1 . When lightning caused fires around California’s Big Basin Redwoods State Park north of Santa Cruz in August 2020, the fire spread quickly. Mild fires strike coastal redwood (红杉) forests about every decade. The giant trees resist burning thanks to the bark (树皮), up to about 30 centimetres thick at the base, which contains acids. Their branches and needles are normally beyond the reach of flames. But this time flames shot through the top of 100-metre-tall trees, burning the needles. “It was shocking,” says Drew Peltier, a tree expert at Northern Arizona University. “It really seemed like most of the trees were going to die.”
Yet many of them lived. In a paper published yesterday in Nature Plants, Peltier and his colleagues help explain why: The survivors use long-held energy reserves—sugars that had been made from sunlight decades earlier—and poured them into buds (芽) that had been lying dormant (休眠的) under the bar k for centuries.
“This is one of those papers that challenges our previous knowledge on tree growth,” says Adrian Rocha, an ecosystem ecologist at the University of Notre Dame. “It is amazing to learn that carbon taken up decades ago can be used to sustain its growth into the future.” The findings suggest redwoods have the tools to cope with big fires driven by climate change, Rocha says. Still, it’s unclear whether the trees could cope with the regular infernos that might occur under a warmer climate environment.
The fire in 2020 was so intense that even the top branches of many trees burned and their ability to photosynthesize (光合作用) went up in smoke along with their pine needles. Trees photosynthesize to create sugars and other carbohydrates (碳水化合物), which provide the energy they need to grow and repair tissue. Trees do store some of this energy, which they can call on during a drought or after a fire. Although the redwoods have sprouted (长出) new growth, Peltier and other forest experts wonder how the trees will cope with far less energy from photosynthesis, given that it will be years before they grow as many needles as they had before the fire. “They’re alive, but I would be a little concerned for them in the future.”
1. What’s special about this big fire for coastal redwood forests in 2020?A.It burnt the top of the trees. | B.It was very close to the last fire. |
C.It resisted burning effectively. | D.It caused relatively minor damage. |
A.Sugars protected their barks. | B.Energy reserves promoted the growth of buds. |
C.They got used to hot climate. | D.They took in much carbon to resist fire. |
A.Unpredictable disasters. | B.Changeable climate. |
C.Terrible environment. | D.Uncontrollable fires. |
A.Their tissues can’t be repaired. | B.They can’t save energy anymore. |
C.Their energy saved is not sufficient. | D.They grow too slowly. |
2 . There are a number of animals that give off light in some way-including several kinds of insects and fish. Some kinds of mushrooms give off light, too. But most plants don’t give out light. Now, scientists are working to change that.
When a living thing gives off light, it’s called bioluminescence(生物发光). Fireflies are a well-known example of bioluminescence. Though less well-known, many mushrooms are also bioluminescent. These bioluminescent creatures light up thanks to the chemicals called luciferins(荧光素)inside their bodies. Luciferins cause a chemical reaction that can give off light.
Plants don’t naturally have luciferins, so there are no naturally bioluminescent plants. But that hasn’t stopped scientists from trying to create them. In the past, scientists have created plants that made less bright by adding DNA from shining objects. Scientists have also created plants that can give off light by adding luciferins to plants. But it only works as long as the chemicals last. In 2017, a team was able to cause a plant to give off light for about four hours.
Now, researchers at a Russian company have come up with a new method of creating shining plants. By adding certain parts of the DNA from shining mushrooms to ordinary tobacco plants, the researchers were able to create plants that could make their own luciferins. The scientists reported that the light was about 10 times brighter than in earlier shining plants.
The researchers believe that shining plants could help scientists learn more about the way plants work. For example, the moving patterns or waves of light in the plants may show activities in plants that normally can’t be seen. The shining also helps reveal how plants may be affected by things around them. For example, the plants gave off much more light strongly when a ripe banana skin was nearby. But the researchers don’t think the plants will just be used for science. They think many people may want shining plants for their beauty. So they are working with a company to develop shining plants for sale.
