Caracterização morfológica das sementes, germinação e estabelecimento in vitro de Cambessedesia hilariana

Abstract

The species Cambessedesia hilariana is endemic to Brazil, native to the Cerrado, very present in the rupestrian field environment and endowed with attributes for use in landscaping. Thus, it is necessary to know the characteristics of the seed and its germination for further research on large-scale propagation. This work aimed at the morphological characterization of seeds and seedlings of Cambessedesia hilariana (Kunth) DC. var. hilariana and Cambessedesia hilariana (Kunth) DC. var. longifolia as well as the in vitro establishment of Cambessedesia hilariana (Kunth) DC. var. hilarious. The fruits were collected in the municipality of Diamantina (MG). In the first stage of the work, analyzes were carried out in the Seed Analysis and Cultivation Laboratory of the Instituto de Ciências Agrárias – UFMG to describe the morphology of the seeds and germination of the two varieties (color, texture, weight, fresh mass, dry mass, image tests and IVG). The design was completely randomized using the Skott-Knott test. In the second stage, which consisted of in vitro establishment, only the variety Cambessedesia hilariana (Kunth) DC. var. hilariana was analyzed, and the tests took place at the Forestry Improvement Laboratory of the Institute of Agricultural Sciences – UFMG. At this stage, four asepsis treatments were carried out with 10 repetitions of each, and all of them were sequentially immersed in 70% alcohol, Sodium Hypochlorite in different proportions and a drop of detergent. Then the second treatment received Derosol® Plus fungicide; in the third, lemongrass was used; and the fourth treatment was the witness only the triple wash. Sixty days later, four subcultivation tests were carried out in two media (MS and WPM), with and without the presence of activated carbon and agar gelling agent, and only one treatment with MS medium and Phytagel®. The design was entirely randomized, and Probit, Krushal-wallis and Chi-square tests were performed for the variables analyzed. Results revealed that, comparing the two varieties, the seeds of Cambessedesia hilariana (Kunth) DC. var. hilariana present a darker coloration in relation to the other variety, but there were no significant differences for the biometric measurements. The average germination speed index showed similar values between the varieties analyzed, and germination succeeded satisfactorily on the 5th day after inoculation. The image test revealed that both varieties have a rough surface with aligned scales. In the second stage, it was observed that, in the treatment with the presence of the fungicide, no contamination occurred in any of the samples, and that the MS culture medium in the presence of Phytagel® presented superiority in relation to the WPM for most of the characteristics studied. In addition, the use of activated carbon stabilized the accumulation of phenolic oxidation. The research data showed important morphological characteristics of the seeds of the two varieties studied and possibility of in vitro establishment of Cambessedesia hilariana (Kunth) DC. var. hilariana, but further studies are needed for large-scale propagation.