Emission spectra of luminous bacteria

Abstract

The relation between the rate of photosynthesis and the pigment content was studied in seedlings of Avena sativa var. Victory. Etiolated seedlings were illuminated during different periods. Next, the rate of photosynthesis as well as the pigment concentrations were determined in the primary leaves.

The saturation rate of photosynthesis proved to increase with increasing pigment concentrations until the ratio chlorophyl b / chlorophyll a approached its “normal” value. Although the amounts of both pigments still keep on increasing, the saturation rate of photosynthesis remains the same.

In agreement with other authors we could observe that the formation of chlorophyll a starts immediately upon illumination, while b is formed only after a lapse of time.

Xanthophylls are present in etiolated seedlings in relatively large amounts; their formation is not influenced by light.

Other carotenoids are also present in non-illuminated plants, though in small amounts. Light, however, accelerates their development.

As far as it was studied the quotient chlorophyll a / carotenes remains constant except for very low pigment concentrations.