NITROGENATED FERTILIZATION FAVORS VEGETATIVE RESCUE AND PROPAGATION OF Ilex paraguariensis

Abstract

HIGHLIGHTS 250 g of N or 500 g of NPK rapidly increase epicormic shoots growth in I. paraguariensis. 250 g of NPK have better results for epicormic shoots growth in long therm. The longer the epicormic shoots stays in the mother tree, the better for cutting. I. paraguariensis cuttings are very sensitive to the loss of moisture ABSTRACT The vegetative growth of plants depends on the nutritional conditions of the soil, mainly in relation to the N element. This element favours the formation of cytokines and auxins, essential hormones for sprouting and rooting, respectively. The objective of this study was to evaluate the influence of nitrogen fertilization of Ilex paraguariensis mother trees on epicormic sprouts emission and rooting of its cuttings. Five treatments of fertilization were applied on the mother trees: 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 carried out for: trees with sprouts emission (%), average sprouts number and their average length (cm). Sprouts 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 sprouts emission was obtained with 250 g of NPK at 480 days for trees with sprouts (>75%), sprouts number (4.4) and sprouts length (9.9), but considerable results were also obtained at 240 days with urea. For cuttings, the best results were also obtained from sprouts obtained at 480 days for most treatments (>80% survival and rooting). Nitrogen fertilization is essential for a successful vegetative rescue and propagation by cuttings of I. paraguariensis, and longer periods may be able to boost these results.

Rooting Potential of Ilex Paraguariensis Cuttings of Two Populations of Southern Brazil in Two Rooting Environments

“…However, with the results obtained in this search, it is possible that survival, and therefore all the other variables associated to rooting, are affected by the rooting environments as much as the population of origin, i.e., different correlations between both. The population of UR is from a region known to have the lowest temperatures during winter in Brazil, as well as a lower sunlight incidence and high humidity (MARTINS-RAMOS et al, 2011), and these factors are crucial to determine the species development and adaptation to new environments, especially cuttings of I. paraguariensis (NASCIMENTO et al, 2018(NASCIMENTO et al, , 2019(NASCIMENTO et al, , 2020. Therefore, this population probably obtained a better survival response to MT due to the higher humidity inside the rooting environment itself, promoting better conditions.…”

“…A great number of searches regarding the vegetative improvement of this species have been performed in the last years, mostly taking the vegetative propagation as the main technic for this objective. However, there are still many challenges regarding this technic, mainly aiming to overcome the ontogenetic age (WENDLING et al, 2013;STUEPP et al, 2015;2017a, 2017bNASCIMENTO et al, 2018) as well as regarding the nutrition of the mother tree (NASCIMENTO et al, 2019), the use of growth regulators (BITENCOURT et al, 2009;NAGAOKA et al, 2013;PIMENTEL et al, 2019;NASCIMENTO et al, 2020), testing established clones (BRONDANI et al, 2008;2009;BISOGNIN et al, 2018;PIMENTEL et al, 2019;GAZZANA et al, 2020;VIEIRA et al, 2021) and rooting environments (BRONDANI et al, 2008;2009;NASCIMENTO et al, 2020). In this manner, it is important to take in consideration the possibility of different vegetative propagation potentials of I. paraguariensis from contrasting natural populations, whereas specific conditions such as maturation, for example, may not be a determinant factor.…”