PROPAGAÇÃO VEGETATIVA, CRESCIMENTO E TEOR DA PROTEÍNA EM ORA-PRO-NÓBIS (Pereskia aculeata Miller) CULTIVADO SOB TELAS FOTOSSELETIVAS

Abstract

The use of photo-selective nets is an important agro-technological tool for crops. The manipulation of light through different photo-selective nets modifies the solar spectrum received by plants in terms of quantity and quality, thus modifying their physiological responses. This study was constituted by two experiments of ora-pro-nóbis (Pereskia aculeata Miller), one to evaluate the growth and development of seedlings from cuttings and the other cultivated in soil under photo-selective nets and in full sun. In the first experiment, the objective was to evaluate the vegetative growth of seedlings produced from cuttings. In the second experiment, the objective was to evaluate the vegetative growth and protein content of plants grown in the soil from seedlings. For the experiments, sheds were constructed in wooden structures, 5.0 x 4.0 x 1.70 m (length, width and ceiling height), with a central post with a height of 2.0 m. Each wooden structure was covered individually, on the top and on the sides, with respective ChromatiNet® Leno Azul, ChromatiNet Leno Pérola, ChromatiNet® Leno Vermelha, all with 20% shading. In the first experiment the seedlings were prepared in polyethylene bags 10 x 15 x 0.10 cm (width, length and thickness) each containing a 20 cm stem cutting removed from the branch of the year. The experiment was conducted in a randomized block design, with four replications and ten plants per plot, arranged side by side, making a total of 160 seedlings, which were placed under the photo-selective nets and in full sun (control). After sixty days of cultivation, growth characteristics were evaluated: number of shoots, length of shoots, number of leaves, fresh and dry mass of leaves, stems and roots. The second experiment was conducted in a randomized block design (DBC), in subdivided plots in time, with four replications. The main plot was composed of four treatments (photo-selective and full sun) and the subplot (secondary treatment) consisting of two sampling times, at 80 and 120 days after transplanting (DAT) of the seedlings. Soil planting was carried out using seedlings from cuttings, grown in nursery, for a period of 40 days. The characteristics evaluated in the samplings were: protein content, number of leaves, number of main and lateral buds, root length, plant height, lap diameter, fresh and dry mass of leaves, stems and roots. It was observed that ora-pro-nóbis plants respond to the modification of the light spectrum provided by the photo-selective nets. In the first experiment, the pearl net presented higher averages for the parameters fresh and dry mass of leaf and root and number of leaves. The blue net presented better results for dry stem mass, plant height and length of the main shoot and the red screen for the number of shoots. In the second experiment, in the sampling at 80 DAT, the treatments did not differ among each other, except for the protein content that under the red net obtained the lowest average. In the sampling at 120 DAT, the pearl net obtained the highest averages for fresh leaf mass, leaf and stem dry mass, leg diameter and number of leaves; the red net provided a higher average for dry leaf mass. Knowing that the leaves constitute the main product of consumption of the plant, the cultivation of ora-pro-nóbis under the pearl net with 20% of shading, would be the most recommended.