Portal de Periódicos da CAPES

Interpretation of Light Quality Measurements and Plant Response in Spectral Filter Research

1992; American Society for Horticultural Science; Volume: 27; Issue: 11 Linguagem: Inglês

10.21273/hortsci.27.11.1208

2327-9834

Nihal C. Rajapakse, Robert Pollock, Margaret J. McMahon, John W. Kelly, Roy E. Young,

Remote Sensing in Agriculture

Experiments were conducted to correlate the response of chrysanthemum [Dendrathema ×grandiflorum (Ramat.) Kitamura] plants to light environment based on various quantitative light quality parameters by growing plants under 6% or 40% CuSO 4 and water spectral filters. Using a narrow band width (R = 655-665 and FR = 725-735 nm) or a broad band width (R = 600-700 and FR = 700-800 nm) for R: FR ratio calculation, 6% CuSO 4 filter transmitted light with a higher R: FR ratio than 40% CuSO 4 or water filters. Light transmitted through 40% CuSO 4 and water filters had similar narrow band R: FR ratios (≈1.2), but the broad band R: FR ratio (2.0) of 40% CuSO 4 filter was higher than that of water filters. The estimated phytochrome photoequilibrium (ϕ) value varied considerably with the photochemical properties of phytochrome used for estimations. Final height and internode length of plants grown in 6% or 40% CuSO 4 chambers was ≈30% less than of plants in corresponding control chambers. Leaf and stem dry weights were reduced by light transmitted through CuSO 4 filters. The results suggest that broad band R: FR ratio correlated more closely to above plant responses than the narrow band R: FR ratio. Blue (B): R and B: FR ratios (not absolute amount of blue wavelengths) correlated well with plant response, suggesting that involvement of blue light should not be ignored in expressing plant response to light transmitted through CuSO 4 filters. At present, the presentation of complete spectral data would be the most useful in explaining plant response to light environment.