PT  - JOURNAL ARTICLE
AU  - Gorton, H. L.
AU  - Vogelmann, T. C.
TI  - Effects of Epidermal Cell Shape and Pigmentation on Optical Properties of Antirrhinum Petals at Visible and Ultraviolet Wavelengths
AID  - 10.1104/pp.112.3.879
DP  - 1996 Nov 01
TA  - Plant Physiology
PG  - 879--888
VI  - 112
IP  - 3
4099  - http://www.plantphysiol.org/content/112/3/879.short
4100  - http://www.plantphysiol.org/content/112/3/879.full
SO  - Plant Physiol.1996 Nov 01; 112
AB  - We used the Mixta+ and mixta- lines of Antirrhinum majus as a model system to investigate the effects of epidermal cell shape and pigmentation on tissue optical properties in the visible and ultraviolet (UV) spectral regions. Adaxial epidermal cells of Mixta+ flowers have a conical-papillate shape; in the mixta- line the cells are slightly domed. Mixta+ cells contained significantly more anthocyanin and other flavonoids than mixta- cells when plants were grown under either high- or low-UV conditions. Mixta+ cells focused light (3.5–4.7 times incident) within their pigmented interiors, whereas mixta- cells focused light (2.1–2.7 times incident) in the unpigmented mesophyll. UV light penetrated the epidermis (commonly 20–50% transmittance at 312 nm) mainly through the unpigmented peripheral regions of the cells that were similar for the two lines, so that overall penetration through Mixta+ and mixta- epidermises was equal. However, maximum UV absorption in the central region of epidermal cells was slightly greater in Mixta+ than mixta-, and intact Mixta+ flowers reflected less light in the spectral regions with intermediate flavonoid absorbance. In both cases, about 50 to 75% of the difference could be attributed to cell shape and resulting changes in the optical pathlength or focusing.