Department of Botany, University of Aberdeen, St. Machar Drive, Old Aberdeen, Scotland.
Planta. 1968 Dec;81(4):314-32. doi: 10.1007/BF00398019.
Sieve tubes were frozen before being cut from plants and were prepared for electron microscopy by freeze-etching. Structures that may be interpreted as filaments appeared in and near pores through sieve plates. Their presence suggests that filaments seen in sieve-pores prepared chemically may be there normally. Filaments appeared more numerous and compacted in sieve pores between sieve elements that had been pre-treated with glycerol than in those that had merely been frozen. A sieve element treated with glycerol appeared plasmolysed. No evidence was found for membrane-bound transcellular strands through pores in sieve plates even though membrane-bound transvacuolar strands of cytoplasm appeared clearly in nearby parenchyma cells.
在从植物上切割之前，筛管被冷冻，并通过冷冻蚀刻进行电子显微镜准备。在筛板的孔内和附近出现了可能被解释为细丝的结构。它们的存在表明，在化学制备的筛孔中看到的细丝可能通常存在于此。在经过甘油预处理的筛管之间的筛孔中，细丝看起来更多且更密集，而在仅仅冷冻的筛孔中则较少且较松散。用甘油处理的筛管似乎发生了质壁分离。即使在附近的薄壁细胞中清楚地显示了膜结合的胞间液泡间细胞质的跨细胞链，也没有发现穿过筛板孔的膜结合的跨细胞链的证据。
