1 . Under a midday summer sun in California’s Sacramento Valley, rice farmer Peter Rystrom walks across a dusty and bare plot of land, dry soil crunching (碎裂) beneath each step. In a typical year, he’d be walking across green rice fields in inches of water. But today the soil is dry and baking in the 35℃ heat. It hasn’t rained for 4 weeks in a row.
“Climate change is expected to worsen the state’s extreme swings in rainfall,” researchers reported in Nature Climate Change in 2018. Low water levels in rivers have forced farmers like Rystrom, whose family has been growing rice on this land for four generations, to reduce their water use.
“If we lose our rice crops, we have to deal with severe food crisis. Climate change is already threatening rice-growing regions around the world. This is not a future problem. This is happening now,” says plant geneticist Pamela Ronald of the University of California, Davis, who identifies genes in rice that help the plant stand up to dryness, disease, flood, etc.
To save and even boost production, rice growers, engineers and researchers have turned to water-saving irrigation (灌溉) routines. Building canal systems and reservoirs (水库) can help farmers dampen their fields. But for some, the solution to rice’s climate-related problems lies in enhancing the plant itself. They hold that establishing rice gene banks that store hundreds of thousands of rice varieties ready to be bred into new, dryness-tolerant varieties is more practical and effective. Solutions may be hidden in the DNA of those older breeds.
Three decades have passed since its initial development, and some researchers are looking beyond the genetic variability preserved in rice gene banks, searching instead for useful genes from other species, including plants and bacteria. But picking genes from one species and putting them into another, or genetic recombination, remains debatable. The most famous example of genetically changed rice is Golden Rice (GR). “Looking ahead, it will be crucial for countries to embrace GR rice. But it will take time,” says Ismail, principal scientist at IRRI,
1. What problem does Rystrom have to deal with?| A．Thirst. | B．Drought. | C．Hot sun. | D．Dusty weather. |
| A．Downtrend of rice-growing areas is severe now. |
| B．Climate change is a threatening factor in the future. |
| C．Humans will face starvation if crop failure happens. |
| D．Food crisis is a common occurrence around the world. |
| A．To store as many seeds as possible. | B．To cultivate climate-adapted varieties. |
| C．To improve the efficiency of breeding. | D．To show the technology of gene mapping. |
| A．Favourable. | B．Impractical. | C．Disapproving. | D．Insecure. |
Camellias (山茶花) are available in a great range
In the 1960s, Chinese scientists announced their discovery of the golden camellias. It was an
Unfortunately, in the past, golden camellias were cut down in large numbers because
Year after year, the Huang brothers spent much time working
1. Why is the baobab’s trunk really fat?
| A．It is shaped by people. |
| B．It stores a large quantity of water. |
| C．It must be strong enough to support the tree. |
| A．About 12 metres. | B．About 15 metres. | C．About 30 metres. |
| A．Shops. | B．Wildlife habitats. | C．Bus shelters. |
4 . According to a new research, flowers are listening. Researchers found that plants can actually hear the sound of passing bees and produce sweeter nectar (花蜜) to attract them.The team discovered that within minutes of sensing the sound waves of bee wings, the concentration of the sugar in the plant’s nectar was increased by 20 percent.
Also, flowers can remove the wind noise coming from the background. These capabilities can give plant advantages for their spreading pollen (花粉). The researchers showed that plants can rapidly respond to pollinator (传粉者) sounds.
Before the experiments, researchers made the assumption that plants can pick up the sound waves and that this might be part of the reason why many plants’ flowers are bowl-shaped, to better trap the sounds. However, after performing various experiments on 650evening primrose flowers, the nectar production was measured both in silence and at three different frequency levels. Also, a recording of the noise made by bees was played. In just three minutes, the nectar changes have been noticed and it has been release d that silence and the high and mid-frequency sounds had no effect. The team has also performed an experiment with plants that had some flower petals removed and no change in nectar production was noted. Hence, it is proved that the flowers petals have the job of the ears.
The more sweet nectar comes out, the more will be the chances for pollen to be spread and also makes it more likely that the insects will return to flowers of the same species in the future. However, more work needs to be carried out on how the sounds are turned into a trigger for sweeter nectar production.
