Effects of leaf color and the light quality applied to leaf-developing period on the photosynthetic response spectra in crop plants

Abstract

Photosynthetic action and quantum yield spectra and the absorptance spectrum were determined for crop plant leaves with different degrees of greenness, for the purple leaves and for the leaves developed under different light qualities, to determine the variable range of the spectral responses as affected by the leaf color and growth conditions of plants. The action relative to the red peak was lower for pale-green leaves than for deep-green ones in the waveband 500-650 nm for all 7 species tested. A negative correlation was found between the ratio of action at 435 nm to that at 560 nm and the absorptance at 560 nm in the leted by the leaf color and growth conditions of plants. The action relative to the red peak was lower for pale-green leaves than for deep-green ones in the waveband 500-650 nm for all 7 species tested. A negative correlation was found between the ratio of action at 435 nm to that at 560 nm and the absorptance at 560 nm in the leaves with different degrees of greenness. Purple leaves of flowering kale and perilla had a high absorptance in the green region unlike those of green leaves, and characterized by a large drop in this region either in the action or quantum yield spectrum. Rice leaves developed under blue, red and neutral plastic covering showed a little difference in the relative action at around 600 nm, tut no clear difference among them either in the absorptance or quantum yield spectrum. These facts suggest that the spectral responses of photosynthesis vary with the leaf characteristics especially with the difference in color, whereas the variable range may not be greater than that of the responses observed among species except for leaves with special colors such as purple. The author wishes to thank Dr. N. Katsura of this laboratory for his helpful discussions, and Dr. A. Amemiya and Dr. H. Saka of this Institute for supplying the seeds of rice mutant, CMV-44. © 1977, CROP SCIENCE SOCIETY OF JAPAN. All rights reserved.