1. What phenomenon does the author describe in paragraph 1?A.Most animals hate giving off light. |
B.Many plants give off light through scientists’ efforts. |
C.Animals give off light to protect themselves. |
D.It’s hard to find plants that give out light. |
A.It gives off lots of heat to warm itself. |
B.It has chemical reactions inside its body. |
C.It lacks energy due to chemical reactions. |
D.It informs other fireflies of the danger. |
A.By showing numbers. | B.By making a comparison. |
C.By providing examples. | D.By making a summary. |
A.Human development results in less shining plants |
B.Scientists manage to create shining plants |
C.People’s lifestyles are reflected in shining plants |
D.Geography determines the types of shining plants |
3 . Imagine walking by a maple (枫树) tree that is no taller than a ruler. You may think that this is a special type of miniature tree, but it actually isn’t! Creating a tree like this is a form of art called bonsai. Bonsai are tiny trees grown in small pots. Bonsai can be any kind of tree. They just need to be planted in a small container and cultivated in a way that stunts their growth.
Cultivating, or taking care of, a bonsai tree requires patience and care. Pruning — removing branches, leaves, and roots — is an important part of raising bonsai. It keeps the trees small, and it also controls their shape. Pinching off new buds (嫩芽) and tying wire around branches help create a beautiful design. These processes allow the grower to control what shape the bonsai tree will take as it develops.
People who raise bonsai want their trees to look like they belong in nature. Even though it is contained in a pot, a bonsai tree should look similar to its larger counterpart (相对物,参照物). For example, the bonsai maple should have the same forked branches and vibrant leaves as the full-sized maple. This makes the bonsai a tiny copy of the full-sized maple that towers overhead.
Like other plants, bonsai need water and food from the soil. In order to keep bonsai the proper size, you need to carefully control the amount of water and fertilizer you provide. If you want to grow a bonsai, it is best to start with a species that grows in your area. Most bonsai do best when kept outdoors, so they need to be able to survive the weather. If kept indoors, the bonsai must be placed near a window. Interestingly, with proper care, bonsai can live for a hundred years or more.
1. Why does a bonsai tree need pruning frequently?A.To control its size. |
B.To help it grow well. |
C.To save fertilizer and water. |
D.To create a shape as designed. |
A.One of a larger counterpart. |
B.A tiny copy of the full-sized maple. |
C.One looking like its counterpart in nature. |
D.One with forked branches and vibrant leaver. |
A.To keep the bonsai indoors. |
B.To start with a native species. |
C.To keep bonsai the proper size. |
D.To control the amount of water. |
A.Bonsai — a special hobby |
B.How to be bonsai grower |
C.What does bonsai refer to? |
D.Why is bonsai so popular? |
4 . Four Best Plants to Give as Gifts
Choosing a gift for someone is always a challenge. Giving plants is one way to try if the recipient is already a plant-lover. Here are some sure to impress as thoughtful gifts.
Jade Plant
The jade plant is a large succulent (肉质植物) that makes a perfect gift for someone who’s mastered parenting succulents. With a woody stem (茎), it looks like a tree once growing tall enough. Besides occasional watering and a bright window, the jade plant has few other requirements. A good challenge for ambitious owners is to regularly cut off its heavy leaves to reduce weight.
Christmas Cactus
This is a succulent with eye-catching flowers that appear in winter. You might assume it a picky plant, but nothing could be further than the truth. It prefers bright, indirect light and grows well in average potting soil. This plant prefers a steady watering schedule, especially in winter. To encourage more growth, plant it in a hanging container that allows its branches to hang down.
Paperwhite
Some people just aren’t interested in keeping houseplants around long-term, and paperwhite flowers are an excellent gift for anyone you know who fits this mould. Paperwhites grow from bulbs (鳞茎) and will produce flowers out of season. The roots need to be kept relatively damp, but once they are blooming (开花), there’s not much that can go wrong. They can be replanted outside after they have run their course.
Corn Plant
The corn plant is forgiving of variable light conditions and watering routines. It grows slowly, but can reach a height of four to six feet, and can make an impressive floor plant. Its leaves turn paler in direct sunlight to reflect the extra light, and darker green in shady conditions to maximize sunlight absorption.
1. Which plant requires practised gardening experience?A.Jade plant. | B.Christmas cactus. | C.Paperwhite. | D.Corn plant. |
A.By replanting it outside before blooming. | B.By watering it regularly during blooming. |
C.By cutting off most of its heavy leaves. | D.By making its branches grow upwards. |
A.The frequency of watering. | B.Its flowering time. |
C.Its rate of growing. | D.The amount of sunlight. |
A.From not enough water. |
B.From not enough sun. |
C.From not enough plant food. |
6 . It’s breathtaking to watch the delicate spring wildflowers come out from their blanket of leaves, bloom, develop and disperse (传播) fruit, all in a matter of a few short days or weeks.
