Conservation of Schomburgkia crispa Lindl. (Orchidaceae) by reintroduction into a fragment of the Brazilian Cerrado

Asymbiotic germination of native orchids is an important technique for producing seedlings for use in species reintroduction programs, as it facilitates the maintenance of genetic variability. The objective of this study was to evaluate the adaptive responses of Schomburgkia crispa Lindl. (Orchidaceae) in an area undergoing environmental restoration, and to compare the efficacy of traditional and alternative substrates in order to contribute to the management and reintroduction of this species. Plants of S. crispa were obtained from asymbiotic sowing, and acclimated plants (ACP) were reintroduced in an underbrush area at the State University of Mato Grosso do Sul using three planting treatments: without substrate (WS); buriti stem substrate (BU); and, coconut fiber substrate (CF). Stress was assessed based on chlorophyll a fluorescence measurements and infrared thermography, and the growth environment was evaluated for light conditions and canopy cover. A completely randomized design was used with three treatments, each consisting of one substrate, with 10 single-plant replicates. After 850 days, fluorescence and survival of established plants (ESP) were re-evaluated. At 21 days after reintroduction, the plants showed 100% survival regardless of the substrate used, these values reached 73.3% for ESP plants. The largest variations between the temperature of the phorophytes and the temperature of the epiphytic orchid plants occurred on the day of reintroduction. There was no significant difference in the potential quantum efficiency of photosystem II (PSII: Fv/Fm) among treatments for ACP plants showed lower values of potential quantum efficiency (Fv/F0) to WS. Although the different substrates until 21 days did not significantly affect plant survival, temperature, or the photochemical efficiency of PSII, when ACP and ESP plants were compared, the quantum efficiency were significantly higher to acclimated plants indicating the better adjustment of the photosynthetic apparatus after 850 days justifying the high survival percentage. These data highlight the ability of S. crispa to resist in a heterogeneous light environment even through coming from asymbiotic sowing.