Iron indices and micronutrients in deciduous fruit trees

Abstract

Perennial deciduous plants were studied during their vegetative cycles. Leaves were sampled regularly every 15 days throughout this period in order to determine total and soluble iron (Fe) indices, physiological balances, and micronutrient levels. Analysis of variance and coefficients of variation were high for Fe indices and micronutrients between samples. The values of interaction between variables were not high. The optimium value of total Fe index ranged from 0.72–0.74 in almond to 1.11–1.14 in pomegranate. Optimum values for soluble Fe index ranged from 0.77–0.83 in almond to 1.18–1.29 in pear. Similar ranges were observed for soluble and total micronutrients and ternary groups. The evolution of the physiological ternary groups demonstrates ionic imbalances in apple in total Fe and manganese (Mn) as a result of excess levels of total zinc (Zn) during the final phase of fruit development. During this phase, total and soluble Fe and Mn also show significant interactions in persimmon. In apple, the Fe‐Mn‐copper (Cu) balance was markedly altered during fruit ripening and foliar senescence. This pattern of evolution of physiological indices is expected in perennial plants, with a sharp decline during fruit ripening in all species studied: almond (Amygdalus communis L.), apple (Malus communis Poir.), pear (Pirus communis L.), pomegranate (Punica granatum L.), hazelnut (Cotylus avellana L.), and persimmon (Diospyros kaki L.).