The selective photochemical action of polarised light.—I. The hydrolysis of starch

Abstract

In some experiments carried out during the summer of 1921, on the effect of different kinds of light on the growth of plants, it was found that plane-polarised light causes a marked acceleration in seed germination and in the formation of flowers, but that no effect was noticed on the vegetative growth of the stem and leaves. Since the first two processes involve a hydrolysis of reserve food material, some experiments have been carried out on the hydrolysis of starch in heterogeneous light, and in plane-polarised light, in order to determine whether any selective action of the latter can be observed in vitro . In this connection it is interesting to note that in the living leaf the starch synthesised during the day undergoes hydrolysis to sugars in the early evening, when, as is well known, the light from the sky is polarised. The results obtained would seem to show that plane-polarised light exerts very definitely a selective photochemical effect compared with ordinary light. Two series of experiments on the photochemical hydrolysis of starch have been carried out, one with daylight and the other with artificial light from an ordinary Osram filament lamp. In both series carefully purified starch grains were mounted on microscope slides in the presence of weak enzyme solution.