Effects of some plant growth regulators on leaves content of macronutrients in mango 'Haden'.
Leal F., Sergent E., Anez M.
Author Affiliation: Central University of Venezuela, College of Agriculture, Maracay, Estado Aragua, Venezuela.
: 631-634
Abstract : The effect of some plant growth regulators and chemicals (paclobutrazol (PBZ), ammonium thiosulfate (ATS) and potassium thiosulfate (PTS)) on the macronutrient content of leaves of 9-year-old mango cv. Haden trees at different phenological stages was studied at Maracay, Aragua state, Venezuela (10° 16?N and 67° 36?W, and 450 m a.s.l.), in an area located in the Premountain Dry Forest, characterized by a mean temperature of 25°C; an annual precipitation of 900 mm with a 6 month dry period, from November to April. The treatments were PBZ at 10 ml of active ingredient (a.i.) per tree to all experimental trees but the control, with ATS at 0.5, 1 and 2% or PTS at 1, 2 and 4% applied 60 or 90 days after PBZ treatment. During the experiment, leaves for nutrient analyses were sampled every 2 months. Regular fertilization of the orchard was applied twice before flowering (1.35 kg of urea and 1.4 kg of KCl per tree). There were statistically significant differences in the macronutrient content of leaves depending on the phenological stage. PBZ and thiosulfate treatments had no effect on N, Ca, Mg and S contents of leaves. PBZ treatment reduced the content of K in leaves. Leaf P content tended to be higher following treatment with TPS (2%) applied 90 days after PBZ compared with the PBZ alone treatment.