THE INFLUENCE OF BORON ON THE CHEMICAL COMPOSITION AND GROWTH OF THE TOMATO PLANT

Open Access
Publisher Website
Google Scholar
Abstract
The conclusions drawn from a series of water culture experiments carried out at the Universities of California and Maryland with 2 varieties of tomato, Santa Clara Canner and Marglobe, may be summarized as follows: Boron, in a concentration of approximately 0.5 ppm., was found necessary for the normal growth and development of the tomato plants. Tomato plants grown in B-deficient solutions show 4 distinct types of injury; (a) death of the terminal growing point of stem; (b) breaking down of the conducting tissues in the stem; (c) a characteristic brittleness of stem and petiole; and (d) roots of extremely poor growth and of a brownish unhealthy color. As a result of broken down conducting tissues the B-deficient plants differed markedly from normal plants in their chemical composition. Total sugars and starch were more abundant in the leaves and stems of the B-deficient plants while a greater amount of benzene-soluble matter was found in the leaves of the normal plants and in the stems of the B-deficient plants. Evidence is presented which shows the possibility of a quantitative relationship existing between the amount of growth and the amount of B present in the nutrient media. A concentration of 5.5 ppm. B in the nutrient solution was toxic to the plants. Symptoms of boron toxicity are quite different from deficiency injuries.