Slow and Fast Desiccation of Single-cell Thick Fronds of Filmy Ferns

Materials and Reagents

1. Absorbent paper
   
2. Petri dishes (Merck, catalog number: CORM3160-150X15 )
   
3. Silica gel 2-5 mm (Merck, catalog number: 1077351000 )
   Note: Dry in an oven for 24 h at 60 °C.
4. Filmy fern fronds collected from Katalapi Park, Chile (Garcés et al., 2018).
   Note: Fully expanded fronds of about 20 cm long were used in this protocol.
5. Potassium chloride (KCl) (Merck, catalog number: 1049361000 )
   
6. Saturated KCl solution (see Recipes)
   

Equipment

1. Glass desiccator, amber 300 mm (W.W. Grainger, model: 5YHV5 )
   
2. Analytical scale (Sartorius, catalog number: BP221S )
   
3. Forced air drying oven 50 L (Biobase, catalog number: BOV-T50F )
   

Procedure

1. Wash the detached fronds from fully hydrated plants by soaking in distilled water for five minutes, remove excess water carefully by blotting with absorbent paper.
   
2. Place the fronds in a glass desiccator in the dark at room temperature, with 500 g silica gel (fast desiccation) or over 500 ml of a saturated solution of potassium chloride (KCl), 75% RH (slow desiccation) for 24 h.
   
3. Weight fronds every 10 min. Weight needs to be determined very rapidly.
   
4. For rehydration, place the previously desiccated fronds in Petri dishes with 10 ml distilled water in the dark for 24 h. Weight fronds every 10 min.
   

Recipes

1. Saturated KCl solution
   Dissolve 170 g of KCl to 500 ml distilled water
   

Acknowledgments

This protocol was adapted from previous work (Bewley and Oliver, 1992). This work was supported by grant #11130717 from FONDECYT.

Competing interests

The author declares no conflicts of interest or competing interests.

References

1. Bewley, J. D. and Oliver, M. J. (1992). Desiccation-tolerance in vegetative plant tissues and seeds: protein synthesis in relation to desiccation and potential role for protection and repair mechanisms. In: Water and Life: A comparative analysis of water Relationships and the organismic, cellular and molecular levels. In: Osmond, G. N. and Somero, C. B. (Eds.). Springer 141-160.
   
2. Dhindsa, R. S. (1987). Glutathione status and protein synthesis during drought and subsequent rehydration in Tortula ruralis. Plant Physiol 83(4): 816-819.
   
3. Garcés Cea, M., Claverol, S., Alvear Castillo, C., Rabert Pinilla, C. and Bravo Ramirez, L. (2014). Desiccation tolerance of Hymenophyllacea filmy ferns is mediated by constitutive and non-inducible cellular mechanisms. C R Biol 337(4): 235-243.
   
4. Garcés, M., Ulloa, M., Miranda, A. and Bravo, L. A. (2018). Physiological and ultrastructural characterisation of a desiccation-tolerant filmy fern, Hymenophyllum caudiculatum: Influence of translational regulation and ABA on recovery. Plant Biol (Stuttg) 20(2): 288-295.