• 57. What Did the First Flower Smell Like?
Darwin worried about when and where flowering plants first appeared. In the intervening 150 years, researchers have tried—and failed—to answer that question. But last May, paleobotanists at the Florida Museum of Natural History and at Jilin University in Changchun, China, announced fossil remains of "probably the most complete, oldest flowering plant in the world," says David Dilcher, a scientist who analyzed the 125-million-year-old fossils. The age of the plant, unearthed from a lake bed in China, is less startling than its appearance. Dogma in the field maintains that angiosperms, as flowering plants are called, evolved from shrubs that resembled modern magnolia trees. Yet Archaefructus sinensis is a small, fleshy, aquatic plant that looks more like an herb than a flowering tree. It has the reproductive organs of a flower but no brightly colored petals.
— Rabiya S. Tuma
• 67. Plants That Don't Wilt
In March a team of researchers working in England and the Czech Republic announced the creation of plants that stay green and lush for more than seven months after being cut and placed in water. Peter Meyer, a molecular biologist at the University of Leeds, and his colleagues identified a gene they labeled Sho (for shooting), which controls production of cytokinins, hormones that delay aging in plants.
The control tobacco plant (left) is a 58-day-old cutting. The same type of tobacco plant (right), engineered in the experiment to express the Sho gene, is also 58 days old.
Courtesy of Elena Zubko and Peter Meyer/ University of Leeds.
The team modified Sho to boost cytokinin production and inserted it into potatoes, petunias, and other floral species. "We assume cytokinins are made mainly in the roots of a normal plant, so when you chop off its roots, the plant has lost its supply," says Meyer. "Because these genetically modified plants have cytokinin everywhere and keep producing it, they live on and produce roots when a normal plant would just die."
Increased levels of cytokinins also bolster plant resistance to disease and could prolong the shelf life of crops—which, Meyer believes, could help people in less-developed countries. "We do produce sufficient food," he says, "but we're wasting a lot on the transport."
— Lauren Gravitz
RELATED WEB SITES:
"What Did the First Flower Smell Like?" Learn more about the oldest flowering plant at the Web site of the Florida Museum of Natural History: www.flmnh.ufl.edu.