A recently uncovered, perfectly preserved, 400-year-old plant specimen might be the answer to our increasingly important colonisation of other planets — and the preservation of the human race as a whole. You probably already know that human stem cells hold a vast, wildly exciting potential — both in terms of furthering our understanding of the human body and in saving countless lives.
But did you know plants have their very own version of the industrious little cells, called bryophytes, that could prove just as important in saving humanity? That's exactly what scientists have found and what's gotten them so excited.
Lead by Catherine La Farge, a team of researchers from the University of Alberta was exploring mosses around the Teardrop Glacier in the Canadian arctic archipelago when they discovered that portions of the (now rapidly receding) glacier were tinted an incongruous green. After taking the sample plant material back to her lab, the team ground up the specimens, placed them in potting soil, and watched with awe as they successfully regenerated from their 400-year-old parent material.
As the glacier recedes at an astonishing rate of 3m-4m per year since 2004, scientists have gained access to an increasing amount of centuries-old plant life frozen in time. Every discovery up until now, though, has been flora of the vascular variety. But it's this non-vascular sort that, though often overlooked, holds the key to understanding our past and our future.
What's a Bryophyte?
Vascular plants are primarily defined by the existence of a xylem and a phloem, or in other words, the parts that suck up water and nutrients and send them shooting throughout the rest of the plant. Non-vascular plants, as all you keen observers may have already guessed, don't have this system — they're a far more simple breed. Made to freeze and dry out, they're able to survive in conditions that vascular plants, what with their fancy leaf and stem tissue needing "water" and "food" all the time, could only dream of.
Bryophytes, which fall into this latter category, have to reproduce asexually since they often don't have access to water, which is key to fertilization. And because of this, depending on its environment, a single bryophyte cell can essentially reprogram itself to grow as an entirely different plant. But that's not even the exciting part. As La Farge explained:
This has been known forever by biologists who deal with bryophytes. Because if a moose goes through a forest, it might pick up moss in its toes and carry that material somewhere else. So when the plant tissue drops, it will be able to reestablish itself in its new environment and thrive.
It's as if you could drop a lion in the ocean and have it grow gills.
So... What's the Big Deal?
As glaciers retreat and a greater variety of plant life surfaces, it's essentially like peeling a blanket back over a perfectly preserved portion of the past. Dormant, yes — but alive nonetheless. And that's what makes this discovery so incredible. The knowledge that it's even possible for plant life to survive in such extreme conditions opens the door to a deeper understanding of this robust group's cell biology. Which in turn, could very well pave the way towards us figuring out how the hell we're going to grow plants on other planets — oh, say Mars, for instance.
Because unquestionably, before we can even begin to fantasize about sending people into the red abyss, we're going to need to test whether or not plants can survive in those kinds of conditions — harsh light, dryness, freezing, etc. And now it seems like we may have found just the plant for the job. Eschews water? Check. Ability to reproduce simply and all by its lonesome? Check. Doesn't mind the cold? Double check. Not to mention the fact that it can morph into other plants.
Which is part of the reason why bryophytes represent the second largest lineage of land plants in terms of diversity — 10,000 different species diverse, to be exact. And various, disparate strains will happily live side-by-side; they don't compete in the way vascular plants do. Rather, they bunch as close together as possible, which allows them to retain the moisture that facilitates their entire biological life cycle. So there's a reason you'll always see moss growing in tufts. And though they might be virtually microscopic as single organisms, there's still plenty about them to find fascinating — especially if you're a bryophyte enthusiast like La Farge. As she explained to us:
It's mind boggling, because normally you walk through a forest, and you see green moss on a rock. So you might think oh, that's a nice moss and move on. But you never stop to think about what that green actually represents. How diverse is it? How many species are we really considering here? I mean, when you're up in the high arctic, if you pick up just a small packet, say a letter envelope size, you can often get 15 different species of bryophytes in one letter-size collection. It's pretty amazing.
The Next Stage
There's still many other organisms that could be lying peacefully under the still-frozen glacier. Scientists knew that fungi, yeast, and bacteria were all able to survive in ice, and they also knew that both vascular plants and mosses could live on the top of a glacier. But this is the first time we've really considered the possibility that the stuff peeking out from underneath the glacier just might be alive. Frozen specimens, then, won't necessarily be considered dead on arrival, leaving researchers with plenty of work ahead of them.
La Farge is particularly interested in moving into the lower latitudes, where the even more rapidly shrinking icecaps are exposing even older glimpses of past life. And all of this will only enhance our newly illuminated understanding of basic life systems — something we're going to need when we start planting biodomes on other planets.
Of course, tests like that may still be quite a ways off. But at least now, we have plenty of reason to hope. [Proceedings of the National Academy of Sciences of the United States]
Pictures: Catherine La Farge