Recovery of the resurrection plant Craterostigma wilmsii from desiccation:: protection versus repair

Craterostigma wilmsii Engl. (homoiochlorophyllous) is a resurrection species that is thought to rely primarily on the protection of cellular components during drying to survive desiccation. The time taken for this protection to be instituted is thought to preclude recovery after rapid drying. Thus the response of C. wilmsii plants to rapid dehydration was investigated. The effect of rapid drying on sucrose accumulation was determined and the cellular ultrastructure was investigated during natural (slow) and rapid dehydration and on subsequent rehydration. The dependence of naturally and rapidly dried C. wilmsii on de novo transcription and translation during and after rehydration was determined by examining quantum efficiency, changes in photosynthetic pigments and subcellular organization of excised leaves with rehydration in water and using the metabolic inhibitors, distamycin A and cycloheximide. Slowly dried C. wilmsii required no new transcription or translation during rehydration in order to recover. With rapid dehydration, cells showed ultrastructural damage, which indicated that at least some protective mechanisms were affected (as evidenced by a reduced accumulation of sucrose). C. wilmsii was able to limit the damage and recover upon rehydration in water, but rapidly dried plants did not survive if mRNA or protein synthesis was inhibited by distamycin A or cycloheximide, respectively. This demonstrates an induction of repair mechanisms during rehydration, which enables recovery from rapid drying. Thus, although C. wilmsii does rely almost entirely on protection during natural drying, it apparently has the ability to repair if protection is inadequate and damage is incurred.