The derivative absorption spectra of chlorophyll in algae and leaves at low temperatures

Abstract

Chlorophyll a in live plants is found in several spectroscopically distinct combinations which are difficult to recognize because their absorption bands strongly overlap. These spectral bands can be distinguished, however, through derivative spectrophotometry, especially at low temperatures which sharpens the bands and makes possible the detection of smaller amounts of minor components than is possible with measurements at room temperature. The derivative absorption spectra of a number of algae and leaves were measured at room temperature and at about — 180°. For example, at low temperature, in the spectra of Porphyridium cruentum, Phormidium persicinum, and lettuce leaf, a shoulder appeared with maximum probably near 655 mμ which belonged to an unidentified component.