Acúmulo de nutrientes e carboidratos em populações da espécie Myrsine cariacea

• Autor(a) principal: Leite, Kelvin de Jesus
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/13254
• topic: Agronomia; Dimorfismo sexual; Dioicia; Plasticidade fenotípica; Altitude; Sexual dimorphism; Dioecious; Phenotypic plasticity; subject.br-rjbn

In dioecious species, female and male individuals may present differences in some ecophysiological characteristics. The sexual dimorphism in characteristics related to the absorption and use of resources is expressed mainly during the reproductive period, because the investments of the male individuals are limited to the flowering, whereas the feminine, in addition to producing the flowers, had to invest a great quantity of the resources available for fruit production. However, variations in environmental conditions, as occurs along an altitude gradient, affect the ecophysiological performance of plants, and may modify the differential demand of resources between the sexes and, consequently, the accumulation of nutrients and carbohydrates. The objective of this work was to examine the differential accumulation of nutrients and carbohydrates in individuals of eight populations of the Myrsine coriacea dioecious species, located along an altitude gradient in the Atlantic Forest. At the end of the fruiting period, leaf samples were collected from twelve individuals (six female and six male) from each of the eight populations analyzed. Analyzes were performed to determine the concentration of nutrients and non-structural carbohydrates in leaf tissue. Soil samples were collected in the canopy projection of each individual to study the relationship between soil chemical conditions and nutrient accumulation in leaves. The accumulation of carbohydrates and nutrients was similar between the sexes, with significant differences only between the populations. The population located at the highest altitude (1774 m altitude) had a higher accumulation of soluble carbohydrates (glucose and fructose) and less accumulation of starch, potassium and boron in relation to other populations. A negative relationship was observed between altitude and nitrogen, potassium and boron leaf accumulation; for the accumulation of iron and calcium the relation was positive. The availability of nutrients in the soil was significantly different between the sexes, but this response is dependent on the conditions of each population. The concentrations of potassium, calcium and magnesium in the leaves were associated with the availability of these macronutrients in the soil. However, the availability of phosphorus in the soil was not associated with the concentration of this macronutrient in the foliar tissues. It should be noted that the differences in soil chemical conditions verified between the sexes were not accompanied by significant variations in the accumulation of nutrients in the leaves. Thus, our findings indicate that male and female plants of M. coriacea must present variations in the mechanisms of production / absorption, assimilation and / or allocation of carbohydrates and nutrients, as a way of supplying differential reproduction costs, maintaining the same carbohydrate concentration and nutrients in leaf tissues.