向日葵幼叶及其培养的愈伤组织细胞的超微结构研究

ULTRASTRUCTURAL STUDIES ON CELLS OF YOUNG LEAF AND ITS CULTURED CALLUS IN SUNFLOWER

通过超微结构的观察,向日葵幼叶及其经培养后10天的愈伤组织细胞之间有明显区别。叶肉细胞的细胞质、细胞器及核的结构和发育都比较完整。当外植体组织发生变化和愈伤组织形成时,观察到线粒体相互连接成链状围绕在叶绿体周围,而叶绿体有的围绕在核的周围;线粒体的嵴和基质,叶绿体的基粒和片层结构常发生退化或解体,细胞质稀薄,核糖体和胞质凝成线状或网状,微体和高尔基体消失,液泡化程度高并含有较多的次生物质;而细胞核在后期才发生明显变化,轮廓不够清晰。

Through electron microscopy, it was observed that obvious differences were existed in ultrastructure between cells of young leaf and its callus after ten day's culture in sunflower.Obvious changes were observed in ultrastructure during cell changes and callus formation. There was thinner cytoplasm. Granum lamella of plastid degenerated, so did mitochondria cristae and matrix Mitochondria were joined in chains with each other and distributed around the chloroplasts which also around the periphery of the nucleus, vacuoles became highly enlarged and contained some substances. Groups of membrane-enclosed vesicles were found in some changing cells, cohedion of ribosomes and cytoplasms formed line-or net-shaped structures, The microbodies and dictyosomes disappeared in cells.The nuclei of cells at earlier stage of change did not evidently changed, However, at later stage of callus development, some obvious changes also occurred and the contour of nuclei became unclear.