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Smart Plants Plants do some very clever things, scientists say People don't usually associate intelligence with weeds or cabbages. But plant scientists, taking advantage of new genetic information, have discovered a surprising level of what looks like brainy behavior in the vegetable world. Plants have to do clever things since they are stuck in place, and must find ways to cope with enemies and hard times. To compensate for their immobility, plants have genes that direct them to perform some remarkable feats. Though plant behavior may seem obvious to farmers and gardeners, only recently have biologists begun learning exactly how plants work, down at the level of individual genes and molecules. Brainy behavior Researchers have identified genes that help plants recognize when days are growing longer or shorter, Other genes force a plant to sit through a cold winter before allowing it to blossom. Another maintains a 24-hour internal clock. Some genes help plants "remember" the experiences of their "parents," the plants whose seeds gave them birth, said plant geneticist Johanna Schmitt. Plants use color and smell to lure insects that spread their pollen, or to repel hungry predators. Plants aren't above using dirty tricks, such as attracting wasps to lay their eggs inside caterpillar larvae. These larvae hatch from moth eggs laid on the plants. The wasps kill the larvae, preventing the growth of caterpillars that would eat the plants. Some plants can solve math and logic problems—of a sort. They calculate the ratio of two different hues of red light to decide when there's too much shade and they need to grow taller. When roots sense that water is short, a gene called BYPASS1 sends a signal to the stem telling it to produce fewer, smaller leaves to minimize evaporation through its leaves. Practical application Researchers expect their work will have practical value for farmers and home gardeners. Judith Roe, a plant geneticist at Kansas State University, said understanding how plants synchronize their flowering with the state of the environment will help researchers predict and manage the effect of climate change on future crops. "In flowering plants, the time of flowering is probably the most critical period in their life cycle," Roe said. "At this point, they are particularly vulnerable to environ mental stresses." To figure out how plant genes work, the National Science Foundation awarded a $5 million research grant to an international team of scientists headed by Schmitt The team's task is to identify the molecular mechanisms by which plants know when to grow and when to flower—two distinct stages of vegetable life that must be kept apart. A gene called FRIGIDA, for example, prevents plants from flowering prematurely, before winter has passed. "If the gene is faulty, it may flower too soon," Schmitt said. Genetic clues To make smart choices, plant genes must take in multiple cues from their environment- light, temperature, moisture, gravity, etc.—and assemble them into a meaningful whole. That's a rudimentary version of the way an animal's brain integrates various signals from its eyes, ears, feet and stomach. The messages that tell a plant it's time to blossom turn on several series of genes, called "pathways," which lead to other master genes controlling the roots, stems and leaves. Schmitt said scientists still don't understand how plants accomplish many of their clever tricks. "There are huge unanswered questions," she said. "That's what the National Science is Foundation project is all about."
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彭蒙惠英語

Smart Plants

Plants do some very clever things, scientists say

People don't usually associate intelligence with weeds or cabbages. But plant scientists, taking advantage of new genetic information, have discovered a surprising level of what looks like brainy behavior in the vegetable world.

Plants have to do clever things since they are stuck in place, and must find ways to cope with enemies and hard times. To compensate for their immobility, plants have genes that direct them to perform some remarkable feats. Though plant behavior may seem obvious to farmers and gardeners, only recently have biologists begun learning exactly how plants work, down at the level of individual genes and molecules.

Brainy behavior

Researchers have identified genes that help plants recognize when days are growing longer or shorter, Other genes force a plant to sit through a cold winter before allowing it to blossom. Another maintains a 24-hour internal clock. Some genes help plants "remember" the experiences of their "parents," the plants whose seeds gave them birth, said plant geneticist Johanna Schmitt.

Plants use color and smell to lure insects that spread their pollen, or to repel hungry predators. Plants aren't above using dirty tricks, such as attracting wasps to lay their eggs inside caterpillar larvae. These larvae hatch from moth eggs laid on the plants. The wasps kill the larvae, preventing the growth of caterpillars that would eat the plants.

Some plants can solve math and logic problems—of a sort. They calculate the ratio of two different hues of red light to decide when there's too much shade and they need to grow taller. When roots sense that water is short, a gene called BYPASS1 sends a signal to the stem telling it to produce fewer, smaller leaves to minimize evaporation through its leaves.

Practical application

Researchers expect their work will have practical value for farmers and home gardeners. Judith Roe, a plant geneticist at Kansas State University, said understanding how plants synchronize their flowering with the state of the environment will help researchers predict and manage the effect of climate change on future crops. "In flowering plants, the time of flowering is probably the most critical period in their life cycle," Roe said. "At this point, they are particularly vulnerable to environ mental stresses."

To figure out how plant genes work, the National Science Foundation awarded a $5 million research grant to an international team of scientists headed by Schmitt The team's task is to identify the molecular mechanisms by which plants know when to grow and when to flower—two distinct stages of vegetable life that must be kept apart.

A gene called FRIGIDA, for example, prevents plants from flowering prematurely, before winter has passed. "If the gene is faulty, it may flower too soon," Schmitt said.

Genetic clues

To make smart choices, plant genes must take in multiple cues from their environment- light, temperature, moisture, gravity, etc.—and assemble them into a meaningful whole. That's a rudimentary version of the way an animal's brain integrates various signals from its eyes, ears, feet and stomach. The messages that tell a plant it's time to blossom turn on several series of genes, called "pathways," which lead to other master genes controlling the roots, stems and leaves.

Schmitt said scientists still don't understand how plants accomplish many of their clever tricks. "There are huge unanswered questions," she said. "That's what the National Science is Foundation project is all about."

本網頁內容已獲空中英語教室授權，僅限台大人使用