1 . Scientists have shown how plants can protect themselves against genetic (基因的) damage caused by environmental stresses. The growing tips of plant roots and shoots have an in-built mechanism (机制) that spells cell death if DNA damage is detected, avoiding passing on faulty DNA.

Plants have small populations of stem cells (干细胞) at the tips of their roots and shoots, which enable them to continuously grow and produce new tissues throughout their lifetime. These stem cells serve as ancestors for plant tissues and organs. However, any genetic faults present in the stem cells will continue to exist and be passed on permanently throughout the plant’s life, which could last thousands of years.

Given the critical role of stem cells and their exposure to potentially dangerous environments at the growing tips of roots and shoots, safeguards are necessary to prevent stem cell faults from becoming fixed. Researchers Nick Fulcher and Robert Sablowski, funded by the Biotechnology and Biological Sciences Research Council, aimed to uncover these protective mechanisms. Through experiments involving X-rays and chemicals, they discovered that stem cells were more sensitive to DNA damage compared to other cells.

When DNA damage occurs, the cells have the capacity to detect it and cause programmed cells to die, preventing the propagation of the damaged genetic code to the rest of the plant tissues. This process has similarities to the safeguard mechanism found in animal cells, which has been broadly studied due to its relevance in preventing cancer.

The identification of a similar protective system in plants is of great interest in the field of plant development. It also helps scientists develop plants that can better handle environmental stress. So knowledge of how plants deal with these stresses is of fundamental significance to agricultural science’s response to climate change.

1. What is the function of the in-built mechanism in plants?

A．To produce more roots and shoots.	B．To increase the overall lifetime of the plant.
C．To enhance plant growth and nutrient intake.	D．To stop genetic faults in stem cells passing on.

2. What can we know about stem cells in plants according to the text?

A．They are relatively abundant in quantity.	B．They are resistant to environmental stresses.
C．They make quick response to DNA damage.	D．They have the ability to repair damaged DNA.

3. What does the underlined word “propagation” in paragraph 4 mean?

A．Spread.

B．Change.

C．Existence.

D．Self-repair.

4. What does the last paragraph focus on?

A．The way of dealing with climate change on the earth.

B．The significance of identifying the protective system in plants.

C．The method of ensuring plant survival under environmental stress.

D．The urgency of developing plants that can handle environmental stress.

2 . Growing plants is often seen as a very “green” thing to do, but like many products, they take a huge amount of energy to produce.    1    For example, they use geothermal(地热的) energy to heat greenhouses and solar power to supply electricity and lighting. While domestic growing doesn’t involve the same carbon footprint as commercial growing, it’s important to consider what we can all do to minimize our own impact while still enjoying growing plants.

Over-consumption of plants is a big issue. It’s so easy to get overexcited when you see all these incredible plants, and you can end up carrying home huge numbers of them.    2     The more plants you have, the more limited your time and resources become, and plants can suffer. This leads to another issue-many people may end up throwing away their plants which don’t look perfect or stop flowering, in a similar way to the world of fast fashion.     3    .

If you are ready and able to increase your collection, propagate(繁殖) from your own plants rather than buying more, and share plants with others.     4    Meanwhile, we can build a community of like-minded, passionate plant people.

Recycling takes a huge amount of input, which can end up more damaging to the environment, so instead of buying something of lower quality that needs replacing every year, buy fewer things of a higher quality.     5    And they can be passed down the generations.

A．But large collections call for an enormous amount of work.

B．Many commercial growers continue to market their produce.

C．This removes the need to buy plants and encourages a sharing culture.

D．These will last many years and be more cost-effective in the long term.

E．So it’s important to assess your collection and buy plants you have time to look after.

F．Throwing them away will greatly reduce your gardening footprint on the environment.

G．Many large-scale growers have used technology to minimize their impact on the environment.

3 . On the streets of Manhattan and Washington, D. C., in neighborhoods in Seoul and parks in Paris, ginkgo (银杏) trees are losing their leaves in reaction to the first gust of cold winter air. This leaf drop, gradual at first, and then sudden, carpets streets with golden, fan-shaped leaves. Scientists are documenting evidence of the event happening later and later, a possible indication of climate change. But the story of ginkgos is not the familiar one of human carelessness with nature.

Thanks to fossils found in North Dakota, scientists found a ginkgo has genetically similar ancestors dating back 170 million years to the Jurassic Period. “It almost went extinct. Then humans rescued it and spread it around the world. It’s such a great evolutionary (进化) and cultural story,” says Peter Crane, a ginkgo expert.

One theory for the decline of the ginkgo species began 130 million years ago, when flowering plants began spreading. They grew faster and attracted more pollinators (传粉者) than ginkgos. “It’s possible that ginkgos were elbowed out of the way,” says Crane. Already competing to survive, ginkgos began to disappear during a time of global cooling that began around 66 million years ago. By the time the last ice age ended 11,000 years ago, the remaining survivors were found in China.

