TY - JOUR
T1 - A spectrofluorometric survey of UV-induced blue-green fluorescence in foliage of 35 species
AU - Johnson, Gregory A.
AU - Mantha, Sailaja V.
AU - Day, Thomas
N1 - Funding Information:
We thank D. J. Pinkava for assistance in identification of plant specimens, J. K. Hoober for use of the spectrofluorometer, and N. 1. Maniga for assistance with preliminary spectra measurements. This work was supported by u.s. Department of Agriculture competitive grant 97351004212 to T. A. Day and W D. Clark and an NSF Graduate Research Traineeship DGE-9553456 supporting G. A. Johnson. This is publication number 414 from the Photosynthesis Center at Arizona State University.
PY - 2000/2
Y1 - 2000/2
N2 - Upon excitation by ultraviolet radiation (UV), plant foliage exhibits a blue-green fluorescence (BGF). In order to assess the prevalence and variability of this fluorescence we examined UV-induced blue-green fluorescence from foliage surfaces of 35 species comprising seven life forms (grasses/sedges, conifers herbaceous dicotyledons, succulents, palms, woody deciduous dicotyledons, and woody evergreen dicotyledons) growing in Tempe, AZ, USA. Excitation (260-380 nm) and emission (400-600 nm) spectra of the adaxial and abaxial surfaces of foliage from five non-stressed plants of each species were measured with a spectrofluorometer. When excited with UV all species had violet to blue emission peaks (range = 405475 nm; adaxial mean = 443 ± 1 nm (SE), abaxial mean = 442 ± 1 nm), while about a third also had a well-defined green emission peak (range = 510-550 nm; adaxial mean = 523 ± 1 nm, abaxial mean = 524 ± 1 nm) and one species also had a yellow emission peak at 568 nm. Fluorescence excitation peaks ranged from 285-370 nm (mean adaxial excitation peak = 342 ± 1 nm and mean abaxial excitation peak = 341 ± 1 nm) among surveyed species. There was a significant positive correlation between adaxial and abaxial excitation peak wavelengths (r = 0.66), as well as between adaxial and abaxial emission peak wavelengths (r = 0.97). To quantify and compare emission peak intensities among species we determined a fluorescence yield index (FYI) calculated as the emission peak energy divided by total incident excitation energy. The FYI varied over an order of magnitude among species. On average, grasses/sedges and succulents had significantly greater FYIs than the other five life forms. The FYI of blue (<500 nm) adaxial emission was strongly correlated (r = 0.76) with abaxial emission. Our findings suggest BGF may be caused by several compounds in addition to cell-wall-bound ferulic acid which can vary among species but appear to be similar on adaxial and abaxial foliage surfaces within a species. The large range in FYI suggests some species may possess considerably greater amounts of BGF compounds than others.
AB - Upon excitation by ultraviolet radiation (UV), plant foliage exhibits a blue-green fluorescence (BGF). In order to assess the prevalence and variability of this fluorescence we examined UV-induced blue-green fluorescence from foliage surfaces of 35 species comprising seven life forms (grasses/sedges, conifers herbaceous dicotyledons, succulents, palms, woody deciduous dicotyledons, and woody evergreen dicotyledons) growing in Tempe, AZ, USA. Excitation (260-380 nm) and emission (400-600 nm) spectra of the adaxial and abaxial surfaces of foliage from five non-stressed plants of each species were measured with a spectrofluorometer. When excited with UV all species had violet to blue emission peaks (range = 405475 nm; adaxial mean = 443 ± 1 nm (SE), abaxial mean = 442 ± 1 nm), while about a third also had a well-defined green emission peak (range = 510-550 nm; adaxial mean = 523 ± 1 nm, abaxial mean = 524 ± 1 nm) and one species also had a yellow emission peak at 568 nm. Fluorescence excitation peaks ranged from 285-370 nm (mean adaxial excitation peak = 342 ± 1 nm and mean abaxial excitation peak = 341 ± 1 nm) among surveyed species. There was a significant positive correlation between adaxial and abaxial excitation peak wavelengths (r = 0.66), as well as between adaxial and abaxial emission peak wavelengths (r = 0.97). To quantify and compare emission peak intensities among species we determined a fluorescence yield index (FYI) calculated as the emission peak energy divided by total incident excitation energy. The FYI varied over an order of magnitude among species. On average, grasses/sedges and succulents had significantly greater FYIs than the other five life forms. The FYI of blue (<500 nm) adaxial emission was strongly correlated (r = 0.76) with abaxial emission. Our findings suggest BGF may be caused by several compounds in addition to cell-wall-bound ferulic acid which can vary among species but appear to be similar on adaxial and abaxial foliage surfaces within a species. The large range in FYI suggests some species may possess considerably greater amounts of BGF compounds than others.
KW - Blue-green fluorescence
KW - Fluorescence emission spectra
KW - Fluorescence excitation spectra
KW - Ultraviolet radiation
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U2 - 10.1016/S0176-1617(00)80313-2
DO - 10.1016/S0176-1617(00)80313-2
M3 - Article
AN - SCOPUS:0034100409
SN - 0176-1617
VL - 156
SP - 242
EP - 252
JO - Journal of Plant Physiology
JF - Journal of Plant Physiology
IS - 2
ER -