Felipe Gómez-Noguez1, César Domínguez-Ugalde2, Catalina Flores-Galván3, Luis Manuel León-Rossano4, Blanca Pérez García5, Aniceto Mendoza-Ruiz6, Irma Rosas-Pérez7, Klaus Mehltreter3. 1. Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n, Ciudad Universitaria Sur, Chilpancingo de los Bravo, Guerrero, 39086, México. 2. Licenciatura en Biología, Universidad Autónoma Metropolitana-Iztapalapa, Av. Ferrocarril de San Rafael Atlixco 186, Col. Leyes de Reforma 1ª Sección, Ciudad de México, 09310, México. 3. Red de Ecología Funcional, Instituto de Ecología A. C. Carretera Antigua a Coatepec No. 351, El Haya, Xalapa, Veracruz, 91073, México. 4. Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, 04510, México. 5. Área de Botánica Estructural y Sistemática Vegetal, Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Av. Ferrocarril de San Rafael Atlixco 186, Col. Leyes de Reforma 1ª Sección, Ciudad de México, 09310, México. 6. Área de Botánica Estructural y Sistemática Vegetal, Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa. Av. Ferrocarril de San Rafael Atlixco 186, Col. Leyes de Reforma 1ª Sección, Ciudad de México, 09310, México. 7. Instituto de Ciencias de la Atmósfera y Cambio Climático, Universidad Nacional Autónoma de México, Circuito exterior s/n, Coyoacán, Ciudad Universitaria, Ciudad de México, 04510, México.
Abstract
PREMISE: Terminal velocity (Vt) is an important factor for the dispersal of biological particles but has scarcely been studied for anemochorous fern spores, and the influence of spore characteristics on Vt has not been evaluated. Here, we measured the Vt of 1234 spores of 18 fern species and two Selaginella microspores using videoimaging analysis and evaluated the effects of mass, size, and ornamentation on Vt. METHODS: We designed a sedimentation tower with a graduated microtelescope attached to a high-speed video camera to record falling particles and measure the Vt of fern spores using video-image processing software. Spores were measured for each species and their size correlated with Vt. RESULTS: The Vt of fern spores ranged from 4.7 cm·s-1 (Cyathea costaricensis) to 18.85 cm·s-1 (Acrostichum danaeifolium). The method is accurate and reliable as predicted by Stokes model for glass beads of known density and size. In addition, Vt had a higher correlation coefficient with mass (ρ = 0.72) than size (ρ = 0.20), and ornamental appendages reduced Vt. CONCLUSIONS: The reported values of Vt of fern spores are within the range of different biological airborne particles such as moss spores and pollen grains of seed plants. The results showed that spore ornamentation is directly related to Vt rather than spore size and may increase or decrease the drag. This method will aid future aerobiological research on biological particles.
PREMISE: Terminal velocity (Vt) is an important factor for the dispersal of biological particles but has scarcely been studied for anemochorous fern spores, and the influence of spore characteristics on Vt has not been evaluated. Here, we measured the Vt of 1234 spores of 18 fern species and two Selaginella microspores using videoimaging analysis and evaluated the effects of mass, size, and ornamentation on Vt. METHODS: We designed a sedimentation tower with a graduated microtelescope attached to a high-speed video camera to record falling particles and measure the Vt of fern spores using video-image processing software. Spores were measured for each species and their size correlated with Vt. RESULTS: The Vt of fern spores ranged from 4.7 cm·s-1 (Cyathea costaricensis) to 18.85 cm·s-1 (Acrostichum danaeifolium). The method is accurate and reliable as predicted by Stokes model for glass beads of known density and size. In addition, Vt had a higher correlation coefficient with mass (ρ = 0.72) than size (ρ = 0.20), and ornamental appendages reduced Vt. CONCLUSIONS: The reported values of Vt of fern spores are within the range of different biological airborne particles such as moss spores and pollen grains of seed plants. The results showed that spore ornamentation is directly related to Vt rather than spore size and may increase or decrease the drag. This method will aid future aerobiological research on biological particles.