PS 40-118 - Shadows and growth potential in Campylocentrum fasciola 

Wednesday, August 9, 2017
Exhibit Hall, Oregon Convention Center
Julymar Rodríguez López and Raymond L. Tremblay, Biology, University of Puerto Rico at Humacao, Humacao, PR
Background/Question/Methods

Light is one of the most important factors in the growth and reproduction of plants. Even though epiphytes may seem to be continuously exposed to light, variation in light environment can influence growth and reproduction. In this case we evaluate the variation in light environment in the epiphytic leafless orchid Campylocentrum fasciola in two abandoned Psidium guajava and Miconia spp. farm in Caguas, Puerto Rico. We tested the hypothesis that light environment influences plant size and reproductive potential using the following indices: Leaf Area Index (LAI), Visible Sky, Indirect Site Factor and uniformity of canopy across the image measured with a Hemispherical Photography (Fisheye/Canopy Photography) above individual plants.

Results/Conclusions

We collected morphological information from 45 individuals and correlated the previous indices with the size of the plant, length of the longest root, number of roots, number of inflorescences, flowers and fruits using generalized linear models. Analysis was performed using different packages in R Studio and HemiView. When trying to determine what influences the number of roots we found a positive impact in LAI.1 (HemiView) while VisSky was negatively correlated. In other words, plants with more roots are positive influenced by shade (LAI) and this would explain that if they are reduced so is the number of roots. We also found a negative correlation between number of fruits and LAI, this indicates that plants with more LAI produce less fruits. The best model of relationship between the morphological and reproductive potential and the light environment tended to be non linear.