Germination potential of seeds and keikis quality of Dendrobium nobile at different fruit development stages/Potencial germinativo de sementes e qualidade de keikis de Dendrobium nobile em diferentes fases do desenvolvimento dos frutos

• Published in: Ciência rural 2015-11, p.1965
• Main Authors: Sorgato, Jose Carlos, Soares, Jackeline Schultz, Pinto, Jannaina Velasques da Costa, Rosa, Yara Brito Chaim Jardim
• Format: Article
• Language: Spanish
• ISSN: 0103-8478
• DOI: 10.1590/0103-8478cr20141129

The objective of this study was to evaluate the germination potential of seeds formed by manual self pollination in fruits of pseudobulbs of Dendrobium nobile in different maturation stages. At 90, 120, 150, 180, 210, 240, 270 and 300 days after pollination (DAP), five pseudobulbs containing fruits, were detached from the mother plant and planted in a polypropylene container, where they remained until 300 DAP. After this period, the pseudobulbs were evaluated on the number of keikis and all keikis produced as the diameter and length of pseudobulb, number of leaves and roots. After, the fruits were detached from pseudobulbs, and evaluated as the diameter of the largest portion of the ovary, length and fresh weight of fruit, fresh weight of seed and pericarp. For each collecting period of fruits, seeds were tested with tetrazolium test and germination test. The larger the diameter of the fruit, the percentage of viable seeds and the germination percentage of D. nobile also increased, and this relationship was growing as they increase the length of fruit stay on the mother plant. Morover, the pseudobulbs remained shortest time in the mother plant showed higher numbers of keikis and so that the percentage of germination in vitro of D. nobile is above 75%, the pseudobulbs, containing fruit, should be collected from the 166 DAP. Key words: orchids fruit, germination in vitro, propagation. Objetivou-se com este trabalho avaliar o potencial germinativo das sementes, formadas por autopolinizacao manual, em frutos de pseudobulbos de Dendrobium nobile, em diferentes estagios de maturacao. Aos 90, 120, 150, 180, 210, 240, 270 e 300 dias apos polinizacao (DAP), cinco pseudobulbos contendo frutos foram destacados da planta-mae e plantados em recipiente de polipropileno, permanecendo ate 300 DAP. Depois desse periodo, os pseudobulbos foram avaliados quanto ao numero de keikis e os keikis produzidos quanto ao diametro e comprimento de pseudobulbo, numero de folhas e de raizes. A seguir, os frutos foram destacados dos pseudobulbos e avaliados quanto ao diametro da maior porcao do ovario, comprimento e massa fresca do fruto, massa fresca das sementes e do pericarpo. Para cada epoca de coleta de frutos, as sementes foram submetidas ao teste de tetrazolio e ao teste de germinacao. Quanto maior o diametro do fruto, a porcentagem de sementes viaveis e a porcentagem de germinacao de D. nobile tambem aumentaram, e essa relacao foi crescente a medida que aumentam os dias de perman