1. Why do plants produce sweeter nectar?.| A．To attract bees. | B．To be more beautiful. |
| C．To avoid enemies. | D．To drive insects away. |
| A．Why researchers did the experiments. | B．How researchers made the discovery. |
| C．What use can be made of the discovery. | D．What the importance of the discovery is. |
| A．High sound increases sugar in the nectar. |
| B．Many plants’ flowers are bowl-shaped to catch light. |
| C．Flowers petals have no effect on nectar production. |
| D．More research is needed to fully understand the process. |
| A．A diary. | B．A novel. | C．A newspaper. | D．A notebook. |
5 . It turns out that plants are getting help from their friends underground—quite a bit more than scientists had realized. A global team of researchers has calculated that around 36% of the carbon released into the atmosphere each year from the burning of fossil fuels is captured and delivered to a complicated system of fungi that lives beneath our feet.
Plants take carbon dioxide from the air and use it to make sugars and fats. These are sent down to their roots, where they are taken up by so-called mycorrhizal (菌根) fungi. In exchange, the fungi provide the plants with water and essential nutrients from the soil. The more carbon these fungi are able to draw in， the more carbon dioxide gets captured by plants.
Mycorrhizal fungi helped plants get established on land several hundred millions of years ago, and today’s plants would have a hard time functioning without their partners under the ground. Yet “mycorrhizal fungi have been largely overlooked,” said To by Kiers, executive director of the Society for the Protection of Underground Networks. “They represent an incredibly important part of the carbon cycle, and we are only just beginning to understand how they work,” she said. “The urgency to understand that and link it to biodiversity belowground is the most important.”
The researchers also said that plants associated with mycorrhizal fungi can take in eight times more carbon than plants that are not. Stephanie Kivlin, an ecologist at University of Tennessee, said the study is a crucial step toward improving our understanding of the plant-fungi duo’s role in reducing carbon dioxide in the atmosphere. “These mutualisms (互利共栖) can act as a critical carbon sink in many ecosystems on the land,” she said.
Not only do the fungi take in carbon from plants, they also help keep that carbon safely belowground by creating a sticky compound that holds the soil together. Although mycorrhizal fungi have short life spans-only a few years—their usefulness doesn’t end after death. “This is my favorite part,” Kiers said. “After they die, they make a dead underground network that acts as a scaffolding to hold the soil together, locking the carbon in place. ”
1. What do the researchers find?| A．Fungi absorb carbon from plants. | B．Carbon is essential to plants. |
| C．Carbon is released into the air. | D．Plants exchange food with fungi. |
| A．Carbon sink reduces carbon dioxide. | B．Carbon cycle is linked to biodiversity. |
| C．Plants nowadays take in carbon as usual. | D．Plant-fungi system functions efficiently. |
| A．They become sticky scaffolding. | B．They help prevent carbon release. |
| C．They provide vital nutrients. | D．They change into fossil fuels. |
| A．A complicated problem. | B．An overlooked plant. |
| C．An underground green guard. | D．A useful ecosystem. |
6 . We are learning more and more every day about just how smart some animals are: monkeys, some species of birds, dogs, cats. But how about other animals? Snails? Mosquitos? They sure seem less smart. Still smarter than plants, though. Because it would be difficult to argue that plants are intelligent. Or would it?
In a new study, it was shown that plants send out sounds when they are sad. And these sounds are very different depending on whether they have recently been cut or whether they don’t have enough water. The sounds can’t be heard by human ears, as they are between 20 and 100 kilohertz, which is above the bottom of human hearing (which usually has the upper limit of 15-17 kilohertz).
These are fantastic results: plants don’t suffer in silence; they are screaming with pain. That is exactly what the popular science press has been doing.
There is no evidence that they are heard by anyone although theoretically (理论上) some animals — bats, moths, mice — could actually hear it as their ears are sensitive to the plant sounds. And it could very well be a byproduct (副产品) of the physical condition of these plants: less water in the system leads to more air bubbles (气泡) in plants, which leads to the sound of the popping of these bubbles.
Is this a disappointing explanation? I don’t think so. The aim is to understand why plants do what they do. And the results about the sounds contribute to this body of knowledge. They could even lead to better ways of controlling the needs of plants in gardening by sound observation.
All of this is true even if the plants don’t strictly “cry” or “scream”.
