The ginkgo (银杏) tree is thought to be one of the oldest living trees,
Ginkgoes are large trees,
With fan-shaped leaves, ginkgoes are green both on the top and bottom. But during autumn, they turn bright yellow and then fall, which make up
Because ginkgoes
2 . Maybe you’ve wondered what you would hear if plants could speak. A stream of gossip from the roses? Wise whispering from the branches of an old tree? A faint, high-pitched cry of terror when your older brother takes out the lawn mower(割草机)?
Ariel Novoplansky, an ecologist in Israel, is studying how plants communicate with each other. To listen in, he set up a kind of telephone game among plants in his lab. Experiment used pea plants standing in rows of containers. The center plant in each row was the target: Scientists would stress out that plant and see whether the plants on either side of it picked up any alarm signals.
The pea plants had been grown with two main roots. On one side of the stressed plant, each plant had one root in its own pot and the other reaching into a neighbor’s pot. The central plant connected to its closest neighbor, which connected to another neighbor, and so on down the line. On the other side of the stressed plant, all the plants kept their roots in their own pots unconnected to their neighbors. Then the scientists dried up the soil of the central target plant, creating a drought.
Within 15 minutes, the dried-out plant reacted the same way it would in nature: it had closed up the tiny pores(气孔) on its leaves to save water. What’s amazing is that the central plant’s closest neighbor with connected roots had also closed up its leaf pores. And after an hour, the message had traveled down the whole row of connected plants. On the other side of the pea chain, where the plants’ roots weren’t connected, all their pores stayed open. This means the warning signal traveled from the stressed plant’s roots through the soil.
Dried-out roots aren’t the only talkative plant parts scientists have discovered. When sugar maple trees are damaged, they send signals through the air telling their neighbors to produce bad-tasting chemicals. When caterpillars chew on corn leaves, nearby corn plants also make more self-defense molecules(分子). The plants around us may not be speaking with any volume, but they are saying plenty.
1. What is the purpose of paragraph 1?A.To make a prediction. | B.To raise a discussion. |
C.To develop a theory. | D.To introduce a research. |
A.By stressing out the target plant. |
B.By sending alarming signals to plants. |
C.By growing pea plants with different roots. |
D.By drying out the soil of the plants in rows. |
A.They are able to communicate with the gardeners. |
B.They send warning signals to others through the air. |
C.They close up their leaf pores as a stress reaction. |
D.They are the most talkative plants found by scientists. |
A.A news report. | B.A science journal. |
C.A gardening guide. | D.A business magazine. |
The Amazon rainforest is home to a great
4 . “A beautiful field of flowers can be a rather noisy place. It’s just that we can’t hear the sounds.” Scientists at Tel Aviv University have conducted a six-year experiment, proving that plants make noise in certain stressful situations.
Plants produce a high frequency (频率) clicking sound, and when short of water, or damaged, the clicks become far more regular. They also made different sounds, depending on whether they were thirsty or injured. “Each plant and each type of stress is related to a specific sound,” said Professor Lilach Hadany, who led the research study.
Focusing particularly on tomatoes, wheat and corn, the plants were placed in a soundproof(隔音的)room and recorded by microphones. Some plants were starved of water, others cut, and a control group was left undamaged. The researchers used an algorithm (算法) to separate the noises, suecessfully telling the difference between the sounds depending on whether they were dry or cut. The algorithm did this in a greenhouse setting which included far more surrounding sounds, but it was still able to recognize the particular cries for help of the plants.
On average, the human ear can hear sounds up to around 20kHz, while the sounds produced by plants are in the 40-80kHz region, far beyond our hearing. “The sounds made by plants can’t be heard by humans but can probably be heard by various animals, such as bats, mice and insects,” Hadany tells us. Though this has yet to be proven, it’s possible that these creatures use this information to choose which plants to eat.
A study led by Reda Hassanien of China Agriculural University in Beijing years ago, also proved that plants reacted to sound waves, with some plants greatly increasing their yield. While evidence shows that plants can react to sounds, there’s no evidence today that they can actually hear them.
