ABSCISIC ACID IMPROVES CALCIUM PARTITIONING INTO 'MICRO' TOMATO FRUIT TISSUE

Abscisic acid (ABA) is known to control stomatal conductance and, therefore, transpiration. Research indicates that spray applications of ABA decrease the incidence of the physiological disorder blossom-end rot in tomato fruit tissue. This study investigated the impacts of root tissue ABA applications on tomato leaf and fruit mineral nutrient concentrations in two genotypes of genetically dwarf tomato plants. The purpose of this study was to determine the effects of ABA treatments on partitioning of mineral nutrients in ‘MicroTina’ and ‘MicroGold’ tomato plants. The data indicated that leaf and fruit tissues of both tomato genotypes reacted similarly to ABA treatments. Plants treated with ABA (0.5, 5.0, and 10.0 mg L^-1) had a significant (P ≤ 0.05) increase in tomato fruit tissue calcium (Ca) in both ‘MicroTina’ and ‘MicroGold’ compared to the control treatment (0.0 mg L^-1). In ‘MicroTina’ tomato fruit tissue, Ca ranged from 27.45 µg g^-1 dry weight (DW) to 49.29 µg g^-1 DW, and ‘MicroGold’ tomato fruit tissue Ca ranged from 29.26 µg g^-1 DW to 48.38 µg g^-1 DW. Tomato leaf Ca concentrations were also significantly affected by ABA treatments. Calcium leaf tissue concentrations were significantly lower (P ≤ 0.05) in the the ABA treated plants. In ‘MicroTina’ tomato leaf tissue, Ca ranged from 25,412 µg g^-1 DW to 36280 µg/g DW, and ‘MicroGold’ tomato leaf tissue Ca ranged from 28,160 µg g^-1 DW to 37,825 µg g^-1 DW. Therefore, ABA affected ‘Micro’ tomato Ca partitioning between leaf and fruit tissue.