1. Why are we unable to hear the sounds of plants?| A．Because they are imagined by humans. |
| B．Because they go beyond human hearing. |
| C．Because plants don’t actually give off sounds. |
| D．Because plants are not as intelligent as animals. |
| A．Plants keep silent even when they suffer. |
| B．Water in the plants sends off different sounds. |
| C．The plant sounds might show their feelings or needs. |
| D．The study aims to control the needs and feelings of plants. |
| A．Because plants don’t actually “cry” or “scream”. |
| B．Because the results prove their knowledge of plants. |
| C．Because the results show that-plants understand what they do. |
| D．Because plants’ demands could be met by observing their sounds. |
| A．Plants suffer in silence | B．Plants “cry” in pain |
| C．Plants “scream” with joy | D．Plants need attention |
7 . Plants do not suffer in silence when thirsty or stressed, according to a new study published today in Cell.
Plants that need water or have recently had their branches cut produce up to roughly 35 sounds per hour, the authors found. But well-watered and uncut plants are much quieter, making only about one sound per hour.
The reason why you have probably never heard a thirsty plant make noises is that the sounds are so high-pitched that very few humans could hear them. Some animals, however, probably can. Bats, mice and moths could possibly live in a world filled with the sounds of plants, and previous work by the same team has found that plants respond to sounds made by animals, too.
To overhear plants, Lilach Hadany at Tel-Aviv University in Israel and her colleagues placed tobacco and tomato plants in small boxes provided with microphones. The microphones picked up any noises made by the plants, even if the researchers couldn’t hear them. The noises were particularly obvious for plants that were stressed by a lack of water or recent cutting.
Plants do not have vocal cords (声带) or lungs. Hadany says the current theory for how plants make noises centers on their xylem (木质部) that transport water and nutrients from their roots to their branches and leaves. Water in the xylem is held together by surface tension, just like water moving through a drinking straw. If an air bubble (气泡) forms or breaks in the xylem, it might make a little popping noise; bubble formation is more likely during dry seasons. But the exact system requires further study, Hadany says.
The team produced a machine-learning model to check whether a plant had been cut or was water-stressed from the sounds it made, with about 70% accuracy. This result suggests a possible role for the audio monitoring of plants in farming and gardening.
To test the practicality of this approach, the team tried recording plants in a greenhouse. Pilot studies by the authors suggest that tomato and tobacco plants are not exception. Wheat, corn and wine grapes also make noises when they are thirsty.
1. What is the new research mainly about?| A．Plants can react to animals. | B．Plants can produce sounds. |
| C．Well-watered plants keep silent. | D．Branchless plants need watering. |
| A．They can create more bubbles. | B．They can feel less stressed. |
| C．They require less nutrient supply. | D．The y need lungs to breathe more. |
| A．Fruit growing. | B．Crop selection. |
| C．Water source protection. | D．Noise pollution test. |
| A．How Plants Are Thirsty | B．When Nature Expresses Itself |
| C．How Plants Cry for Their Needs | D．When Creatures Hear Each Other |
8 . A Fish and Wildlife Service proposal would protect the whitebark pine as an endangered species. Whitebark pines can live for up to 1,000 years and grow at elevations (海拔) as high as 12,000 feet. Environmentalists had requested the government in 1991 and again in 2008 to protect the trees. A nonnative fungus (真菌) has been killing whitebark pines for a century. More recently, the trees have proved vulnerable (易受伤的) to tiny insects that have killed large areas of forest.
The whitebark pines have almost disappeared in some areas, including the eastern edge of Yellowstone National Park, where they are a source of food for threatened grizzly bears (灰熊). This makes the government’s declaration of the Yellowstone area’s grizzly bears as a restored species a lie.
After being blamed for not taking steps to protect the trees, wildlife officials in 2011 admitted that whitebark pines needed protection, but they didn’t act rapidly, saying other species faced more immediate threats.
A lawyer for the Natural Resources Defense Council, which made the formal request for protection in 2008, expressed his disappointment that it took so long but said the proposal was still worth celebrating.
The government’s proposal described the threats to the trees as immediate and said the whitebark pines were one of many plants expected to be harmed as climate change moves faster than they can adapt. “Whitebark pines survive at high elevations already, so there is little remaining habitat in many areas for the species to move to higher elevations in response to warmer temperatures,” Fish and Wildlife Service officials wrote.
Government officials are working with researchers and private groups on plans to gather seed from trees, grow them in greenhouses and then plant them back on the landscape, according to Fish and Wildlife Service biologist Amy Nicholas. A proposal of that nationwide restoration is expected by the end of this year. “We do have options to restore this species,” Nicholas said.
