Characterization of Protein Synthetic Changes in a Desiccation-Tolerant Fern,Polypodium virginianum. Comparison of the Effects of Drying, Rehydration and Abscisic Acid

Abstract

The desiccation-tolerant fern, Polypodium virginianum, was able to lose more than 60% of its fresh weight during periods of prolonged water stress and fully recover during periods of water availability. Rehydration from the air-dry state occurred rapidly (within 24 h) with a concurrent initiation of protein synthesis. A low-molecular-weight doublet was synthesized during water stress and was stable for at least 24 h after rehydration. These proteins were expressed also when the fully hydrated fronds were subjected to exogenous ABA even though drying resulted in a 10-fold reduction in ABA content. The large subunit of Rubisco was synthesized during drying, but despite temporary accumulation, the de novo synthesized component was degraded during rehydration