NITROGENATED FERTILIZATION FAVORS REJUVENATION AND VEGETATIVE PROPAGATION OF Ilex paraguariensis

Abstract

The vegetative growth of plants is dependent on the nutritional conditions of the soil, mainly in relation to the N element. This, favours the formation of cytokines and auxins, essential hormones for sprouting and rooting, respectively. The objective of this search was to evaluate the influence of nitrogen fertilization of Ilex paraguariensis mother trees on epicormic shooting and rooting of its cuttings. Five treatments of fertilization were applied on the mother trees in the study area in the municipality of Urupema, being: control; 250 g of urea (N); 250 g of NPK (5-20-10); 500 g of NPK, and; 250 g of NPK with 30 g of micronutrients. Two evaluations (at 240 and 480 days) were made for: trees with shoots (%), average shoots number and their average length (cm). Shoots were collected at both vegetative evaluations after the application of the experiment (August 2016) and sectioned into cuttings. Cuttings variables were evaluated: survival (%); rooting (%), callus formation (%) and average root number. The best response to epicormic shooting was obtained with 250 g of NPK at 480 days for trees with shoots (>75%), shoot number (4.4) and shoot length (9.9), but considerable results were also obtained at 240 days with urea. For cutting, the best results were also obtained from shoots from 480 days for most treatments (>80% survival and rooting). Nitrogen fertilization is essential for a successful rescue and vegetative propagation by cutting of I. paraguariensis, and longer periods may be able to boost these results.