1 . The San Francisco-based company, called Living Carbon, has created poplar (杨树) trees that are genetically engineered (改变基因结构) to grow larger and suck up more carbon dioxide from the atmosphere than standard trees do. In February, workers planted rows of these poplars in southern Georgia. The company intends to plant 4 to 5 millions trees by the middle of next year, which they say will help with the worsening climate crisis.
When plants photosynthesize (进行光合作用), they convert carbon into sugar and nutrients that are eventually consumed by all living organisms. But they also produce a harmful byproduct, which must be broken down during the energy-intensive process of photorespiration (光呼吸), said Yumin Tao, the company’s vice president of biotechnology.
“This is not only wastes energy but also loses much fixed carbon in the form of CO2, which gets released into the air again,” Tao added. “It’s a wasteful process many plants do.” Living Carbon has reduced photorespiration in its poplars, instead channeling the energy into growth, he says.
The trees have three genes inserted to achieve this, including one from squash and one from green algae. But the company has yet to show its modified trees can capture more carbon in a real — world setting. Its only publicly available data comes from a study in a greenhouse that lasted for only a few months and has yet to be peer reviewed. “Their claims seen bold based on very limited real-world data,” says Andrew Newhouse, a conservation biologist at the SUNY College of Environmental Science and Forestry.
Still, the study reported the modified poplars grew as much as 53% larger in five months compared to the unmodified ones, capturing 27% more carbon dioxide. Now, the company hopes its other field trials in locations like Oregon and Pennsylvania will show similar successes. It’s currently focused on planting on private lands, where fewer roadblocks exist.
“We specially focus on land where trees otherwise wouldn’t be planted, like abandoned mine lands-areas where there isn’t an existing, rich ecosystem that’s allowing for a large amount of carbon removal right now,” says Maddie Hall, Living Carbon’s CEO.
1. Why does the company want to plant genetically modified poplars?| A．To help with the worsening climate crisis. |
| B．To better study them to gain more accurate data. |
| C．To replace ordinary poplars with genetically modified poplars. |
| D．To find suitable places for genetically modified poplars to grow. |
| A．Disapproving. | B．Ambiguous. | C．Skeptical. | D．Supportive. |
| A．They are very resistant to carbon. | B．They have a growth advantage. |
| C．They have two genes inserted. | D．They photosynthesize even faster. |
| A．A Company Is Trying to Engineer Trees Genetically |
| B．Poplar Trees Might Be Planted All Around the World |
| C．Genetically Modified Trees Are Taking Root to capture Carbon |
| D．Research Is Being Conducted to Use Trees to Remove CO2 |
2 . Yellow flower carpeted fields are a sure sign of summer. In Denmark alone, more than 200,000 hectares of rapeseed (油菜籽) are planted every year. But until now, the plant has only been used for oil and animal food, as it is both bitter and unsafe for human consumption.
To protect themselves, the rapeseed plants produce a group of substances (物质) called glucosinolates (硫苷), which give the plants a strong and bitter taste that scares off insects and disease. As a result rapeseed is unhealthy to eat and the rapeseed cake, which is the remains of the seeds after the oil has been squeezed out, has only been used as feed for pigs and chickens, despite its 30 — 40 percent protein content.
Now, researchers from the University of Copenhagen have discovered the three proteins that help to store the bitter substances in seeds of thale cress (阿拉伯芥), a plant closely related to the rapeseed. The new knowledge makes it possible to prevent the accumulation (积聚) of these substances in the seed by removing the proteins through “transport engineering” technology. In doing so, the defensive substances remain in all other parts of the plant, allowing it to continue to defend itself.
So far, the researchers have shown that their method works in thale cress. “The next task is to apply our method to the closely related rapeseed plant, which we are now working on,” says Professor Halkier, leader of the research.
“Half of plant proteins in the EU come from rapeseed. The climate crisis demands that we reduce meat consumption and eat more plants, which is where rapeseed has great potential as a new source of plant protein. Our latest research results bring us a step closer to making full use of rapeseed,” says Professor Halkier.
1. What is the function of paragraph 2?| A．To state the reason. | B．To offer the solution. |
| C．To give an example. | D．To introduce the topic. |
| A．By selecting better seeds. | B．By removing the three proteins. |
| C．By increasing sweet tastes. | D．By storing defensive substances. |
| A．Researchers’ efforts to better the taste. |
| B．Researchers’ progress in their experiment. |
| C．Rapeseed’s role in relieving climate crisis. |
| D．Rapeseed’s potential as a new protein source. |
| A．Harmful proteins discovered in rapeseed |
| B．Rapeseed widely used as oil and animal food |
| C．Researchers closer to making rapeseed safe food |
| D．New plant protein in rapeseed finally uncovered |
