Effect of Mineral Nutrition on the Ascorbic-Acid Content of the Tomato

Four experiments were carried out to measure the influence of environmental conditions on the ascorbic-acid content of Bonny Best tomatoes. Two of them were designed to test the influence of macronutrient supply and the others measured the influence of climatic environmental factors. 2. In sand cultures, growth and fruitfulness could be correlated with minor variations in nutrient composition. 3. Gross appearances of plants grown in eighty-seven different solutions are discussed and quantitative data presented for growth and fruitfulness. These data are reduced and analyzed by statistical methods. 4. In general, variations in calcium and nitrate in the nutrient medium produced greater differences in growth and fruitfulness of plants over wider ranges of concentrations than were obvious with the other elements. Interactions of the effects of various elements were noted. 5. Ascorbic-acid content of the fruit was significantly higher in some sulphate-deficient treatments and significantly lower in potassium and phosphate deficiencies than average values. With these exceptions, no demonstrable effect of mineral nutrient supply on ascorbic acid was observed. 6. Plants grown during the fall and winter produced fruit with approximately one-half as much ascorbic acid as was produced by comparable plants during the summer. 7. The location where the plants were grown had an effect upon the ascorbic-acid content of the fruit. These effects could not be correlated with differences between soils at the several locations and were apparently associated with differences in the environment of the top of the plant. Significant positional effects on ascorbic-acid content, even in a relatively small trial plot, were observed. 8. Plants grown in sand culture supplied with a balanced nutrient solution produced fruit as high as or higher in ascorbic-acid content than that obtained through the use of a good soil. 9. Several other observations are included relative to the effects of variations in mineral nutrition on growth and fruitfulness and the influence of environment upon ascorbic-acid content. 10. A discussion of the possible practical significance of the results obtained is included.