CHARACTERIZATION OF SEEDS, SEEDLINGS AND INITIAL GROWTH OF JACARANDA MIMOSIFOLIA D. DON. (BIGNONIACEAE)

ABSTRACT This research aimed to characterize the biometry of seeds, the morphology of seedlings and to evaluate the initial growth of blue jacaranda trees (Jacaranda mimosifolia D. Don.) in two environments with distinct luminosity. The biometry of 100 de-winged seeds was measured by their length, width and thickness. One hundred seeds were sown into 300 cm3 tubes and seedlings morphology was registered throughout the germination process using digital photographs disposed sequentially according to seedlings age. The initial growth analysis was performed in two environments, full sun and greenhouse, during nine periods, and arranged in a complete randomized design with subplots. The response variables were: number of leaves, plant height, collar diameter, root length, aerial and roots dry weight, and Dickson’s Quality Index (DQI). Biometry results showed seeds 7.09 - 9.26 mm long, 6.74 -9.39 mm wide, and 1.11 -1.89 mm thick. Germination is of hypogealphanerocotylar type, with first root arising six days after sown. Plants at full sun presented larger collar diameters, greater root dry weight and higher DQI as evaluation periods passed by. In conclusion, the biometry of seeds and the morphology of seedlings of blue jacaranda can be used to recognize this species in the field. Plants at full sun presented better development. Seedlings cultivated at full sun can be destined to recuperate forests and degraded areas just 36 weeks after sowed. RESUMO Objetivou-se nesta pesquisa fazer a caracterização biométrica das sementes, morfologia das plântulas de Jacaranda mimosifolia D. Don. e avaliar o crescimento inicial das mudas em dois ambientes distintos com diferentes níveis de luminosidade. Para a biometria de sementes, utilizou-se 100 sementes sem as partes aladas para a mensuração do comprimento, largura e espessura. Para a morfologia das plântulas, semeou-se 100 sementes em tubetes de 300 cm3, registrando-se os eventos do processo germinativo através de fotos digitais e dispondo-as de forma sequenciada de acordo com a idade das plântulas. A análise de crescimento inicial foi realizada em sol pleno e estufa agrícola durante nove épocas num esquema de parcelas subdivididas, em delineamento inteiramente casualizado. As variáveis respostas foram: número de folhas, altura da planta, diâmetro do coleto, comprimento da raiz, massa seca da parte aérea e raiz, bem como, o índice de qualidade de Dickson (IQD). O comprimento das sementes variou de 7,09 a 9,26 mm, a largura