Tecnologia de sementes de Handroanthus impetiginosus (Mart. ex DC.) Mattos

Abstract

Handroanthus impetiginosus popularly known as ipê pink is a native species of Brazilian trees with large occurrence, mainly in the semideciduous forest. Its exuberant flowering favors the use in urban afforestation, landscaping and reforestation. Among the factors that affect the germination process, the temperature, light and substrate assume a prominent role, insofar as it determines the seed germination capacity and germination rate. Knowledge of the behavior of forest seeds under different storage conditions is extremely important for the rational management of the species. The experiments were conducted in the Laboratory of Analysis of Seeds-LAS, at the Federal Rural University of Pernambuco-Academic Unit of Garanhuns-UAG / UFRPE with the objective of studying suitable conditions for the germination test of H. impetiginosus seeds and the physiological alterations and biochemistry associated with germination and viability during storage of H. impetiginosus seeds. The first experiment evaluated the influence of temperatures and substrates on the germination of H. impetiginosus seeds. Six temperatures (15, 20, 25, 30, 35 and 40 ° C) and five substrates (sand, on sand, roll of paper, on paper and between paper); (15, 20, 25, 30, 35 and 40 ° C) and four light regimes (white, red, distant red and dark) were tested in the second experiment and evaluated the effect of different temperatures and light regimes. third experiment the physiological and biochemical changes of H. impetiginosus seeds submitted to storage in three environments (laboratory environment, refrigerator and freezer) and three containers (plastic container, plastic bag and paper bag). Initially and at each storage period the water content of the seeds was determined and the following variables were evaluated; percentage and germination speed index, length and total dry mass of seedlings. For the evaluation of substrates and temperatures, the highest percentages of germination, germination speed index and seedling length were obtained in the temperature range of 27 ° C on substrates between sand and paper roll. The results obtained when evaluating light and substratum regimes showed that a higher percentage of germination (92%) and a rate of germination (7.94) were obtained at temperatures 28.2 and 29.2 ° C respectively in the red light regime. With the storage of seeds, a significant effect was observed for most of the treatments and their interactions, except for the germination speed index, the packaging variation factor and the environmental interaction x packaging. The constant temperatures of 27.2 and 27.7 ° C in the paper roll and sand substrates are the most recommended for the germination of Handroanthus impetiginosus seeds. The seeds of ipê pink are classified as neutral photoblasts; the seed germination test can be evaluated at constant temperatures of 28.2 and 29.2 ° C under a red and white light regime. The seeds of H. impetiginosus can be stored in a freezer or refrigerator to maintain viability and vigor, stored in a plastic container or plastic bag, for 150 days. The electrical conductivity test is efficient to evaluate seed vigor during storage.