Protein Synthesis and Photosynthetic Recovery in the Resurrection Plant, Selaginella lepidophylla

Abstract

The effects of inhibition of protein synthesis on whole-plant CO2 exchange and on protein synthesis during hydration of the resurrection [poikilohydric] plant S. lepidophylla (Hook and Grev.) were examined. Chloramphenicol and cycloheximide inhibited the redevelopment of photosynthetic capacity which normally occurs within 24 h of hydration in the light. The inhibitory effect of chloramphenicol was greater than that of cycloheximide. The onset of chloramphenicol inhibition of net photosynthesis occurred only after 12 h of hydration. Cycloheximide stimulated net CO2 influx early after rehydration and inhibited net CO2 influx after 14 h of hydration. Total protein synthesis, as measured by L-[35S]methionine incorporation, increased through 24 h of hydration. Most protein synthesis within the 1st 12 h of hydration was cytoplasm-directed, whereas the rate of organelle-directed protein synthesis remained low until 12 h of hydration and increased rapidly thereafter. Apparently, organelle- and cytoplasm-directed protein synthesis are necessary for full photosynthetic recovery during rehydration of S. lepidophylla.