A requirement for cytoplasmic protein synthesis during chloroplast senescence in the aquatic plant anacharis canadensis

Cycloheximide (CHI) at 1 μg/liter delayed the loss of chlorophyll from detached Anacharis canadensis leaflets senescing in the dark. Chloramphenicol (CAP) and streptomycin (SM) slightly accelerated the loss. CHI was effective even during the later stages of senescence in preventing further loss of chlorophyll. Senescence proceeded normally upon return of the leaflets into water. The need for cytoplasmic protein synthesis during chloroplast senescence and the types of proteins involved are discussed.