Application of paclobutrazol and GA3 to adult peach trees: Effects on nutritional status and photosynthetic pigments

Soil applications of 1 or 2 g paclobutrazol (Pbz) and foliar sprays of 1000 mg L^-1 GA₃ to adult peach trees Prunus persica (L.) Batsch] had opposite effects: vegetative growth was inhibited by paclobutrazol and promoted by GA₃, whereas mean fruit yield was greater in Pbz-treated trees and less in GA₃-sprayed trees. Compared to controls, differences in the concentration of different mineral nutrients occurred in leaves collected shortly after fruit harvest: in Pbz-treated trees, the concentration of N and K significantly decreased, whereas that of Mg and Mn increased. Leaves of trees sprayed with GA₃ had a significantly lower concentration of N and Ca and Mn, and a slightly greater concentration of K. In spite of these changes, element concentrations were within accepted ranges and therefore the nutritional status of peach trees did not change with the application of both growth regulators. Pbz did not alter the concentrations of chlorophylls, whereas GA₃ significantly reduced the concentrations of chlorophylls a and b. Neoxanthin, violaxanthin, antheraxanthin, lutein, zeaxanthin, and ß-carotene concentrations were unaffected by all treatments.Mention of trademark, warranty, proprietary product, or vendor does not constitute a guarantee by the C.S.I.C. (Ministry of Education, Spain) and does not imply its approval to the exclusion of other products or vendors that may be suitable.