Capturing Solar Energy

Eco-Farm: An Acres U.S.A. Primer — Lesson 2: The Forgiveness of Nature, Part 3

This is an excerpt from Charles Walters’ Eco-Farm — An Acres U.S.A. Primer , available from the Acres U.S.A. bookstore at bookstore.acresusa.com . Read more excerpts from this book using the category “Eco-Farm” ( https://members.acresusa.com/magazine-features/eco-farm/ ).

9. Plants capture solar energy

All energy comes from the sun. Tiny spines called trichomes probably focus the sun’s energy onto the surface of the leaf. The curved trichomes on small veins of wild grape leaves, for instance, are hollow. They are also coated with wax exactly as are the sensilla spines on insect antennae—a happenstance we will discuss in the lesson on insects. Likely, the leaf trichomes should be credited with the efficiency mentioned earlier, that of plants needing only one part in 2,000 of the sun’s energy for efficient growth.

In any case, plants capture solar energy in their leaves, as we have seen in lesson 1, and use this energy to make sugar. They then go out to construct cells of all kinds, using sugar, air, water and earth minerals as building blocks. The first part of the equation is the photosynthesis story everyone from van Helmont to Van Niel has spent so much time unraveling—the business of plants using sunlight to synthesize a new substance, namely sugar. After that, sugar and oxygen serve up carbon dioxide, water and energy. From a chair of a theory of energy, chlorophyll (the green coloring matter of vegetation that is built around a single atom of magnesium) is the original capitalist. Energy capital is there for the taking. Plants always have been and always will be the chief key to natural energy because the chlorophyll is the principal transformer of solar energy into the kind of power plants, animals and human beings can use.

Plant leaves thus manufacture plant food. They store food, run a refrigeration device for the plant, and do the plant’s breathing. Knowing this much, scientists kicked open the door to even more knowledge during the 1950s. Sylvan H. Wittwer, Ph.D., of Michigan State University found that the efficiency of foliar fertilizers was 100 to 800% greater than fertilization with dry materials applied to the soil. The results of this pioneer research were made a matter of record in an audio film styled The Non-Root Feeding of Plants.

Stems, too, have a character and nomenclature all their own.

10. At the terminal bud

Growth takes place at the terminal bud. If the terminal is pruned away, the next bud in the pecking order takes its place and becomes the leader. Many dicot plants—but not all—have lateral branches or suckers. Some have a bud that can give shots that ultimately carry flowers and fruit on the side of the stem.

As noted earlier, root eyes appear on many plants. It is from these eyes that adventitious roots grow to supply prop roots, such as one sees in a corn field.

Another distinguishing feature that separates dicots from monocots should be noted.

Taking a cross section of each stem, it will be seen that dicots have clear rings, a cambium layer, bark and a distinguishing core. The monocots seem to have vascular bundles scattered more or less at random. Dicots such as the sweet potato, soybeans, and rhubarb are usually woody. Monocots such as corn and asparagus are soft and fibrous.

The cambium layer is simply growing tissue. It grows wood and veins inside and pushes the bark out. This process continues year after year, hence the growth ring. Cut the cambium layer, and it will heal, leaving a scar. This is the reason naval stores—made into rosin, pitch and turpentine—are tapped without going through the cambium layer, otherwise the tree trunk would become a mass of scars.

The monocot stem is quite different. There are no cambium growth rings, just the fibrous materials running vertically through the flesh of internodes. There are the vascular bundles mentioned earlier. Here is the plumbing system that carries plant food and water from soil to leaves, and sometimes water from leaves to the soil.

The dicots have veins in the growth ring. The cambium is creating new tissue constantly. In monocots, veins are run like network through the entire stem. The stem grows bigger as old tissues swell and become vascular bundles and also expand.

11. Rhizomes

Stems can be the source of new plants as cuttings are taken, or runners reach out for a new anchor. Some plants—Bermuda, for instance—have underground stems called rhizomes. These send out roots from some of their nodes. The sweet potato does the same, as does the watermelon plant. A grape plant can be trained to re-root in exactly the same way.

12. Non-root feeding

As suggested by Non-Root Feeding of Plants experiments, some plants absorb dust particles from the air to obtain minerals. Some plants—like pepper plants—send out roots that attach themselves to soil and other plants, but they obtain no food or moisture this way. They simply catch and hold rain and dew with their foliage. Such plants are styled epiphytes.

Flowering plants are of main concern to the farmer since most commercial production—leather ferns and mushrooms excepted—have to do with sexual reproduction, pollination, and the man-directed experiments called hybridization.

13. Sex in plants

The Arabs were the first to recognize male and female sex in plants. They realized that boy trees had to be planted with girl trees or there would be no date crops. Still it remained for an Austrian monk to put plant sex studies on a scientific basis.

Gregor Johann Mendel entered the order of Augustinians at Bruim in 1843, age 21. In the monastery garden he grew peas—tall with dwarf, yellow seed with green seed, whatever—making all the combinations ingenuity and logic could account for. Some 22 years later Mendel read his famous paper on genetics before the Natural History Society at Brunn. Needless to say, those who heard Father Mendel’s epoch making work on how peas transmit their traits failed to comprehend Mendel’s Law, or the new world of knowledge it had opened to them.

Mendel directed attention to the plant flower.

As noted above, the cut of floral leaves is called the calyx. Each of the individual leaves is called a sepal. These are sometimes joined together. Sometimes they are not. In the middle of any flower is the style, and further down, the ovary. Ovary, style and stigma are called pistil. Note that the pollen sacs attach at the ovary and shoot out and up, reaching almost to the stigma. The pistil is the female part of the flower. The pollen sacs are the male part.

A sweet nectar characterizes many flowers, as does a pleasant perfume. These pheromones are simple molecules featuring eight or ten carbon atoms in a chain, but they telegraph messages that put ITT to shame. They program the bees and insects, telling them to come or stay away, hand out instructions on how to behave toward the opposite sex, and how to help the flower in its birth-oriented program. Bees move about, gathering and coming, testing and going, all to feed their own young and obey the in junction to increase and multiply. As they move and fly, they distribute the pollen to the stigma—pollination!