The Dependence of the Quantum Yield of Chlorella Photosynthesis on Wave Lenghth of Light

Abstract

Measurements of the quantum yield of Chlorella photosynthesis have been made at different wave lengths of light, and compared with the estimated distribution of light absorption between the yellow and green pigment components. The estimation of light absorption by the pigments in the living cell was based on absorption curves for the extracted and separated components. The absorption characteristics of the pigments were found to be sufficiently altered by extraction so that the conclusions drawn from comparison of absorption and photosynthetic yield could lead to only tentative conclusions as to the activity of accessory pigments. The quantum yields were measured manometrically, on the basis of oxygen exchange. Preliminary measurements established that the dependence of yield on light intensity was the same for the red, green, and blue regions of the spectrum, at low light intensities. Wave lengths of light in the neighborhood of 480 mμ were found under certain conditions to cause large temporary changes ...