title: UV and visible light screening by individual sporopollenin exines derived from Lycopodium clavatum (club moss) and Ambrosia trifida (giant ragweed).
abstract: We have investigated the UV-visible light transmission of three types of micrometre-sized sporopollenin exine shells, two derived from Lycopodium clavatum (club moss) spores and one from Ambrosia trifida (giant ragweed) pollen. We have used spectrophotometer measurements of partial monolayers of exines and microscope absorbance imaging to derive the light transmission properties of individual exines. Measurements have been made for exines in air when light transmission losses are due to a combination of absorption, reflection and scattering processes and for exines dispersed in a liquid for which the refractive index (RI) is approximately equal to the RI of the exine such that reflection and scattering effects are negligible. Overall, it found that the light transmission of a single exine wall is approximately 50%. This value of the transmission is due mainly to light absorption, is similar for the three exines studied here and varies only slightly with light wavelength over the range 200-900 nm.
authors.affiliation: Sporomex Ltd., Department of Chemistry, University of Hull, Hull HU6 7RX, UK; Hull York Medical School, Michael White Diabetes Centre, 220-236 Anlaby Road, Hull HU32RW, UK.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Atkin
authors.forename: Sylvain
authors.initials: S
authors.lastname: Barrier
authors.forename: Zhenggang
authors.initials: Z
authors.lastname: Cui
authors.forename: Paul D I
authors.initials: PD
authors.lastname: Fletcher
authors.forename: Grahame
authors.initials: G
authors.lastname: Mackenzie
authors.forename: Vincent
authors.initials: V
authors.lastname: Panel
authors.forename: Vincent
authors.initials: V
authors.lastname: Sol
authors.forename: Xunli
authors.initials: X
authors.lastname: Zhang
mesh_terms: D031164:Ambrosia / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D002338:Carotenoids / Q000737:chemistry*; D032502:Lycopodium / Q000737:chemistry*; D008853:Microscopy; D055620:Optical Phenomena; D013056:Spectrophotometry, Ultraviolet; D014466:Ultraviolet Rays
chemical_list: D001704:Biopolymers; C009800:sporopollenin; D002338:Carotenoids