1. What do we know about whitebark pines?| A．They are long-lived, high-elevation trees. |
| B．They have a strong resistance to nonnative fungi. |
| C．The government used to care about protecting them. |
| D．They and small insects depend on each other for survival. |
| A．Grizzly bears are no longer threatened. |
| B．The whitebark pines have almost disappeared. |
| C．The population of grizzly bears has increased greatly. |
| D．The government is actually doing nothing to protect bears. |
| A．Better late than never. | B．All roads lead to Rome. |
| C．Never do things by halves. | D．The first step is the hardest. |
| A．Irresponsible. | B．Doubtful. | C．Optimistic. | D．Uncertain. |
9 . Worldwide, there are more than a thousand mistletoe (槲寄生) species. They grow on every continent except Antarctica. They are parasites(寄生物) and live on the branches of their plant “hosts”, absorbing water and nutrients to survive. They accomplish this thievery via a specialized structure that infects their hosts. In fact, they infect plants of all kinds, including themselves—a number of species have been documented parasitizing other mistletoe species.
Yet despite their parasitism, mistletoe species may well be the Robin Hoods of plants.(Robin Hood is a character in old English stories who lives in a forest with a group of friends and steals money from rich people in order to give it to poor people.) They provide food, shelter and hunting grounds for other animals. Fallen mistletoe leaves release nutrients into the forest floor that would otherwise remain locked within trees, and this generosity benefits the food chain. “Yes, ecologically, they are cheats,” says David Watson, a community ecologist at Charles Sturt University at Albury-Wodonga, Australia. But they share their wealth. “They steal these nutrients, and then they drop them,” Watson says.
Mistletoe species depend critically on animals to get around. Most mistletoe fruits are berries containing a single seed that’s surrounded by a sticky layer. Roughly 90 bird species are known to consume mistletoe species’ seeds, so the birds can pass them to other trees on their bodies, or when they are eaten, seeds are passed through their waste. (There are exceptions: Some mistletoe species make explosive fruits that send their seeds toward nearby trees, reaching distances of 10 meters or more.)
Scientists have known that mistletoe species all have ancestors that were parasites not on branches, but on roots. “They evolved over and over and over, and this understory, root-parasitic, shrubby thing switched to being an aerial(meaning they infect above-ground plant parts, rather than roots), parasitic shrubby thing,” Watson says. Moving up the tree helped to solve a problem that all plants are faced with: competing for sunlight. Despite their parasitic nature, most mistletoe species still use energy from light to make their food.
1. What can we learn about mistletoe species according to paragraph 1?| A．They are highly independent. | B．They are harmful to their hosts. |
| C．They can be found on every continent. | D．They prefer to live on the roots of plants. |
| A．They help poorly grown trees absorb more nutrients. |
| B．They have remarkable abilities to survive in the forest. |
| C．They live in the forest with other plant species in groups. |
| D．They steal and give food to many other living things. |
| A．With the help of birds. | B．By making explosive fruits. |
| C．With the help of nearby trees. | D．By taking advantage of hosts’ seeds. |
| A．They eventually evolved into shrubby plants. |
| B．Their habitats changed from roots to branches. |
| C．They tried to give up using energy from sunlight. |
| D．Their parasitic nature was formed in a gradual way. |
10 . Color is important for all gardens, no matter what size. Kalanchoes (长寿花) offer kinds of colors, from energetic oranges, yellows and reds, to calming pinks and creams. They’re easy to care for.
Be striking. Colorful plants are mood-boosting as well as a great way to lift a small outside space. Kalanchoe is a flowering succulent (多肉) that comes in a range of lively shades and looks delightful when grouped in large pots or window boxes.
Think big. When space is limited, people tend to choose lots of small containers, but a few large pots can fool the eye into believing there’s more room than there is. Try planting taller plants, such as roses or hydrangeas, alongside smaller species, like kalanchoes.
Indoors out. Making your outside space clean needn’t be costly. Houseplants, like kalanchoes, will happily live outside in pots or window boxes from May to September when there is no risk of frost, so you can simply move them outside for a more colorful life.
Make it easy.
Just choose a sunny spot and away you go!
| A．Be style smart |
| B．Not all plants need a lot of attention |
| C．It is a great choice for the summer garden |
| D．Choose oranges and reds for an energy burst |
| E．You can find kalanchoes from most garden centers |
| F．Thus, you can create depth and a sense of richness |
| G．Given a little attention, they will reward you much flowering |
