Influence of Auxin Bioregulators on Physiological Changes and Shelf-Life of Tomatoes
Tomato (Solanum lycopersicon) is one of the most popular and extensively consumed vegetable crops worldwide. Their highly perishable nature poses great limitation to their marketability over long distances. We have earlier demonstrated that the 100 mg·L-1 concentration of the bioregulators Indoleacetic acid (IAA), indole butyric acid (IBA) and naphthalene acetic acid (NAA) is suitable for tomato growth under field conditions. We have also reported the effects of these bioregulators on tomato fruit yield and postharvest quality. In this study, the shelf - life and associated physiological changes of fruits of five bioregulator - treated tomato genotypes in practical conditions of storage time and temperature were investigated. Seeds of the tomato genotypes namely NHLy 11, NHLy 12, NHLy 13, NHLy 15 and NHLy 16 were subjected to treatments with 100 mg·L-1 concentrations of the bioregulators IAA, IBA, NAA and distilled water (control) before planting. The fruits were harvested at the orange - red ripe stage. Sensory and visual fruit changes were determined and deterioration level measured during storage trials for up to ten days in order to evaluate their quality. The results revealed that the bioregulator - treated tomato genotypes generally exhibited better storage features than those of controls, with the NAA - treated NHLy 12 genotype having the highest storability index of 6.00 after ten days of storage. The present findings show that treating tomatoes with bioregulators, especially the ones used in this work improves their storage at ambient conditions.
Bioregulators Favourably Affect the Levels of Vitamins and Sugars in Tomato Fruit Tissues
This study aimed to examine the influence of exogenous application of the bioregulators indole acetic acid (IAA), indole butyric acid (IBA) and naphthalene acetic acid (NAA) on the vitamin and sugar content of tomatoes. Harvested fruits of the treated tomato genotypes, namely NHLy 11, NHLy 12, NHLy 13, NHLy 15 and NHLy 16, were analysed for these parameters. Spectrophotometric analysis results showed that IAA significantly increased (p<0.05) the concentrations of β-carotene, vitamin A and ascorbate in all the tested genotypes, with the highest values of 707.84 μg·100 g-1 fwb, 118.21 μg·100 g-1 RE and 20.36 μg·100 g-1 fwb, respectively, in the NHLy16 genotype. The total sugar content was not significantly affected by the treatments. It is proposed that exogenous application of these bioregulators to plant foods such as tomatoes can improve their phytonutrient concentrations, promoting better public health.