1. What can we know from the six-year experiment?A.Plants of different types make the sound of the same frequeney. |
B.Plants produce more regular sound in certain stressful situations. |
C.Plants make sounds with a much lower frequency when stressed. |
D.Plants make the sound of the same frequeney whatever the situation. |
A.To record the sounds. | B.To control the sounds. |
C.To produce the sounds. | D.To identify the sounds. |
A.Plants can hear each other’s cry for help. |
B.Animals can hear the sounds made by plants. |
C.Plants can make sounds and respond to sound waves. |
D.Animals decide what to eat based on the sounds plants make. |
A.Sounds That We Can’t Hear |
B.Beautiful Songs from Plants |
C.Plants React to Different Types of Stress |
D.Plants Talk, Especially When Stressed |
With high yield and superior quality, Chinese hybrid rice varieties have been introduced around the world,
In the past 40 years, Chinese scientists
Yuan Longping,
It
6 . For the first time, scientists have provided clear evidence that tropical tree lifespans(寿命) decrease above a critical temperature threshold. Findings published in the journal Proceedings of the National Academy of Sciences show that across the tropics, tree lifespans decrease for temperatures above 25℃.
As temperatures are rising rapidly across large parts of the tropics, the tree death rate is likely to rise in most parts of the tropics, including the Amazon, Pantanal and Atlantic forests, with possible effects on animal habitats, air quality and carbon stocks. Although tropical rainforests account for only 7% of all land, they are home to about 50% of all animals and plant species, and approximately 50% of forest carbon stocks on earth. Thus, small changes in the functioning of tropical forests can significantly change the atmospheric levels of CO2-the most important greenhouse gas caused by humans.
Professor Manuel Gloor and Dr Roel Brienen, the Leeds School of Geography, are co-authors of the new study. Professor Gloor said: “Many regions in the tropics are heating up particularly rapidly and a large number of areas will become warmer, on average, than approximately 25℃. Our findings suggest that for trees in these regions, their lifespans are likely to be negatively affected.”
Dr Brienen added, “This indicates that tropical forests may be more vulnerable(易受伤害的) to increasing heat than previously thought. As a result of global warming, we therefore expect the shortening of tree lifespans in the tropics. These results are a warning sign that, along with deforestation, global warming puts extra stress on the Earth’s tropical forests.”
The research team, led by Dr Giuliano Locosselli, from the Institute of Biosciences, University of Sao Paulo, Brazil, spent four years examining tree-rising data from more than 100,000 trees worldwide belonging to 400 different tree species from 3,000 sites across the globe. Dr Locosselli said, “In the tropics, trees grow, on average, twice as fast as those in cooler regions of the world. But they also have a shorter average lifespan of 186 years, compared to 322 years for trees in other climates. Our analysis suggests that the lifespans in the tropics will likely decrease further still.”
“If tropical trees die earlier, this will affect how much carbon these forests can hold, raising concerns about the future potential of forests to balance CO2 emissions(排放) from fossil fuels burning. It could also cause changes in biodiversity and a decrease in the number of species on the planet.”
Currently, average temperatures in tropical rainforests vary between 21℃ and 30℃. According to the latest forecasts, tropical temperatures on land will continue to rise, reaching on average a combined 2.5 ℃ above pre-industrial levels over the next 10 to 20 years. The study also shows that temperature effects on tree longevity(长寿) will be further worsened by dry conditions.
1. What does the underlined word “threshold” in the first paragraph probably mean?A.Assumption. | B.Boundary. |
C.Controller. | D.Distinction. |
A.They occupy a large part of the land on earth. |
B.They stock the carbon of almost the whole forest. |
C.Their ability to absorb CO2 is weaker than expected. |
D.They are home to about half the creatures on earth. |
A.They live for a much shorter time on average. |
B.They have fewer species and living sites globally. |
C.They are not as strongly affected by temperature. |
D.They grow much slower than those in cooler regions. |
A.Tropical trees dying much faster. |
B.Tropical trees releasing more heat. |
C.Tropical trees catching fire more often. |
D.Tropical trees standing hotter temperatures. |
7 . Plants and exposure to greenery have been found to have multiple mental health benefits, such as lowering stress, decreasing feelings of depression, increasing sociability, restoring focus, improving cognitive performance, improving mood, and increasing self-esteem.
