ENDOGENOUS AND PHOTOPERIODIC DIURNAL RHYTHMS OF IN VIVO LIGHT ABSORPTION AND SCATTERING IN THE GREEN ALGA ULVA LACTUCA L.

Techniques of in vivo spectroscopy were employed to demonstrate the presence of rhythms of light absorption and scattering in the green thalloid alga Ulva lactuca L. maintained in artificial nutrient medium under constant photoperiod. The absorbance during photophase at 682 nm, the chlorophyll a in vivo absorption maximum, was typically two to three times that during scotophase.