Host suitability for germination differs from that of later stages of development in a rare epiphytic orchidResumen
Exploramos la utilización de árboles y los patrones de germinación de la orquídea epífita, Psychilis kraenzlinii. Encontramos que P. kraenzlinii crece en un subconjunto de las especies de árboles disponibles y muestra preferencia por la endémica Machaonia portoricensis. La orquídea prefiere árboles con corteza lisa y alta capacidad de sostener agua y baja capacidad de retención de agua. Las condiciones microclimáticas bajo las cuáles los embriones empienzan etapas pre-germinacíon, reflejan los de la orquídea adulta, pero las condiciones bajo las cuáles los embriones llegan a etapas de germinación no. Lo que sugiere que los sitios de germinación adecuados no son necesariamente los lugares donde mejor se producirá el desarrollo a etapas más avanzadas de la germinación.
Palabras clave: dinámica comunitaria; dinámica poblacional; epífitas; forófitos; germinación; Orchidaceae
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B. Average number of P. kraenzlinii growing on the most common phorophyte species (Plus sign (+) marks a positive and significant association, whereas minus sign (-) marks a negative significant association.Associations based on residuals from Fisher Exact Test with Monte Carlo Simulation (p < 0.05, simulations = 2000).
B. Box plots of the fissuring index of the bark of trees with and without Psychilis kraenzlinii among phorophyte species.Randia aculeata and Swietenia mahagoni not shown because data of trees with a P. kraenzlinii was not available.Red brackets with asterisks mark significant differences where: * = p ≤ 0.05; **= p ≤ 0.01; ***= p ≤ 0.001.
Where Stage 1 refers to seeds with swollen embryos, Stage 2 are seeds whose embryo have swelled to the point of breaking the testa, Stage 3 the testa is gone and the protocorm is formed, and Stage 4 the protocorm has elongated.For Ouratea littoralis, no seeds developed near an established P. kraenzlinii, whereas in the case of Coccoloba microstachya and Randia aculeata, no packets were placed near and established orchid.Red lines indicate significant differences according to Conover-Iman Pairwise Comparisons (p<0.05).
Photos by N. González-Orellana.A. Pictures of the bark surface of Coccoloba microstachya taken with a camera coupled to a dissecting microscope and a ring light. B. Pictures of the bark surface of Phyllanthus cuneifolius taken with a camera coupled to a dissecting microscope and a ring light. C. Photos converted to black and white (binary) images of C. microstachya. D. Photos converted to black and white (binary) images of P. cuneifolius. Enclosed in red is the area where roughness interpretation could be affected by bark pigmentation.