Desenvolvimento de mudas de quatro espécies florestais produzidas em diferentes níveis de sombreamento e plantadas em pleno sol

Abstract

Success in planting seedlings of native forest is dependent on previous light condition in which they were developed before planting, and other factors. This initial condition can influence both positively and negatively the establishment of the plant in the field under full sun, which can be used to guide the most efficient method of production. This work aimed to verify the initial growth of plant species Schinus terebinthifolius Raddi (aroeira), Schinopsis brasiliensis Engl. (braúna), Plathymenia reticulata Benth (vinhático) and Dalbergia nigra (Vell.) Fr All. ex Benth. (jacarandá) in sunny conditions, originating from seedlings at different levels of shading (0, 22, 50, 70, 84 and 91%) for the first three species and at levels 0% to 70% shading for braúna. The levels of shading were obtained with use of appropriate shade, being scanned using a bar ceptômetro - AccuPAR - Model LP PAR 80). When the seedlings, grown in the different levels of shading, were about 9 months after sowing, they were planted in full sun, taking the spacing of 70 x 70 cm. The plants chosen were those considered most healthy (largest diameter, height and number of leaves) and the evaluation was height (ALT), diameter at ground level (DNS), leaf area (LA), root dry matter (RDM) , stem dry matter (MSC) dry leaves matter (MSF), shoot dry matter (MSA), total dry matter (MST), ratio root / shoot (RRPA), leaf mass ratio (LWR), leaf area ratio (RAF) specific leaf area (AFE). The initial growth of the species Schinus terebinthifolius Raddi (aroeira) after 8 months in full sun was favored by 22% to 35% shade. The plants of species Schinopsis brasiliensis Engl. (braúna) from seedlings grown in 0% shade had the best features of initial growth in full sun. Plants of Dalbergia nigra (Vell.) Fr All. ex Benth. (jacarandá), after planting in the field and 8 months in full sun, showed the best morphological those coming from seedlings grown in 84% and 91% shading. The only species that, after 8 months in the field under full sun, did not respond to initial shading was Plathymenia reticulata Benth (vinhático).