阅读理解
We usually think that plants always stay
quiet and never speak. Grass doesn't cry when you cut it; flowers don't shout
when they're picked. But this view of the world couldn't be more wrong. Plants
talk to each other all the time. Their language is one of chemicals.
Over the years, scientists have found that
different types of plants, from trees to tomatoes, send compounds(复合物)into the air to help
neighboring plants. But exactly how plants receive and act on many of these
signals is still a mystery.
Scientists from Kyoto University in Japan
looked at tomato plants that had been bitten by insects. To start out, they
grew plants in two plastic bags connected by a tube(管子). One plant had been bitten by
insects. The other was not bitten.
They found that when insects bite plant leaves,
the plants don't sit quietly. They send a chemical called "hexvic" into
the air. Humans can't notice it, but these chemicals carry a smell that
neighboring plants can notice. This way, neighboring plants realize the danger
and begin to give off more "hexvic" to protect themselves.
The same scientists continued their research
by placing insects on the plants that had not been bitten. The plants were able
to kill nearly 50 percent of the invaders,
much more than their neighbor.
It was surprising that the plants that had
not been bitten didn't send the chemical until the received a warning message
from their infested(受侵的)neighbor,
the scientists said. These findings could be used to help farmers with the
control of the insects which do harm to their plants.