Efeito de diferentes concentrações de óxido de lantânio no crescimento e desenvolvimento do capsicum annuum

Abstract

The importance of Rare Earth Elements (REEs) has been increasing considerably in the high-tech industry as raw materials for various products such as catalyst, cathode ray tubes and luminescent materials due to their characteristics: low hardness, highly magnetizable, ductile, malleable and good conductors of heat and electricity. Furthermore, in the agronomic and zootechnical spheres, soil fertilization practices or supplementing animals diets with REEs are becoming quite conditional and offer suggestive and stimulating challenges worldwide in terms of achieving better crop yields or in livestock breeding. Bell pepper (Capsicum annuum L.) is an angiosperm that belongs to the Magnoliopsida class, of the Solanaceae A. Juss family and of the Capsicum genus, and it is one of the ten most economically important vegetables in the Brazilian market. Chemical and physical characteristics of the soil are quite demanding aspects of this plant, with good response and greater productivity to the combination of organic and mineral fertilization. This study aims to evaluate the effect of lanthanum oxide on the growth of Capsicum annuum L. For exposure analysis, germination time, stem and leaf length were analyzed, general plant characteristics were evaluated and dry weights of seedlings after thinning were quantified for peppers exposed to five different concentrations of lanthanum oxide (1, 15, 60, 240 and 480 ppm). For germination rates, it was shown that in 2 weeks after planting, the control group and 1 ppm had the best germination rates (2 germinated seeds), with the 15 ppm group having the worst performance (1 germinated seed at the end of the 3rd week) and at the end of 6 weeks, the 240 ppm group was statistically different from the control group. When evaluating the growth indices (number and size of leaves and stem growth), it was not possible to observe a significant visual difference between the groups in 32 weeks of exposure, however, in relation to the stem, a statistical difference was observed between the 1 ppm and 240 ppm groups in the 17th week with p < 0.04. In relation to the leaves, a statistical difference was observed between the control and 240 ppm groups with p < 0.0001 and 0.0007 (respectively for quantity and length of the largest leaf). Even so, a slight tendency of increase in the production of dry matter of the aerial part of the plants was observed, for the lanthanum oxide concentrations of 15 ppm, 60 ppm, 240 ppm and 480 ppm (0.095; 0.095; 0.082; 0.069 g respectively) when compared to the control (0.058 g). It is concluded that exposure to lanthanum oxide did not present a statistically significant influence on the growth of peppers in 32 weeks, but further studies should be carried out to better understand the effect of REEs on the development of the reproductive structure and fruits to better evaluate the use of these minerals as fertilizers in peppers.