Gardening and care for plants can help to turn people away from negative thoughts or emotions. So with all that, what do these experts recommend as the best plant?
Snake plant. It’s very easy to care for, thrives in spaces with low sunlight, has visual appeal, and cleans the air, and they are drought resistant if you forget to water them.
Spider plants. Spider plants, with plenty of light-green leaves, are another low-maintenance selection.When a spider plant thrives, it will grow new offshoots that can be clipped and potted as a new plant.
Aloe Vera. Drought-resistant and easy to grow. Aloe Vera is low-maintenance, you can just water it monthly, and it helps clean the airspace and is helpful for burns, cuts, and scrapes to help injuries heal faster or soothe pain.
Lavender is well-known for its relaxing scent, and it has a calming effect, aids in reducing stress, promotes sleep.This means it’s great both in the garden, or clipped and dried in a bowl inside your space .
Basil is a summertime herb that loves the sun. Not only is it delicious in meals, but eating basil has health benefits, too. It has properties which help to relieve stress and anxiety.
Lemon balm. This fragrant green herb is part of the mint family and is simple to cultivate. Known for its calming properties, it has a light lemony scent that can be wonderfully intensified by rubbing the leaves between your fingers. It has been used to improve sleep, reduce stress and anxiety, improve appetite, and help with indigestion.
1. What can we know from the passage?A.Spider plants will still survive if you forget to water them. |
B.Lavender is recognized for its mint scent and calming effects. |
C.Snake plants grow well in spaces without enough sunlight. |
D.Basil is not edible but has some valuable properties. |
A.They need little water. | B.They appeal to the eye. |
C.They help us calm down. | D.They enhance health. |
A.Two | B.Three | C.Four | D.Five |
8 . High-resolution (高分辨率) satellite imagery has been used to map every single tree in Africa, showing a technique that could help improve the monitoring of deforestation (森林砍伐) across the world. Florian Reiner at the University of Copenhagen, Denmark, and his colleagues used images from sate lies to map canopy (树冠) across the entire African continent.
Modern sate lies usually catch tree canopies at a resolution of 30 meters — fine for measuring the size of forests, but less good at mapping individual trees. The satellite data Reiner and his colleagues used had a resolution of 3 meters, enabling the study to map all trees, including those not part of a forest.
The results suggest that 30 percent of all trees in Africa aren’t in a forest and instead are across farmland, savannah and urban areas. “Many countries in Africa lack thick forests, but have a lot of trees.” says Reiner. “These trees are extremely important to the local ecosystems, the people and the economy. By tracking every single tree, researchers can start to monitor how these trees are coping with climate change or whether they are sensitive to deforestation.” It could also improve the monitoring of reforestation efforts, which are growing in popularity as a way of removing carbon dioxide from the atmosphere.
“At a local level, being able to consistently monitor when and where trees are disappearing or reappearing can lead to more actionable insights,” says John Francis at the Alan Turing Institute in London.
“The study is a proof of concept rather than a map ready for immediate commercial use,” says Reiner. “It’s research work. It’s showing what could be done,” he says. But he is already working with colleagues to scale up the tracking approach to cover the entire global canopy: “We’re hoping that this will be seen as a way forward in monitoring tree resources.”
1. Why is high-resolution satellite imagery used to map every single tree?A.To know the exact height of the tree. |
B.To have a clear picture of the canopy. |
C.To help monitor the deforestation. |
D.To improve the satellite technology. |
A.Doubtful. | B.Disapproving. | C.Indifferent. | D.Favorable. |
A.Protect the trees only in Africa. |
B.Put the map into commercial use. |
C.Track the entire global canopy. |
D.Improve the imagery technology. |
A.Ways to Measure the Size of Forests in Africa |
B.Coping with Climate Change by Tracking Every Single Tree |
C.A Map from the Satellite Ready for Immediate Commercial Use |
D.High-resolution Satellite Imagery Used in Monitoring Deforestation |
9 . The world loves a cup of tea. It only takes a few grams to make a cup of tea and millions of tons of tea are consumed every year. Tea can be good for you because it contains some things that help lower cholesterol and reduce the risk of cardiovascular disease. Tea also contains caffeine(咖啡因), which improves not only mental alertness but can also increase anxiety and cause other problems.
