胡萝卜和梧桐悬浮培养细胞中的质膜“玫瑰花结”

Plasma membrane "rosettes" in carrot and sycamore suspension culture cells.

作者信息

Chapman R L, Staehelin L A

出版信息

J Ultrastruct Res. 1985 Oct-Nov;93(1-2):87-91. doi: 10.1016/0889-1605(85)90088-6.

Abstract

Suspension culture cells of carrot, Daucus carota L., and sycamore, Acer pseudoplatanus L., were freeze-fractured after ultrarapid freezing without fixation or cryoprotection in a propane-jet freezer. Infrequently, rosettes (ca. 24 nm diameter) of six (occasionally five) subunits (ca. 8 nm diameter) were observed in P-face views of the plasma membrane of both taxa. When present, rosette density was approximately 1/micron 2. Generally, rosettes were less frequently seen on plasma membranes exhibiting numerous vesicle fusion figures. Due to the high quality of the freezing, cellulose microfibril impressions were rarely seen on either PF or EF views of the plasma membrane, thus precluding correlations between microfibrils on the one hand and rosettes (and terminal globules) on the other. The presence of rosettes in suspension culture cells of these two species supports the putative role of rosettes in cellulose biosynthesis in higher plants.

摘要

胡萝卜（Daucus carota L.）和悬铃木（Acer pseudoplatanus L.）的悬浮培养细胞在丙烷喷射式冷冻机中进行超快速冷冻后，未经过固定或冷冻保护处理就进行了冷冻断裂。在这两个分类群的质膜P面视图中，偶尔会观察到由六个（偶尔五个）亚基（直径约8纳米）组成的玫瑰花结（直径约24纳米）。当存在时，玫瑰花结密度约为每平方微米1个。一般来说，在呈现大量囊泡融合图像的质膜上，玫瑰花结较少见。由于冷冻质量高，在质膜的PF或EF视图上很少能看到纤维素微纤丝印记，因此无法建立微纤丝与玫瑰花结（和末端小球）之间的相关性。这两个物种悬浮培养细胞中玫瑰花结的存在支持了玫瑰花结在高等植物纤维素生物合成中假定的作用。