1 . When micro-plastics end up in farm fields, the pollution can damage plant growth. But two young researchers now report that combining fungi (真菌) with certain farm wastes can partly overcome that problem.
May Shin, 20, and Jiwon Choi, 18, met in a research design class at the Fryeburg Academy, a high school in Maine. May had desired to explore how micro-plastics might affect the ecosystem. Jiwon was crazy about plants and fungi. The young scientists cooperated to test how long-lived plastics might affect farm crops.
Scientists have shown certain fungi can aid root growth and a plant’s nutrient uptake. Those organisms are named arbuscular mycorrhizal fungi (AMF). Certain farm wastes, like straw, can provide nutrients to plants and help stabilize their roots. Such wastes are also known as mushroom substrate (基质) and people often grow mushrooms in them.
May and Jiwon planted over 2,000 scallion (大葱) seeds in pots of soil. Half the seeds got soil polluted with micro-plastics. The rest grew in plastic-free soil. The plants then were further divided into four groups. The young scientists added AMF to the soil in one group. Another group had a top layer of mushroom substrate. A third group got both treatments. The last group got none. For three weeks, the pair tracked how many scallions sprouted (发芽) in each group and measured the plants’ height once each week.
About twice as many scallions sprouted in clean soil compared to that containing plastic bits. But among plants surviving in the polluted soil, a combination of AMF and mushroom substrate helped them out. Those getting both treatments grew 5.4 centimeters per week. That was faster than either of the treatments alone or those getting none.
Jiwon and May then looked at the plant roots with a microscope. Where AMF had been added, it grew into those roots. That increased the scallion roots’ surface area, May said, which should promote their uptake of nutrients. So “I see this project as coming up with a sustainable solution for plant growth in polluted soils,” said May.
1. Why did May and Jiwon work together?A.To see the effects of long-lived plastics on farm crops. |
B.To find the relationship between plants and fungi. |
C.To design a research on the growth of plants. |
D.To explore the way that the ecosystem works. |
A.To prove the existence of micro-plastics. | B.To compare fungi with farm wastes. |
C.To tell the advantages of farm wastes. | D.To provide some related information. |
A.Its purpose. | B.Its design. | C.Its findings. | D.Its reasons. |
A.By keeping the plants more resistant to pollution. | B.By allowing the plants’ deep area more freedom. |
C.By making nutrients more available to the plants. | D.By exposing the roots to a larger surface area. |
2 . When I was a kid, a sycamore (枫树) grew in front of my home. At the age of 10, I was just tall enough to reach its lowest branch and lift myself into its embrace. Sometimes two or three of my friends would join me in the sycamore, or in the maple down the street, or Mrs. DiMarco’s old peach tree, some of whose stout horizontal branches allowed us to sit shoulder to shoulder, eating sweet fruit.
In my small town there are some kinds of trees, their branches spreading wide, open for business. But I have not yet seen a climber. Perhaps computer games have replaced tree climbing, or maybe the activity went the way of monkey bars, which came to be viewed as too risky and have largely disappeared from playgrounds.
It is a sad loss. I have always believed that, since low-hanging branches provide no benefit to the tree, they must be meant for the child. Robert Frost understood this when he wrote:
When I see baches (桦树) bend to left and right,
Across the lines of straighter darker trees,
I like to think some boy’s been swinging them.
My only disagreement with Frost is his inference that tree climbing is a gender-specific task. Both boys and girls make a joyful climb.
The campus of the university where I teach has all sorts of trees. During a recent walk, I found myself bending under the branch of an immense spruce (云杉). I grabbed the thing, and a moment later was sitting on a branch. Then the memories came flooding back. The old sycamore, the friends, and finally, the reluctance to return to earth when the parental call to supper came.
I was so lost in my thoughts that I didn’t hear the student calling to me from below. He asked what I was doing. I didn’t waste time on explanations. “Come on up,” I said “The air’s fine.” But he only laughed and waved me off. He didn’t know what he was missing.
