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An Odyssey of Orchids at the United States Botanic Garden, Part 3
Temat: Środowisko
Do some Exercises: Słuchaj i zapisuj Tworzenie zdań Ukryte słowa
BARBARA KLEIN: It is illegal to collect orchids growing in nature. But poachers often do so. And orchids reproduce with difficulty. They depend on birds, bees or insects to spread their pollen to another orchid flower. Some orchids trick their pollinators. Such plants produce a smell that attracts pollinators not normally attracted to them. Other orchids trick male flies by making themselves look like female flies. Still others temporarily trap a pollinator. The action forces the insects to touch the orchid pollen. They pick it up on their bodies and carry it to another flower. Once the second flower is fertilized, seeds begin to form. Orchid seeds grow slowly. Sometimes they take months to develop inside the seedpods. The very small seedpods contain as many as three thousand seeds. The seeds float in the air when the pods break open. But they do not begin growing just anywhere. STEVE EMBER: The seeds need to be near what is called a mycorrhizal fungus. The seeds lack nutrients, and the fungus feeds them. But the fungus is rare, and some of its habitats are threatened. Thomas Mirenda is an orchid collection specialist at the Smithsonian Institution. Mister Mirenda says orchids growing in nature depend completely on their environment to survive. Human development or natural disasters can change that environment. The orchids cannot reproduce if birds and insects are no longer living in the area. He says loss of forests and climate change are part of the problem. Mister Mirenda also says very little money is available to help orchid conservation. He says financing is seriously endangered, like the orchids themselves. BARBARA KLEIN: Today, science and technology can produce orchids in large numbers in greenhouse settings. In nineteen seventeen, Cornell University scientist Lewis Knudsen found that under certain conditions, the fungus was not needed. He discovered that seeds or spores could grow if the seed could develop in a special preparation. The preparation had a sugar base and was similar to gelatin, a food product. The method was put into use a few years later in greenhouses. Seed germination in sterile nutrients is now a common way to reproduce orchids. STEVE EMBER: Mericloning also is a common modern method. The process calls for culturing from the merismatic tissue on a plant. Active growth takes place in that area. In the process, a small piece of tissue is taken from a high quality orchid. The tissue is made into tiny pieces and grown in a laboratory. Many exact copies of the orchid are produced. Whether grown naturally or through technology, people who love orchids say they are the most beautiful flowers on Earth. BARBARA KLEIN: This program was written by Jerilyn Watson . Our producer was Brianna Blake. I'm Barbara Klein. STEVE EMBER: And I'm Steve Ember. Source: Voice of America
