Biology Department, Dalhousie University, B3H 4J1, Halifax, N.S., Canada.
Planta. 1978 Jan;140(1):53-8. doi: 10.1007/BF00389379.
Freeze-etch observations of protoplasts isolated from tobacco (Nicotiana tabacum L.) mesophyll tissue and tomato (Lycopersicum esculentum Mill.) fruit locule tissue are described which clarify earlier observations (Burgess, J., Fleming, E.N., Planta 131, 173-178, 1976; Planta 133, 267-273, 1977), obtained using scanning electron microscopy. of "fibres" associated with "projections" from these cell surfaces. It is demonstrated (1) that the "fibres" consist of bundles of small numbers of microfibrils which have become artifactually thickened by the deposition of coating materials, and (2) that the apparent association between "fibres" and "projections" results from microfibrils being lifted preferentially from protoplast surfaces in regions rich in "projections" (plasmalemmasomes). With the higher resolution available using freeze-etching it can be demonstrated that microfibril deposition does not occur in discontinuous zones on these protoplast surfaces. Globules associated with microfibril termini in radish (Raphanus sativus L.) roots are illustrated and it is proposed that turgor pressure differences between isolated protoplasts and intact tissue may account for the absence of similar globules from isolated protoplast surfaces.
描述了从烟草（Nicotiana tabacum L.）叶肉组织和番茄（Lycopersicum esculentum Mill.）果实腔组织分离的原生质体的冷冻蚀刻观察结果，这些结果澄清了早期使用扫描电子显微镜观察到的与这些细胞表面“突起”相关的“纤维”的观察结果。（1）“纤维”由少量微原纤维束组成，这些微原纤维由于涂层材料的沉积而人为地变厚；（2）“纤维”和“突起”之间的明显关联是由于微原纤维优先从富含“突起”（质膜小体）的原生质体表面抬起。使用冷冻蚀刻可以获得更高的分辨率，可以证明微原纤维沉积不会在这些原生质体表面的不连续区域发生。本文还展示了与萝卜（Raphanus sativus L.）根中微原纤维末端相关的小球体，并提出了分离的原生质体和完整组织之间的膨压差异可能是导致分离的原生质体表面没有类似小球体的原因。