Ginkgo trees are smelly. “My guess is that they were eaten by animals that liked smelly things. They then passed through their body and grew.” Crane says. Those same seeds may have helped ginkgo find favor with humans 1,000 years ago. Once cleaned of their outer layer, ginkgo seeds are safe to eat. It’s then, when the trees had long since disappeared elsewhere, that people in China may have begun planting them and eating their seeds. Then gradually ginkgos spread across the world. Now it’s seemingly naturally resistant to insects and high levels of air pollution.

Crane isn’t worried about its future, though: The popularity of the species will help it survive. “Though its status in the wild may be difficult to access, it’s a plant that’s unlikely to ever go extinct,” he says.

1. What may have caused the further delay of ginkgo’s leaf drop?

A．The colder weather in winter.

B．The protection from city councils.

C．The global warming phenomenon.

D．The careless interaction with humans.

2. What does paragraph 3 mainly talk about?

A．The reasons why ginkgos almost died out.

B．The advantages of ginkgos over other plants.

C．The theories of experts for multiplying ginkgos.

D．The competition between various flowering plants.

3. What might have contributed to ginkgos’ survival?

A．Their eatable seeds.	B．Their unpleasant smell.
C．The natural evolution.	D．The careful planting.

4. How does Crane feel about ginkgos’ future?

A．Worried.

B．Optimistic.

C．Uncertain.

D．Hopeless.

4 . This is the time of year when many gardeners are harvesting tomatoes. Gardening expert Jessica Damiano recently reported about the many pictures of strangely shaped tomatoes sent to her from fans of her gardening advice.     1    . The good news, Damiano said, is that there is nothing wrong with the strangely shaped fruits.     2    . Their unusual appearance does not affect their taste or nutritional value.

    3     If you have ever cut open a tomato, you know they are divided into internal (内部的) parts, called locules (小室). Most tomatoes have about four or five locules; other kinds of the fruit, like cherry tomatoes, contain two or three. But when a plant experiences extreme (极端的) temperature, cell division in the developing fruit can go off track. Temperatures over 32℃ during the day and 27℃ overnight can lead the tomato to form an extra locule. But there is not enough room inside a tomato for the extra part, so it grows on the outside of the fruit.

Not every tomato on an affected plant will be deformed (改变形状), however. What are the possibilities? Under the right conditions (temperatures that are too hot or even too cold), this could affect one or two tomatoes per plant, depending on where they are in the development process and what the (weather) conditions are, said Timothy McDermott, a professor at Ohio State University. The possibility of one of your tomatoes developing a locule oddity (怪异) is about one in a thousand, McDermott said.     4     But, Damiano noted, heirloom (原种) kinds seem more likely to have this genetic mutation (基因变异) than hybrids.

And, when harvesting your crop, remember:     5    

A．select the good-looking ones.

B．Any tomato can grow an extra locule.

C．the funny-looking tomatoes taste just as good!

D．What causes the unusual appearance of tomatoes?

E．Unless otherwise diseased, they are perfectly good for eating.

F．She said people sometimes question if the tomatoes are okay to eat.

G．Provide shade for your plants when temperatures are predicted to remain above 32℃.

5 . “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.

2. What is the algorithm used for in the research?

A．To record the sounds.	B．To control the sounds.
C．To produce the sounds.	D．To identify the sounds.

3. What has been proven by scientists according to the passage?

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.

4. Which of the following is the best title of the text?

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

6 . 阅读下面短文, 在空白处填入1个适当的单词或括号内单词的正确形式。

The Amazon rainforest is home to a great     1    (various) of plant life; however, its soil is    2       (surprising) poor in nutrients. In fact, the soil in the region cannot support agriculture for more than a few years. If a scientist is shown a report     3    (list) the nutrients of that soil, he or she will probably think that only desert plants can survive in it! Then why is the soil so poor in nutrients? For one thing, the rainy season has     4     impact on the soil. In this season, the water level can rise to more than 12 meters.     5     the water goes away, it takes away the nutrients in the soil. For another thing, due to the Amazon’s hot climate, it is difficult for the soil     6    (build) enough nutrients. Dead plants and animals     7    (break) down more quickly. The nutrients are soon taken in by the roots of the plants deep     8     the ground. As a result, most of the forest’s nutrients are locked up in the plants     9    (them), thus allowing them to grow at a(n)    10    (believable) speed.

7 . Kew Gardens is not only a popular tourist destination in London, but also a botanic garden and a research center that has the largest collection of living plants at a single site. So, let’s explore the Royal Botanic Gardens with CGTN’s reporter Robyn Dwyer.

