Caracterização morfológica de frutos, sementes e plântulas, germinação e micropropagação de Terminalia fagifolia e Terminalia argentea (Combretaceae)

Abstract

The study aimed to, morphologically characterize fruits, seeds and seedlings of Terminalia fagifolia and Terminalia argentea and evaluate the physiological quality of seeds and develop a method for micropropagation for both species. For morphological, 100 and 100 fruit seeds, including features such as color, texture , length , width and morphological structures were evaluated were sampled . Moisture was determined by oven method at 103 ° C ± 2 . Germination was carried out in a germination chamber BOD using type Gerbox ( 15x15 cm ) boxes containing sterilized sand and distilled water with a temperature of 30 ° C and 16 h photoperiod . , Scarification on Emery , PA scarification with sulfuric acid for 5 minutes, immersion in boiling water for 5 minutes , and soaking in water at room temperature for 24 hours Control : The following treatments to break dormancy were tested. The moisture and germination were performed on freshly harvested and 2 , 4 and 6 months of storage in cold camera seeds . For disinfestation were mounted four experiments . At first, the seeds of T. fagifolia were washed, scarified in sulfuric acid for 5 minutes and then immersed in 70% alcohol for 30 seconds and, subsequently , in a solution of sodium hypochlorite 5 % with added 4 to 5 drops of Tween 20 per 100 ml of solution. Immersion times of 5 , 10, 15 , 20 and 25 minutes in a sodium hypochlorite 5 % , which constitute five treatments were used. In experiment II, the procedures were similar to those described in experiment I, differing with respect to treatments. Immersion times of 5, 10, 15, 20 and 25 minutes in a solution of chlorhexidine gluconate to 5 mgL - ¹ were tested. In the experiments III and IV, T. argentea, the procedures were similar to the experiment, however, in Experiment IV, the seeds were removed from their integument. After desisnfestação seeds were inoculated and test tubes with 10 ml of MS medium. In the multiplication phase, for the first subculture, seedlings of T. argentea obtained in the previous step experiment IV were segmented and their nodal segments were inoculated in MS medium plus 0.03 mg L - ¹ and BAP at concentrations of 0.1, 0.15, 0.2 , 0.4 and 0.6 mg L- 1. For 1 and 2 subcultures , shoots originating from the initial subculture and 1 , respectively , growing axillary buds were inoculated into test tubes containing 10 ml of the basic culture medium added 0.15 mg L- ¹ BAP and 0.03 mg L- ¹ NAA. For rooting , the plantlets subculture of 2 longer than 2 cm were inoculated in studies containing 10 ml of MS medium supplemented with 0 , 1.0, 2.0 and 4.0 mg L - ¹ IBA . Generally, the storage time and the pre- germination treatment did not affect the germination of T. fagifolia . T. argentea storage for two months and immersion in water for 24 hours resulted in the highest germination percentages. For in vitro disinfection with sodium hypochlorite and chlorhexidine gluconate were not effective to promote decontaminating seeds, however, the removal of the seed coat and soaking the seeds for 25 minutes in a solution of sodium hypochlorite at 2.5% proved to promote efficient disinfection and germination in vitro of T. argentea. In the multiplication phase the addition of 0.15 mg L - ¹ BAP favored the emergence of shoots in nodal segments of T. argentea while the addition of 4.0 mg L - ¹ BAP to the culture medium favored rooting for this species.