Premières données sur l'activité photosynthétique de quelques algues subaériennes vivant en milieux très peu éclairés

Abstract

The photosynthetic activity of three sciaphilous algae (including two cavernicolous ones) was measured with a Clark electrode in the air, by light minus dark differences in the rates of [Formula: see text] under laboratory and near natural physical conditions. Photosynthesis versus light intensity curves showed a sharp slope at low light and a suddenly lower slope at medium intensities; this is interpretable as the Kok effect. This phenomenon is stronger with cavernicolous algae than with less sciaphilous plants. High yield activity of the three studied algae was observed only in the naturally encountered range of light intensity. A seasonal adaptation of light activity was shown but not a daily one.