Crescimento inicial de mudas de Ormosia arborea sob diferentes níveis de luz

Abstract

The information on the growth of plants in response to light are essential for the production of quality seedlings. Among the variables to be analyzed leaf area is important because the leaves are mainly responsible for the production of organic matter through photosynthesis, however, due to the variability and morphological characteristics of the species, leaf area methods should always be compared to others for set accuracy. This work aimed to evaluate the effect of different light intensity in the initial growth of Ormosia arborea and compare the quality of measurement of two destructive methods of leaf area (leaf area of integrator method and method of the fresh weight of leaf discs). Therefore the seedlings of this species were separated into three light conditions: 30%, 70% and 100% light (Full sun) and evaluated at 0, 30, 60, 90, 120 and 180 days after the transfer of seedlings to the different lighting conditions. The parameters analyzed were shoot length, root and total (cm); total dry mass (g) and leaf area (cm2), which made the use of two methods of measurement: integrative method of leaf area and fresh mass method of leaf discs. It was observed that all O. arborea seedlings survived until the end of the experiment in all treatments, and shoot length, and total leaf area showed higher values in the presence of lower light intensity (30%), while length root was higher in full sun, however shading levels did not affect the dry matter accumulation of plants, allowing to conclude that O. arborea develops fit to survive in different light intensities. As for leaf area estimation methods, both the integrator method of leaf area as the fresh dough method of leaf discs are efficient for O. arborea and the advantages and disadvantages of each must be analyzed according to where the work will be developed and disponibility of resources.