The aim of this project has been to gain experience in electron microscopy and to investigate selected problems of ultrastructure in root tips using techniques of thin sectioning and freeze-etching. The work was conducted while employed as a full time University Lecturer. Studies began in 1963 and were continued in 1964 during visits to the Physics and Engineering Laboratory (P.E.L.) D.S.I.R., Lower Hutt. Towards the end of 1965 practical work began at Canterbury following the acquisition of

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... ipment and improved facilities. In 1968 a further visit was made to P.E.L. to use the recently installed freeze-etch equipment. In the absence of experienced ultrastructural plant oytologists for guidance throughout most of the study, one of the principal tasks has been the selection of material and problems amenable for investigation. Exploratory work was carried out on the fine structure of meristem and differentiating root cap cells (Fineran, 1966 – included here as an appendix). From this study a more detailed investigation developed on the ultrastructure of vacuoles. The final results and discussions of this work on the vacuole and the necessary preliminary experiments on the preparation of root tips for freeze-etching form the basis of this dissertation. Each chapter represents a unified topic within the framework of the project. The literature relevant to each topic is reviewed in the chapter concerned. An integral part of the project involved the establishment of an electron microscope laboratory in the Botany Department of this University.