.1007/s00709-010-0105-0. Epub 2010 Feb 17.
Using transmission electron microscopy, we investigated the ultrastructure of mitochondria in petal mesophyll cells of the orchid Dendrobium cv. Lucky Duan, from the time of floral opening to visible petal senescence. Cells close to the vascular bundle contained many mitochondria, some of which showed internal degeneration. This inner mitochondrial breakdown was accompanied by an eightfold increase in mitochondrial volume. Small electron-dense granules (approximately 0.04 mum in diameter) at the periphery of the mitochondrial matrix remained. These granules were used as an indicator of still later stages of mitochondrial development in these cells. The apparent final stage of mitochondrial degeneration was a single-membrane-bound vesicle, resembling a vacuole. No evidence was found for the idea that mitochondria became transferred (intact or degenerated) into a lytic vacuole. Taken together, the data suggest the hypotheses that (a) mitochondria in cells close to the vascular bundle in petals of open Dendrobium cv. Lucky Duan flowers undergo large-scale internal degeneration and that (b) such degenerating mitochondria form vacuole-like vesicles.
利用透射电子显微镜，我们研究了从兰花幸运牡丹花朵开放到可见花瓣衰老期间，花瓣叶肉细胞中线粒体的超微结构。靠近维管束的细胞含有许多线粒体，其中一些显示内部退化。这种线粒体内部的崩溃伴随着线粒体体积增加八倍。线粒体基质边缘的小电子致密颗粒（直径约 0.04 微米）仍然存在。这些颗粒被用作这些细胞中线粒体发育后期阶段的指标。线粒体退化的明显终末阶段是单个膜结合的囊泡，类似于液泡。没有证据表明线粒体被转移（完整或退化）到溶酶体中。综合来看，这些数据表明了以下假设：（a）在开放的幸运牡丹花朵花瓣中靠近维管束的细胞中线粒体经历大规模的内部退化，以及（b）这种退化的线粒体形成类似液泡的囊泡。
