One day, “supercharged plants” may help feed people around the world. Supercharged plants are ones that grow faster than normal plant life. Scientists can speed up the growth by modifying, or changing, the structure of plants' genes. The modifications make them react quickly to changes in light. This all has to do with photosynthesis(光合作用), the process in which plants turn sunlight, carbon dioxide and water into food.

Plants grow fastest in the sun. That is when they make the most food for themselves. But their rate of growth can slow when things like clouds or trees block sunlight. But when the sun returns, it can take many minutes for growth to speed up again.

This can be a problem because it means some of our most important crop plants are not as productive as they could be. Researchers say demand for food is expected to increase up to 70 percent by the middle of the century. They also note rising temperatures on Earth's surface. That is why they are looking for ways to improve photosynthesis and make plants more productive.

Steve Long is a plant biologist at the University of Illinois. He wanted to find a way to help plants get back up to speed quickly after a period of darkness. So he and his team added genes that shortened the recovery time. It also increased the speed at which the plants grew. His modified plants grew up to 20 percent more than untreated ones.

In Long's study, his group used a form of genetic engineering called transgenics (转基因). It means taking genes from one plant, then putting them into another. Now they are experimenting soybeans, rice, cowpeas and cassavas.

【小题1】What is the advantage of supercharged plants?

A．They can grow more quickly.

B．They can grow in severe conditions.

C．They can offer high-quality grains.

D．They can replace normal plants.

【小题2】What can make plant growth slow down?

A．Too hot weather.	B．Old farming methods.
C．Lack of sunlight.	D．Too much sunlight.

【小题3】What was Steve Long's goal in his study?

A．To find out what makes plants grow slowly.

B．To create a new plant that can grow with weak sunlight.

C．To find another way to help plants benefit each other.

D．To make plants recover quickly when the sun returns.

【小题4】How can researchers shorten the recovery time of plants?

A．By changing their nature.	B．By adding new genes to them.
C．By developing new plants.	D．By supplying more sunlight.