Aclimatização de brassavola martiana e oeceoclades maculata (orchidaceae) sob condições de campo

Abstract

Studies aiming the acclimatization of orchid species originated from in vitro cultures and their reintroduction in environments as a means to recover declining populations are highly relevant. In light of that, the objective of the present investigation was to study the acclimatization of Brassavola martiana and Oeceoclades maculata under field conditions. The individuals of B. martiana and O. maculata used in this study were obtained through in vitro culture and were initially growing in plastic pots containing a commercial substrate at the Neamb/UFT shade-house with 75% retention of solar radiation flux. In the field the individuals of B. martiana were tied to eight specimens of three species of phorophytes. Three individuals of B. martiana were placed in each of the phorophytes (n=24). Phorophyte species were Syagrus cocoides (Arecaceae) located at Vila da Mata Farm, and Alibertia sessilis (Rubiaceae) and Astronium fraxinifolium (Anacardiaceae) located at the Neamb/UFT Woods, both in the County of Porto Nacional, Tocantins. The individuals of O. maculata were planted in two sub-areas at the Neamb/UFT Woods, 20 meters away from each other. Fifteen individuals, maintaining a minimum distance of 2 meters between them, were planted in each sub-area (n=15). The evaluation was based on survival percentage and developmental of the individuals assessed by plant height and the number of leaves, shoots and roots produced 15 months after the beginning of the study. S. cocoides provided 70.83% survival of B. martiana individuals and 61.8% of the formed shoots were present at the end of the study. The development of the individuals in S. cocoides was very satisfactory and occurred essentially throughout the rainy season. This shows that this phorophyte was efficient for the acclimatization and development of this orchid species. A. fraxinifolium provided 54.20% survival of B. martiana individuals whereas in A. sessilis survival percentage was 20.83% only. The development of this orchid species did not differ greatly between this two phorophyte species. Survival of O. maculata was 73.33% in sub-area 1 and 33.33% e sub-area 2. Only the height differed statistically between the areas, which was higher in subarea 1, which also provided the best development of the individuals, possibly due to a higher water retention through the clay content in the soil and the higher luminous intensity recorded there.