INITIAL GROWTHAND QUALITY OF Pterogyne nitens Tull.SEEDLING UNDER ARTIFICIAL SHADING GRADIENT

Abstract

Objetivou-se com este estudo avaliar o comportamento de plantas de Pterogyne nitens Tull. sob diferentes n\uedveis de restri\ue7\ue3o luminosa durante seu desenvolvimento inicial. O estudo foi conduzido no per\uedodo de mar\ue7o a junho de 2008, no campo agropecu\ue1rio da Universidade Estadual do Sudoeste da Bahia \u2013 UESB, em Vit\uf3ria da Conquista, BA. Sete experimentos foram definidos por n\uedveis de 20%, 30%, 40%, 50%, 60% e 70% de restri\ue7\ue3o luminosa e plantas mantidas a pleno sol. Cada um dos experimentos foi organizado em delineamento experimental inteiramente casualizado, com cinco repeti\ue7\uf5es e parcelas constitu\ueddas por 12 plantas. Durante o per\uedodo de 15 a 75 dias ap\uf3s a emerg\ueancia das pl\ue2ntulas, em intervalos de 15 dias, foram avaliadas as caracter\uedsticas morfol\uf3gicas e quantitativas de crescimento e o \uedndice de qualidade Dickson (IQD). Os gradientes de restri\ue7\ue3o de luz induziram a altera\ue7\uf5es morfol\uf3gicas como eleva\ue7\ue3o da altura e aumento da \ue1rea foliar individual e total das plantas. Redu\ue7\uf5es de massa do sistema radicular ocorreram em detrimento de tais modifica\ue7\uf5es. Invariavelmente, os maiores \uedndices de IQD foram verificados para as plantas mantidas sob 36,5% de restri\ue7\ue3o luminosa.The objective of this study was to evaluate the initial development and quality of seedlings Pterogyne nitens Tull., produced under different luminosity levels. The experiment was conducted from March to June 2008, in the agricultural field at the State University of Southwestern Bahia state - UESB, in Vitoria da Conquista, BA state. Seven experiments were defined for levels of 20%, 30%, 40%, 50%, 60% and 70% of light restriction and plants kept in full sun. For each experiment was followed the completely randomized design with five replications and each experimental unit was composed for12 plants. In a period from 15 to 75 days after the plant emergence, at intervals of 15 days, the morphological and quantitative characteristics of growth and quality index of Dickson (IQD) were evaluated. The constraint of light gradients induced morphological changes such as raising the height and increased individual and total leaf area of plants. Reductions in root system mass occurred at the expense of such modifications. Invariably, the highest rates were observed for the IQD plants lied under 36.5% light restriction