Tripogon loliiformis elicits a rapid physiological and structural response to dehydration for desiccation tolerance

Resurrection plants can withstand extreme dehydration to an air-dry state and then recover upon receiving water. Tripogon loliiformis (F. Muell.) C. E. Hubb. is a largely uncharacterised native Australian desiccation-tolerant grass that resurrects from the desiccated state within 72 h. Using a combination of structural and physiological techniques the structural and physiological features that enable T. loliiformis to tolerate desiccation were investigated. These features include: (i) a myriad of structural changes such as leaf folding, cell wall folding and vacuole fragmentation that mitigate desiccation stress, (ii) potential role of sclerenchymatous tissue within leaf folding and radiation protection, (iii) retention of similar to 70% chlorophyll in the desiccated state, (iv) early response of photosynthesis to dehydration by 50% reduction and ceasing completely at 80 and 70% relative water content, respectively, (v) a sharp increase in electrolyte leakage during dehydration, and (vi) confirmation of membrane integrity throughout desiccation and rehydration. Taken together, these results demonstrate that T. loliiformis implements a range of structural and physiological mechanisms that minimise mechanical, oxidative and irradiation stress. These results provide powerful insights into tolerance mechanisms for potential utilisation in the enhancement of stress-tolerance in crop plants.