What would be agreeable is a tea plant that provides all the taste and goodness but with little or none of caffeine. Chen Liang and Jin Jiqiang in the Tea Research Institute, Chinese Academy of Agricultural Sciences think they have found just such a plant, growing wild in a remote area in southern China’s Fujian Province. Known locally as hongyacha, the discovered plant grows only between 700 meters and 1,000 meters above sea level around a handful of Chinese villages. As they report in the Journal of Agricultural and Food Chemistry, not only is the tea plant naturally caffeine-free but it also contains a number of unique medicinal compounds that, the locals believe, offer considerable health benefits.
The researchers are now exploring methods to protect hongyacha in its natural habitat while further studies are carried out. It can take time—and sometimes it does not work—for new plant varieties to be bred for commercial use. A pair of naturally caffeine-free coffee plants were discovered in 2003, but little progress has been reported. Tea lovers will be watching hongyacha with interest. And others will wonder what else is out there.
1. What’s the disadvantage of drinking tea according to paragraph 1?A.It can make people hard to sleep. | B.It can make people feel anxious. |
C.It can get people addicted. | D.It can take people much time. |
A.It is nothing but just medicine. | B.It can only survive in greenhouses. |
C.It is a good pick for caffeine lovers. | D.It has a good taste and little caffeine. |
A.Its future location. | B.Its natural habitats. |
C.Its future market. | D.Its production process. |
A.A health magazine. | B.An advertising brochure. |
C.A travel guidebook. | D.A newspaper. |
10 . Wildfire season has begun in many places around the world. The dangerous smoke wildfires produce can spread far and wide. It blocks sunlight, poisons the air and damages the health of people and other living things.
Some of those living things could be the plants in gardens, says gardening expert Jessica Damiano, who writes gardening stories for the Associated Press. Damiano lives in New York City and recently experienced several days of very smoky air. Wildfires in eastern Canada were the source.
Damiano, like other people, limited the time she spent outdoors when the air quality was poor. She also wore a face covering when she had to go outside.
But the plants in her garden had no such escape. They had to breathe the poisoned air through the extremely small holes in their leaves.
Pollutants in smoke landing on plants can block sunlight, which is essential for photosynthesis (光合作用). Reduced photosynthesis results in reduced energy. That means slower growth. Additionally, smoke can also affect a plant’s ability to take in nutrients(营养物质).
Brooke Edmunds, a plant scientist and community horticulturalist with Oregon State University Extension, said plants that are affected by smoke for a short amount of time will usually recover quickly. “It depends on how close they are,” she said. “There could also be a localized effect, where one garden is covered in ash(灰烬), and a half-mile away, there’s nothing because that’s the way the wind was moving things around.”
The best thing home gardeners can do is keep an eye on plants. Edmunds suggests giving plants some extra love and care. “Wash the plants gently to remove pollutants left by smoke. Then give them a long, slow drink of water. Most will pull through,” Edmunds said. However, people should not use leaf blower machines to remove ashes from plants because they will risk breathing in what is blowing around.
1. What happened to Jessica Damiano?A.She had her house burned in a fire. |
B.She couldn’t afford face coverings. |
C.She suffered from health problems. |
D.She had to deal with poor air quality. |
A.The bad effects of smoke on plants. |
B.The benefits of growing plants. |
C.The role of plants in the environment. |
D.The importance of water to plants. |
A.Wind has little effect on plants. |
B.Plants can sometimes make a quick recovery. |
C.Ashes can spread more than half a mile. |
D.Plants close to smoke usually grow well. |
A.By pulling them out of the ground. |
B.By using leaf blower machines. |
C.By washing them with great care. |
D.By giving them a fast drink of water. |