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Why Study Plants

by Sarah E. Wyatt, Ph.D.

Typically, when people think of science they think of animals, not plants. However, there are over 800,000 species of plants on Earth. The plant cell wall is the most abundant organic material on Earth; and RUBISCO, the first enzyme involved in carbon fixation, is the most abundant protein. Plants are an integral part of our daily life. They provide oxygen, food, and shelter as well as a variety of other products we use on a daily basis.

Plants are truly amazing organisms. They have adapted to the most severe climatic conditions on Earth: desert, underwater, salt water, extremes in light, altitude, cold, and heat. And although non-mobile, they have developed methods to avoid predation and to attract insects for pollination.

Still, there seems an overwhelming bias in science toward animals. Science, however, had its origin in plant science and began as an attempt to increase food supplies and develop medicines. There is evidence for organized agriculture as early as 8000 - 10,000 B.C. Plant science as a discipline existed in ancient Greece. As in even older cultures, the study of plants started when the early Greeks developed a practical interest in food and drug plants, but they slowly became curious as well about the structure and function of plants. One of the these Greek herbal physicians had a son who became one of the most renowned philosophers of all time-- Aristotle. Although better known for his philosophical works, Aristotle acquired extensive knowledge in nearly all aspects of natural history. In the mid 300 B.C., he founded a botanical garden in Athens. This is the oldest botanical garden of which any record remains. Upon his death, he willed the botanical garden and its associated library to his pupil and assistant, Theophrastus of Eresus. So great were Theophrastus's contributions to botany as a science that many consider him the "Father of Botany."

By the 2nd century A.D., the number of herbalists, as they were called, mushroomed, and the period from about 1500-1700 A.D. became known as the Age of Herbals. The herbalists were mostly concerned with medicinal plants which they studied in the botanical gardens that had become numerous and extensive in Europe by this time. They produced elaborate and intriguing illustrations occasionally accompanied by outlandish stories and descriptions. It was this interest in plants for medicinal benefits that led to the medicinal sciences.

Several other scientific disciplines also owe their beginnings to the study of plants. In 1665 the English physicist, Robert Hooke first saw "little boxes" in thin slices of cork. He called the little boxes cells. These cells were actually the cell walls of the woody tissue. He also saw the "juices" of living cells of elderberry plants, thus laying the groundwork for cell biology.

The 1800s saw an explosion of science, and plant science led the way. It was during this time that the cell theory was formalized with the discovery of the nucleus by the English botanist Robert Brown and the discovery of the nucleolus by the German botanist Matt Schleiden. Also in the 1800s, genetics, the study of heredity, was founded by the Austrian monk Gregor Mendel. His classic experiments with pea plants laid the foundation for all future work in genetics. With the Irish Potato Famine of the 1840s, botanists were the first to realize that microorganisms cause disease (predating Pasteurs' work with yeast by two decades). No longer was disease attributed to magical forces but to the biological activity of tiny parasites.

These accomplishments have continued into the 20th century. The first virus was isolated and purified from tobacco. The relationship between chromosomes and genes and the discovery of transposable elements or "jumping genes" occurred in plants, and these are but a few of the accomplishments of plant scientists.

The Potato Famine also illustrates how plants have had a profound affect on politics, culture and society. Not only did the famine worsen relationships between the Irish and English, but it led to the death of 1 million Irish men, women and children, the immigration of another 1.5 million, and a total upheaval of the socio-economic structure in the land.

Another, less devastating, example of the effect of plants on culture is the British custom of drinking tea. By the 1600s coffee houses were the major social centers in England. The Dutch were the first major European coffee importers, transporting coffee from their colonial plantations in Ceylon (now Sri Lanka). During Napoleon's time, much of this coffee-producing area was lost to the English. In 1825, the British began development of their property in Ceylon, and every suitable piece of land was planted to coffee. By the mid 1800s Ceylon was the world's greatest coffee producer. Today, however, 90 percent of the world's coffee is produced in the Western Hemisphere. Ceylon is best known for its tea production, and tea has become a familiar part of England's culture. All of this because of a plant disease, coffee rust.

The coffee rust fungus reached Ceylon by 1875. Within 20 years, 400,000 acres of coffee plantations were devastated and coffee production had essentially ceased. The British government made several attempts to save the coffee industry but was unsuccessful. It finally decided to replace the dead coffee trees with tea bushes. Luckily no fungus invaded the tea crop. In an attempt to escape the rust disease, coffee production moved to the Western Hemisphere where the pathogen was not present. Today, coffee production is a major economic factor in Central and South America, and the world coffee market is dominated by Brazil and Colombia.

Yet the effect of plants on our lives is even more fundamental. Plants are capable of transforming the Sun's energy into energy forms usable not only to themselves but also to animals and humans. They are truly at the bottom of the food chain. Nothing we eat has not at some time come from a plant. They are so interwoven into our lives that we often take them for granted. And not just for food and drink! Wood for houses, for heat, paper, cardboard, fabrics, rubber, spices, perfumes, dyes, adhesives, emulsifiers, medicines, even fossil fuels were once plants or dependent on them, not to mention the aesthetic value of plants. Try to imagine your life without plants or plant products. Even if we could discover another source of food and other products, without plants on Earth it is estimated that we would suffocate within 11 years. Plants are the quintessential carbon dioxide scrubbers and provide virtually all the oxygen we breath.

It's not surprising that as man moved out into space, plants would need to follow, especially to provide the "closed system" necessary for long-term space flight. Now the question became: could plants grow in space? Space was an ecosystem they had not encountered. The biggest question of course was gravity or lack thereof. Nutrients and light could be provided. The last great unknown, gravity, was so taken for granted on Earth that it was not even considered a variable in experimentation.

But in 1961, Yuri Gagarin cracked the door to space flight and new possibilities for mankind, including microgravity. Twenty days later, Alan Shepard followed Gagarin into space and propped the door open for all time. Gravity became a variable! Almost 40 years later we still know very little about how plants respond to microgravity. Although we've learned a great deal, a quote from Robert Fulgham's book All I Really Need to Know I Learned in Kindergarten still rings true and spurs the imagination of children and scientists alike: "Be aware of wonder! Remember the seed in the Styrofoam cup: the roots go down and the plant goes up and nobody really knows how or why."

Sarah E. Wyatt, Ph.D.
Research Associate, NSCORT
Department of Botany, Box 7612
North Carolina State University
Raleigh, NC


 
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