Some observations made on the growth of Oedogonium sp

The growth of an unidentified species of the green fresh water alga. oe dogonium lias been investigated under natural conditions and under varying conditions of culture. The material used in the investigation was collected from a pond in the Botany Garden, Royal Holloway College. Cultures were established in the laboratory in a number of different solutions of which soil extract solution proved to be the most satisfactory. Observations were made on filaments of different ages both in the material grown in the pond and in the material grown in culture, and records were made of:- 1. The variation in the cell size of the filaments by means of measurements of cell length; 2. The distribution and the size of the groups of caps which were found in the filaments. Attempts were made to discover whether the addition of growth substances to the culture medium affected the growth of the filaments. The substances used singly in the various cultures were as follows 1. Yeast extract 2. Thiamine 3. Indole-3-acetic acid 4. Arnaphthalene-acetic acid. Records similar to those made on the filaments from the pond and from soil extract solution were repeated on /these these cultures. Attempts were also made to investigate the effect of these substances on the rate of cell division in the filaments. Cultures were set up with the addition of colchicine to find the effect of this substance on cell division in Oedogonium sp. An attempt has been made to use these results to interpret the general pattern of grov/th and development in the species of Oedogonium used in this investigation.