Growth and chlorophyll production in plant callus tissues grown in vitro

Summary Growth, nutrition and chlorophyll development were studied in chlorophyllous callus tissues isolated from the following edible angiospermous plants: carrot root, crown gall of tomato, endive embryo, leaf petiole and stem of lettuce, leaf petiole of parsley, pea stem and rose stem. Growth patterns of these tissues in vitro were sigmoid. Synthetic media produced less growth, in terms of fresh weight increase, than media containing coconut milk, a highly complex and little understood natural substance. Murashige and Skoog's synthetic medium proved useful for satisfactory growth and chlorophyll production in a number of tissues. Its usefulness was further increased by additional amounts of copper sulphate, potassium nitrate and monobasic ammonium phosphate. Increased levels of iron and magnesium inhibited growth. Incorporation of yeast extract in the tobacco-high-salts-medium produced the highest amount of growth and chlorophyll formation in endive tissue. Presence of exogenous sucrose was essential for the continued good growth of the above callus tissues in vitro. Highest amount of growth took place either in white light or in the dark. Different tissues had different responses to high or low intensities of light. Endive and carrot tissues produced in vitro were palatable to human taste. Endive tissue was particularly good as it also differentiated many small rosettes of leaves, shoots and had a mild aromatic flavor typical of the endive plants grown in nature.