Effects of boron on nutrient partitioning, Ca movement, and fruit quality of tomatoes

Abstract

This study was aimed to investigate the effects of boron on Ca movement, yield, and quality of tomatoes. A soilless culture experiment with three levels of B (0, 25, and 50 µM) and three concentrations of Ca (2, 4, and 8 mM) was carried out to grow tomatoes. The results showed that although the application of boron to the sample was more effective in the vegetative growth and the fruit induction, resulting in higher numbers of fruit, the addition of Ca could more effectively enhance the weight and quality of the fruit. With B application, Ca-symplast increased, while pectin methylesterase activity decreased, resulting in less Blossom End Rot indices and more fruit firmness. The Ca-transfer index from apoplast to symplast slightly increased with the B application. Overall, in terms of fruit quality and quantity, the best result was seen in higher Ca application as well as higher B concentrations. Although exogenous boron could help Ca absorption in the root and the shoot, it lowered the Ca transfer from xylem to apoplast and symplast, from shoot to fruit, and from the proximal to distal end of the fruit. Nevertheless, loading 4 and 8 mM of Ca seems to provide enough calcium reserves in fruits to have better quality and yield.