Relação entre características funcionais de folhas e seu conteúdo de nitrogênio e fósforo de onze espécies arbóreas tropicais

Abstract

The survival and growth of tree species can be strongly related to morphological, physiological and phenological characteristics, since they determine their ability to acquire, use and conserve resources and are usually referred to as functional traits. The development of effective forest restoration strategies depends on an understanding of the relationships between functional traits and the probability of survival and growth of individuals. Functional leaf characteristics such as leaf area, specific leaf area and leaf dry matter content are related to the ability to obtain resources and the strategies for using resources by plant species and can be correlated with each other. This study experimentally evaluated the relationships between leaf characteristics and the relationship between these characteristics and the concentration of nitrogen and phosphorus in the leaves of eleven tree species that are commonly used in riparian forest restoration projects. Seedlings of these eleven species were planted in a degraded area, five species considered pioneer and six non-pioneer. The leaf area (LA), specific leaf area (SLA) and leaf dry matter content (LDMC) were measured from five individuals of each species. Leaf concentrations of nitrogen, phosphorus, calcium, magnesium, potassium and sulfur were obtained from analyzes by the UFSCar laboratory following specific procedures. The specific leaf area was negatively correlated with the leaf dry matter content and AF was not correlated with either SLA or LDMC. Our results showed that nitrogen, phosphorus, calcium, magnesium and potassium were positively correlated with the first axis of ACP. This axis was positively related to AFE and negatively related to CMSF. Pioneer species had higher values of these mineral elements in the leaves compared to non-pioneer species. Our study suggests that the concentrations of these minerals in the leaves may be indirectly related to the growth of plants and the resistance of plants to unfavorable environmental conditions found in degraded areas. The study showed that the specific leaf area was negatively correlated with leaf dry matter and that there is no correlation between the other characteristics. It also suggests that species with lower LDMC values had high values of SLA, being predominantly pioneer species, with leaves containing higher values of calcium, magnesium and phosphorus, suggesting greater photosynthetic capacity and probably higher rates of relative growth. Some non-pioneer plants with high LDMC have greater resistance in the leaves, being able to withstand physical hazards and desiccation, which can be an advantage in environments with high light intensity and low soil fertility, conditions generally found in degraded areas.