Relation of Nutrient Salt Concentration to Growth of the Tomato and to the Incidence of Blossom-End Rot of the Fruit

Abstract

IntroductionThe control of the nutrient salt concentration of the solution bathing plant roots is a factor of importance in plant growth whether in artificial culture or in soil. When essential salts are present in very low concentrations, growth may be limited by a deficiency of one or more of the elements necessary in plant metabolism. When salt concentrations are high, growth is dependent upon factors other than mere quantitative nutrient supply. One of these factors is the osmotic concentration of the solution which, in turn, affects the water, relations within the plant.In the tomato plant, a serious disturbance of the normally existing water relations has been assigned as the cause of the physiological disease of the fruit known as blossom-end rot. This disease consists of the development at the stylar end of the fruit of a spot having a slight, watery discoloration of the tissue which increases in size and gradually turns from brown to black. It is accompanied by a shrinkage of the affected part of the fruit. The symptoms of this disease are known, its occurrence has been frequently described, and the serious loss which it causes in some seasons is well recognized (1,3,15,28,29,35).Although the development of blossom-end rot is evidently concerned with the adequacy of the water supply of the affected tissues of the fruit, yet many other factors than the concentration of the nutrient solution have been indirectly associated with the incidence of this fruit disorder in the garden, field, and greenhouse. Low soil moisture has been the factor most often associated with the development of blossom-end rot of the tomato (3,29,35). Various other cultural or environmental factors have likewise been associated with the incidence of this disease as: over-watering the soil (15), and the attendant lack of gaseous exchange in the soil following heavy watering (28); the staking of tomato plants (29,30); the use of unbalanced fertilizers high in potassium and ammonium salts (1, 35); and the transfer of tomato plants from a shaded to a non-shaded greenhouse (3). Vigorously vegetative plants have been found to be more generally affected with blossomend rot than plants grown less vigorously (3, 15). On the other hand,

Effect of Nutrient Ratio and Concentration on Growth and Composition of Tomato Plants and on the Occurence of Blossom-End Rot of the Fruit

“…The occurrence of blossom-end rot in the concentration series was similar to the results of ROBBINS (2), except that the percentages in this experiment were much lower. It must be remembered that the plants in this experiment were grown in the open in a climate with a rather high humidity and relatively cool days.…”

“…This would be more nearly like the application of fertilizer under field conditions. Blossom-end rot has recently been reviewed by ROBBINS (2) with many references given on the subject. In most cases a disturbance of the normal water relations has been assigned as a cause of the physiological disease.…”

Some Effects of Sodium Salts on the Growth of the Tomato

“…As CHANDLER (1) and ROBBINS (11) have pointed out, in most cases the osmotic concentration of the juice of vegetative parts tends to exceed that of the fruit. At control, low, and intermediate levels of sodium concentration where the osmotic concenitration of the substrate ranged from 1.6 to 4.6 atm.…”

“…ROBBINS (11) concentration of other cations in the juice. In the A series (high sulphate) with increasing increments of sodium salts, the reduction in the amounts of Ca, Mg, and K was progressive.…”

Calcium and its relationship to blossom‐end rot in tomato

“…The literature up to 1937 was examined by Robbins 23 who added experimental results of his own; after emphasizing the close depeti dence of the plant upon an abundant water supply for the rapid growth of tissues and for the development of fruit, he presented data showing that a result of lack of this readily available water supply is the development of the blossom end rot of the fruit; this occurred when nutrient solutions of high salt concentrations were employed: 80% of the fruits on plants grown with solutions with concentrations corresponding to 1.7 and 3.1. atmospheres developed the physiological disorder. The main conclusion was: any factor which either seriously restricts the rate of absorption or greatly increases the rate of transpiration of water by the plant will increase the probability of the incidence and development of blossom-end rot of the fruit.…”