A SHOOT AND LEAF GROWTH MODEL OF APPLE TREES AT DIFFERENT LEVELS OF ZINC NUTRITION

Zinc deficiency results in a low growth rate, small leaves and decreased shoot growth and photosynthetic rates, which influence the dry matter accumulation, ultimately reducing the apple yield and quality. Thus, it is essential to study the dynamic model of apple tree growth in orchards under different zinc levels in an effort to improve the nutrient level and management of apple trees. We investigated a sand culture experiment using young Fuji (Malus domestica ‘Fuji’) apple trees under 5 zinc application levels (0, 5, 15, 45 and 135 μmol L^-1), with the goal of building a two-level model for the shoot and leaf growth of apple trees under different zinc levels. The shoot and leaf growth of the young apple trees showed a logistic model response to the sampling date, and the parameters of the logistic model were determined by the zinc level. The results support some of the hypotheses with respect to dry matter modeling under zinc stress in apple trees and provide a foundation for decisions regarding apple tree management.