Palm House

The first stop is the Palm House, a giant indoor rainforest with a wide range of plants. Visitors can enjoy these exotic plants while researchers can study the secrets of these flora. Eatable plants such as cocoa tree and African oil palm are all preserved here to keep the diversity of food resources. At the same time, it houses many medical use plants, including some that are used to treat cancer.

Temperate House

Known as the world’s largest Victorian glasshouse, the Temperate House is home to1,500 species of plants from temperate regions of the world. Some of the species kept here have gone extinct in the wild, such as Encephalartos woodii, a cycad from South Africa. And some are already extinct like Saint Helena olive, but the Kew has stored its DNA.

Mediterranean Garden

In the Mediterranean Garden, one can see plants from the Southern Europe, such as rosemary, olives and cork oak. Walking in the garden, one can feel the non-indoor vibe (氛围) of the Mediterranean and learn about the economic as well as scientific uses of these plants.

On International Day for Biological Diversity this year, join CGTN to travel around the world’s national parks and reserves across seven continents. Our next program is to visit penguins and seals in the Antarctic Ice Aquarium Norway. Please stay tuned!

1. What do the three stops have in common?

A．They store plants for medical use.

B．They have plants of economic value.

C．They house plants of seven continents.

D．They own plants for scientific research.

2. Which one suits a visitor preferring outdoor sites?

A．Palm House.	B．Temperate House.
C．Antarctic Ice Aquarium.	D．Mediterranean Garden.

3. Where is the text most probably taken from?

A．A botanic dictionary.	B．A TV travel series.
C．A trip advertisement.	D．A biodiversity essay.

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.

2. What is John Francis’ attitude towards the map?

A．Doubtful.

B．Disapproving.

C．Indifferent.

D．Favorable.

3. What do Reiner and his colleagues expect to do?

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.

4. What is probably the best title?

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 . Welcome to Science on Sundays

Science on Sundays is a programme of free monthly science talks which always brings the latest discoveries in plant science, as well as research linked to the plant collection at the Botanic Garden, to the visitors in a 30-minute short period of time. The programme in April is about tulips(郁金香).

Introduction

Time: 2:30 pm on Sundays

Title: In Search of Wild Tulips

Objects: adults and children aged 12+

Speaker: Brett Wilson at University of Cambridge

Background Information

The planted tulips are a common sight in spring gardens around the world, but have you ever considered where wild tulips grow? The wild ancestors of our much-loved gardening varieties can mostly be found in the mountains and valleys of Central Asia, far from the Netherlands, where most tulips are grown and bred. At the Botanic Garden, we have a National Tulip Collection where we grow many wild species including plenty of species from Central Asia. Over the last four years, Brett Wilson has been using something learned from books and combining with fieldwork to understand the diversity of tulips, with a view of identifying which species are most at risk of extinction.

Come and listen to Brett speak about the research and the adventures that have occurred in our search to find and protect wild tulips in this remote corner of the world. These will be live face-to-face talks taking place in the Botanic Garden Classroom for those visitors with interest.

1. What do we know about Science on Sundays?

A．It focuses on plants.

B．It is a paid programme.

C．It appeals only to children.

D．It is a live broadcast on weekdays.

2. How does Brett Wilson understand tulips’ diversity?

A．By making assumptions.

B．By picking and collecting tulips.

C．By growing tulips in greenhouses.

D．By combining theory and practice.

3. What is the main purpose of the last paragraph?

A．To ask visitors to plant more tulips.

B．To call on visitors to listen to the talks.

C．To push visitors to take more botany classes.

D．To advise visitors to take adventure in remote areas.

10 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Scientists in Florida have     1     (successful) grown plants in moon soil collected during NASA’s Apollo missions (任务) in the 1960s and 1970s.

    2     NASA-supported study at the University of Florida used soil collected by astronauts    3     (grow) Thale Cress 2 (拟南芥). To compare results, plants were also grown in Earth soil    4     was made to be similar to moon soil. The researchers     5     (add) water and then seeds to the soil, as well as daily nutrients (营养物). After just two days, their growth started.

According to Professor Anna-Lisa Paul, all the plants looked the same     6     the sixth day. After the sixth day,     7    , it was clear that the plants growing in moon soil were not as healthy as those growing in Earth soil.

DNA testing showed that those Thale Cress 2     8     (plant) in the moon soil were under stress. It was also found that the plants grew in different ways in soil from different parts of the moon. The soil collected during the Apollo 11 mission had been on the moon’s surface several billion years     9     (long) than the other soil, and the plants grown in it were the weakest.

NASA Administrator Bill Nelson believes this research will help future space missions and that resources on the moon and Mars     10     (need) to develop food for astronauts living and working in space.