Comunicação térmica em sementes de Moringa oleifera Lam.: implicação para a sua utilização em programas de recuperação de áreas degradadas

Abstract

The species Moringa oleifera Lam., belonging to the Moringaceae family, has adapted well in regions of the northeast, mainly in the States of Maranhão, Piauí, Ceará and Pernambuco, and is cultivated in the semi-arid region due to its tolerance to drought and adaptation to different types of soils and in other regions of the country, standing out in popular medicine, for its healing therapeutic properties, forage, condiment, for the cosmetics industry, melliferous, source of energy, as well as in water purification treatment through the coagulant solution made from of seeds. Based on the above, the objective of the present work was to evaluate ecological and applied aspects of temperature in the germination of M. oleifera seeds. The experiment was conducted at the Laboratory of Fitotecnia, Campus de Engenharias e Ciências Agrárias (CECA), using six lots of M. oleifera seeds from the experimental area of CECA, harvested in the 2020 and 2021 harvests. The isothermal incubation was carried out under constant temperatures of 5, 10, 15, 20, 25, 30, 35 and 40 oC. The germinated seeds were counted daily, from the installation of the germination test, during ten days. To explain the variations in germination speed over the entire thermal interval, a graph of coordinates y = –RlnV (V = experimental values of speed) and x = A(1/T) x 105, with R = 1.987 Kcal.mol–1 and T in Kelvin, based on the activated complex model. The net change in germination activation energy (enthalpy) was calculated from the Arrhenius equation. The optimal temperature for M. oleifera seeds was found in the range of 30 oC ≤ T oC ≤ 35 oC, since in this temperature range a greater number of germinated seeds would be obtained and with a higher Germination Speed Index. It was found that M. oleifera seeds subjected to temperatures in the optimal range of 25 oC ≤ T oC ≤ 35 oC, showed greater germination uniformity. M. oleifera seeds germinate in the range of 10 oC ≤ T oC ≤ 40 oC. The optimum temperature for germination of M. oleifera seeds is 26 oC.