Doctoral Dissertations

Date of Award

6-1965

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Botany

Major Professor

Walter R. Herndon

Committee Members

Gordon E. Hunt, James D. Caponetti, James T. Tanner

Abstract

As an experimental organism, C. zeylanica has been thoroughly investigated in regards to cytology and spermatogenesis (Sundaralingam, li 19U6) and developmental morphology (Sundarallngam, 195ii). Some effects of temperature on growth have been reported (Anderson and Lommasson, 1958), The report of two antheridial types (U-plated or 8-plated) by Griffin and Proctor (1964) has prompted the present investigation.

In this study, plants collected from six counties in Texas (Plate 1) were identified in the field as to antheridial type (Plates 2, 3 and 4). From these collections a detailed examination of several morphological and cytological characters has been made. From unialgal clones established from these same collections, a series of breeding experiments, both within and between the two antheridial types, has been carried out. Included in this study are a comparison and analysis of morphological and cytological variation in field- and laboratory-grown plants. In addition, a historical review of the literature related to the taxonony of C. zeylanicaand a review of some of the paleobotanical work that has been done, especially on putative antheridia from the fossil record, are presented.

The main objective of this investigation has been to determine whether or not morphological and breeding experimental data support the hypothesis that U- and 8-plated populations of C. zeylanicaare separate species and to record in as detailed a manner as possible the variation in both field collections (whose genetic homogeneity cannot be ascertained) and in laboratory-grown clones, A secondary objective has been the inclusion of useful techniques of data gathering, preparation of cytological material (antheridial squashes and oospore wall material) and techniques of culturing of this species. Most of these techniques 5 have been worked out by other investigators or, in some cases, during this study.

This study includes several diverse approaches. Rather than attempt to integrate these into a single paper or to segregate out a literature review section, the entire thesis has been presented as the sum of several individual studies, most of which have been written with their own methods and materials, results, conclusions and (in some cases) discussion segment. Papers touching on each study are reviewed in the appropriate section.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS