Physiological and biochemical aspects of tomato seedlings treated with prohexadione-calcium

The objective of this experiment was to study the effects of different concentrations of the plant growth regulators prohexadione-calcium (ProCa) on the growth control of tomato seedlings. The experiment was conducted in the forest seedling nursery of the Faculty of Agronomic Sciences - UNESP, Botucatu Campus-SP. The experimental design was completely randomized, composed of five treatments: 0, 50, 100, 200 and 400 mg of the active ingredient (a.i.) of ProCa, with 4 replicates of 30 seedlings. Treatments were applied with a manual CO2 sprayer when seedlings completed 20 days after sowing. Ten days after applying the treatments, seedling growth analysis, SPAD index, gas exchange, chlorophyll a fluorescence and biochemical analyses were all performed. From the results obtained, the conclusion was that ProCa concentrations inhibited seedling growth without compromising the photosynthetic apparatus.