Saturday, June 9, 2012

Little Solar Panels

As the days get longer and the trees leaf out, spring ephemeral wildflowers race to soak in as much sunshine as possible. Spring beauties, wild leeks (ramps), Dutchman’s breeches, wood anemone, bloodroot, and trout lily are some of the most beautiful treasures of spring. They rush out of the ground each year, sometimes while snow still haunts the north-facing slopes. Flowers bloom, leaves unfurl, bees hum, ants crawl, seeds are set, photosynthesis produces sugars, starch is stored back into the roots, and then—just as the tree leaves above are reaching their full potential—the ephemeral leaves melt back into the duff.

Spring ephemeral wildflowers have figured out that they can make use of the rich soil in shady depths of deciduous forests, so long as they get a head start on the trees. Partly because they only show up for such a short time each spring, they have captured many a heart. They also capture many a photon.

Photons are little packets of energy that travel through space.  We know them as light. They carry energy from the Sun (released during nuclear fusion reactions) down to Earth. Once here, they provide almost all the energy for life on Earth. Plants, like these lovely spring ephemerals, are an essential link between the Sun and animals, since animals cannot capture sunlight on their own.

For just a few short weeks in spring, the flowers I mentioned above are absorbing photons like crazy, and using them to help split carbon dioxide from the air and water from the soil, and recombine those molecules into sugar.  Sugar is simply carbon, hydrogen, and oxygen.

This month, I am exploring the process of photosynthesis with first graders who come to the Museum for field trips. We act out a food chain starting with the Sun, and then shrink down so we can be magically transported into a leaf.  There we meet Chef Chlorophyll, the green pigment that mixes the ingredients of photosynthesis. The students race around the yard, gathering sunlight (yellow water), water (blue water), and air (drinking straws) to create a frothy green soup in the mixing bowl. Then we each eat a grape, and consider how plants produce the sugars that we eat every day in a hundred different forms.

The sugars produced by spring ephemerals are not distributed in sweet fruits, though. These plants mostly produce hard, dry seeds without the juicy cradle of flesh like apples and cherries. Instead, their precious sugars are stored as carbohydrates (complex sugars) in starchy roots. Burrow your finger into the soft soil near any of these plants, and you will soon pull out a small white tuber. The tubers of trout lilies and spring beauties have a mildly sweet flavor. Leek tubers store their sugar with an oniony kick. Dutchman’s breeches and bloodroots store their sugar with toxins added.

The spring ephemerals used the energy stored in these tubers to get a head start on the tree leaves this spring, and they are rushing to replenish their pantry for yet another year.

All summer long, other plants will be capturing the energy from photons of sunlight and storing it in their roots, stems, leaves, flowers, fruits and seeds. We harness that energy in a myriad of ways. Think about that as you eat you dinner salad, turn on the television, plant your garden, drive your car, and drink your morning coffee! Energy from the Sun is integral to every aspect of our lives. 

No comments:

Post a Comment