RHYTHMIC REGULATION OF THE LIGHT‐HARVESTING CHLOROPHYLL alb PROTEIN and THE SMALL SUBUNIT OF RIBULOSE‐1,5‐BISPHOSPHATE CARBOXYLASE mRNA IN RYE SEEDLINGS

Abstract

In etiolated rye seedlings transferred to light the expression of chlorophyll a/b binding protein mRNA varies when the seedlings are grown in a day/night cycle. The fluctuation pattern follows a circadian rhythm. Exposure of 4-day old etiolated seedlings to continuous white light revealed two maxima within the first 24 h before the 24 h cycle period appeared. These first two maxima are also observable after a pulse of white light or after a pulse of red light. These results indicate a possible involvement of phytochrome in the endogenous regulation of the rhythm.