Sunday, August 17, 2014

Resurrection Fern

At the bottom are two fronds (under clear contact paper) showing variability.


Resurrection Fern
Polypodium polypodioides

This tiny fern has always been a favorite of mine.  It grows in an epiphytic fashion, anchoring its wiry roots into the bark of trees with deep fissures, and receiving nourishment from the water and dust in the atmosphere using energy from the sun via photosynthesis.  The fronds of this fern are fairly small, but I’ve seen some that grow up to 3 or 4 inches. 

It’s called the resurrection fern because it has an adaptation that allows it to transform from a withered brown cluster of curled leaves to a vibrant unfurled green frond.  This adaptation allows it to survive long periods of drought until the rains come, which is helpful in south Florida, with our dry fall-winter-spring and our rainy summers.  Scientists tell us that resurrection fern can stand up to a 95% water loss without perishing.  Compare that to humans, who often find a 15% water loss a fatal event.

The curled, dry fronds, waiting for water.
I learned that this feat is possible because of a protein called dehydrin.  Dehydrin allows the cell walls in the leaf to fold when drying, in a way that can be reversed without damage.  As the fern dries, it manufactures dehydrin, turns brown, and stops photosynthesis.  When moisture is available, the fern takes water in through its stomata (tiny openings on the bottoms of leaves that allow for gas exchange), turns green, and begins photosynthesis once again. 

I’d always thought of it as native to tropical Florida.  Imagine my surprise to find out that these ferns range from Florida to Delaware and then west to Texas!  Not only is it native to the Americas, but it’s also native to Africa.  

A complex ecosystem in a small space.
This ink and watercolor study is of a live oak branch that fell to the ground after a rainstorm.  The branch broke into several smallish chunks, so perhaps it was insect-damaged; my experience with oaks is that the wood is very strong.  I loved the interplay of texture and colors in this tiny universe of lichens, mosses, bark and fern.  Once again, sketching a subject led me to ask questions and then to start
researching.

Needless to say, scientists are studying the property of dehydrins, which could have many applications.  Did you know that resurrection fern has gone into space?  It was the subject of a 1997 experiment on board the space shuttle Discovery.  To read more about this fascinating plant, visit the hyperlinks within the text or listed below.

As always, thanks for visiting!

The sketch was done in my:
Aquabee Super Deluxe  spiral-bound sketchbook
9x6 in, (22.86 x 15.24 cm), 93 lb. paper
Sakura Micron Pigma pen 01,
Daniel Smith watercolors.

Resources:
Wikipedia on resurrection fern 
Time lapse YouTube video of resurrection fern coming back to life
Wikipedia on dehydrin