Ultraviolet leaf reflectance of common urban trees and the prediction of reflectance from leaf surface characteristics

The spectral reflectance and transmittance over the wavelength range of 250–700 nm were evaluated for leaves of 20 deciduous tree species and leaf sheaths of five isogenic wax variants of Sorghum bicolordiffering in visible reflectance due to cuticular waxes. Using the sorghum sheath reflectance and cuticle surface characteristics as a model, it was concluded that tree leaf reflectance above 0.06 was likely due to the presence of variously-shaped fine epicuticular wax structures on the leaf surface. Increasing the density of sub-micron wax structures corresponded to an enhanced ultraviolet (UV) reflectance over the PAR reflectance of a given leaf surface—either S. bicolor sheath or tree leaf. Amorphous globular epicuticular wax structures did not appear to scatter UV as well as wax filaments or vertical plates in varying patterns even when the dimensions of the structures were similar. Further work is needed to clarify this relationship and the influence of cellular pigments on subsurface contributions to the reflectance. © 2003 Elsevier B.V. All rights reserved.

[1]  William K. Smith,et al.  Contribution of intercellular reflectance to photosynthesis in shade leaves , 1996 .

[2]  L. Grant.  Diffuse and specular characteristics of leaf reflectance , 1987 .

[3]  L. Fukshansky.  Photon Transport in Leaf Tissue: Applications in Plant Physiology , 1991 .

[4]  R. H. Grant.  Partitioning of biologically active radiation in plant canopies , 1997 .

[5]  D A Reicosky,et al.  Physiological Effects of Surface Waxes: I. Light Reflectance for Glaucous and Nonglaucous Picea pungens. , 1978, Plant physiology.

[6]  William K. Smith,et al.  Chlorophyll and light gradients in sun and shade leaves of Spinacia oleracea , 1991 .

[7]  D. E. Escobar,et al.  Ultraviolet Radiation Reflectance, Transmittance, and Absorptance by Plant Leaf Epidermises1 , 1975 .

[8]  A. Kootstra.  Protection from UV-B-induced DNA damage by flavonoids , 1994, Plant Molecular Biology.

[9]  J. Rozema,et al.  Ultraviolet-B (280 − 320 nm) absorbing pigments in the leaves of Silene vulgaris : their role in UV-B tolerance , 1995 .

[10]  Gordon M. Heisler,et al.  Radiative properties of hardwood leaves to ultraviolet irradiation , 1995 .

[11]  Ranga B. Myneni,et al.  Photon-Vegetation Interactions , 1991, Springer Berlin Heidelberg.

[12]  J. Woolley.  Reflectance and transmittance of light by leaves. , 1971, Plant physiology.

[13]  C. Tucker,et al.  Leaf optical system modeled as a stochastic process. , 1977, Applied optics.

[14]  L. Björn,et al.  Effects of increased solar ultraviolet radiation on terrestrial ecosystems , 1998 .

[15]  T. Day,et al.  Penetration of UV‐B radiation in foliage: evidence that the epidermis behaves as a non‐uniform filter , 1993 .

[16]  Yiannis Manetas,et al.  Ultraviolet‐B radiation absorbing capacity of leaf hairs , 1992 .

[17]  Thomas G. Kyle,et al.  Atmospheric Transmission, Emission and Scattering , 1991 .

[18]  J. Norman,et al.  Leaf Optical Properties , 1991 .

[19]  Richard H. Grant,et al.  Scattering of ultraviolet and photosynthetically active radiation by sorghum bicolor: influence of epicuticular wax , 1995 .

[20]  M. G. Holmes,et al.  Effects of pubescence and waxes on the reflectance of leaves in the ultraviolet and photosynthetic wavebands: a comparison of a range of species , 2002 .

[21]  D Rhodes,et al.  Leaf sheath cuticular waxes on bloomless and sparse-bloom mutants of Sorghum bicolor. , 2000, Phytochemistry.

[22]  W. Rice,et al.  Ultraviolet absorption and epidermal-transmittance spectra in foliage , 1994 .

[23]  Markus Riederer,et al.  Attenuation of UV radiation by plant cuticles from woody species , 1997 .

[24]  E. Ashworth,et al.  Epicuticular Wax Morphology of Bloomless (bm) Mutants in Sorghum bicolor , 1992, International Journal of Plant Sciences.

[25]  D. M. Gates,et al.  Spectral Properties of Plants , 1965 .

[26]  J. Clark,et al.  Photosynthetic Action Spectra of Trees: II. The Relationship of Cuticle Structure to the Visible and Ultraviolet Spectral Properties of Needles from Four Coniferous Species. , 1975, Plant physiology.