1. What does the underlined word “stout” in Paragraph 1 probably mean?A.Slim. | B.Bent. | C.Smooth. | D.Strong. |
A.Why kids don’t climb trees. |
B.Why monkey bars are dangerous. |
C.Why there is no business under trees. |
D.Why kids are addicted to computer games. |
A.Some branches of trees are useless. |
B.Trees are intended for kids to climb. |
C.Trees are a source of inspiration for poets. |
D.Climbing trees is a unique right of boys. |
A.The explanations to his question. |
B.The fresh air above the tree. |
C.The pleasure of climbing trees. |
D.The sense of safety on earth. |
3 . Now, a study proves that gardens are more than just a pretty place. The study, by researchers at Illinois State University, demonstrates that such constructed gardens can have a measurable and positive impact on water quality.
Floating gardens are essentially platforms built and wrapped in coconut husks (椰子壳), and filled in with native plantings. As plants grow, they extend their roots into the water. On the North Branch of the Chicago River, non-profit Urban Rivers and its partners are developing a mile-long floating eco-park called the Wild Mile. The re-development of this former industrial canal is Urban Rivers’ important project. As part of the park, floating gardens, attached to shore, are being fixed.
The primary aim of the floating gardens is beautification. But the Illinois State team, from the University’s Department of Geology, Geography, and the Environment, saw an ideal setup for a controlled experiment. “We joined it because it’s the perfect opportunity to see if there’s an influence on water quality,” explains lead author Abigail Heath.
The study is novel: previous studies have explored floating gardens’ influence on water quality over time, primarily in wastewater treatment ponds, but not over space, in moving water. The project also matches well with Urban Rivers’ broader goals. “The city is interested in bettering water quality,” says Phil Nicodemus, Urban Rivers’ Director of Research. “Happily, Illinois State took part in it later.”
Could this small human-made park improve water quality? An average of data collected over the course of the study shows middle but definitive improvement. For example, nitrogen (氮) dropped from 4.69 milligrams per liter in surface water to 4.43 milligrams per liter, a drop of about 1 percent.
“Despite how small this garden was, there was measurable improvement in water quality from upstream to downstream,” notes Heath. She and her colleagues see this as a model for how large floating gardens should be to help improve water in similar settings. “Even this tiny garden makes a difference,” she says.
1. What can be inferred from the second paragraph?A.The floating gardens are environmentally friendly. |
B.The floating gardens are fixed everywhere in the eco-park. |
C.The floating gardens can help fix the former parks. |
D.The Urban Rivers were once industrial canals. |
A.To reduce waste water. | B.To attract more visitors to the park. |
C.To make the surroundings brilliant. | D.To help researchers do the experiment. |
A.The floating garden. | B.The project. |
C.The treatment of ponds. | D.The quality of water. |
A.Floating Gardens: More than Pretty |
B.The Best Way to Better Water Quality |
C.A Practical Method of Improving Parks |
D.Floating Gardens Beautify the City |
4 . Fig trees are native to Europe around the Mediterranean Sea, Asia and Arica, but they can grow in much cooler climates.
Once big enough, fig trees can accept temperatures even a few degrees below freezing. Some kinds of fig trees do better in such environments than others.
Depending on the weather and pruning (修剪), a fig can grow into a bush or a tee. Bushes with several stems (茎) growing from the ground do best if covered for the winter.
One popular method for burying trees for their protection involves digging a narrow, shallow area.
Next, push a shovel (铲子) into the soil about a half-meter from the trunk (树干) on the side opposite the hole. Lift that side of the tree’s root ball out of the ground. Then, gently push the tree toward the hole.
Pack soil around the exposed side of the roots, and around the length of the tree. Load soil over the tree. Make it at least 30 centimeters deep. You will need more soil than you removed from digging.
A.And in this area the tree can be laid. |
B.All kinds of the trees could use protection. |
C.You can also cover, or wrap, the tree instead. |
D.And bend it around the bottom part of the tree. |
E.When it is lying fat, cover the tree with plastic. |
F.Trees with a single trunk can be buried or covered. |
G.Remove the cover on the tee on a cloudy day in early spring. |