Although they look fragile, these are tough little plants, each focusing its efforts on spreading its species. They have evolved to have a wide range of flower structures and colors, some with fragrances, attracting many different insect species to assist them in pollination (授粉).
There is one strategy (策略) that a surprising number of spring blooming native plants have evolved in common: seed dispersal by ants. As many as thirty percent of the spring flowering plant species in the forests of eastern North America have evolved to take advantage of this situation to benefit themselves. These species have evolved to provide food attached to their seeds to encourage ants to disperse those seeds. This food, called an elaiosome, is a specialized fat body whose chemical composition more closely matches that of the insects that ants prefer than it does that of a seed.
When a fruit opens to disperse its seeds, the elaiosomes are an instant attraction for ants. They take the seed with its attached elaiosome back to their nests for consumption there, but they just eat the elaiosome, their preferred food, and dispose of the seed on their trash pile. This tends to be an environment that is rich in nutrients, and will benefit the growth of the new plant. Just to make sure the ants don’t eat the seeds in addition to the elaiosome, some plant species have hard seed coatings that ants can’t really bite through.
This evolutionary adaptation is somewhat similar to the strategy of plants that have evolved to surround their seeds with fleshy fruits to attract birds to assist them with seed dispersal. Given the fact that there are fewer birds available in early spring to help with seed dispersal, it makes sense that the early blooming plants evolved to partner instead with the ants for this service.
Did you ever wonder how your Spring Beauty managed to pop up in new locations in your lawn or garden? Thank an ant!
1. How many methods do wildflowers have to attract animals according to the text?A.Two. | B.Three. | C.Four. | D.Five. |
A.It’s hard to digest. | B.It’s impossible for ants to resist. |
C.It makes the earth rich in nutrients. | D.It’s often thrown into the trash pile. |
A.Ants are creative and hardworking. |
B.Ants are better at dispersing than birds. |
C.The birds in the early year are not enough. |
D.The birds are not interested in their fleshy fruits. |
A.Thank Ants for Wildflowers |
B.Wildflowers Discover Their Treasures |
C.New Species of Wildflowers are Found |
D.Ants Are Superheroes Protecting Environment |
Nature’s Lungs
We know that trees are nature’s purifier (净化器): They absorb carbon emissions (碳排放)and release oxygen. But their
According to the study, there are
This may sound like a lot,
Yet, planting trees is still considered the most effective way
From “pocket parks” between communities to forest parks in the outer cities, local governments are
From 2021 to 2022, Shanghai transformed 62 woodlands into leisure spaces. These leisure spaces open up forests,
Apart from meeting people’s needs, parks can also do good to the environment. Take Beijing’s Central Green Forest Park
9 . 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. |
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. |
A.Their eatable seeds. | B.Their unpleasant smell. |
C.The natural evolution. | D.The careful planting. |
A.Worried. | B.Optimistic. | C.Uncertain. | D.Hopeless. |
Kongeegen is a large oak tree located (位于) in the north of Denmark. Kongeegen’s real age is unknown. The tree went through a scientific study in 1965, through which Kongeegen was confirmed to be between 1,500 and 2,000 years of age. This would make it the oldest living oak in the northern part of Europe.
Granit Oak
The Granit Oak measures 2.38 meters in diameter (直径) and 23.4 meters in height. The head of the tree measures about 1,017 square meters, which covers nearly 11,000 square feet. Back in 1967, the Bulgarian government announced this oak was a protected tree and it has been under protection ever since.
Stelmuze Oak
Not all of the tree’s branches are still alive, but it continues to be considered a living tree. This makes it the oldest living tree in all of Lithuania. Stelmuze Oak was made a natural monument (纪念碑) in 1960. Ever since then, it has been on the Lithuanian list of protected monuments, and it is well looked after.
Major Oak
Local legends (传说) say that this is the tree where Robin Hood’s shelter was located. According to the tales, Robin and his merry men slept in this very tree. Back in 2003 in Dorset, England, 260 acorn saplings (橡子树苗) from the Major Oak were used to start an oak plantation.
Kongeegen | Granit Oak | Stelmuze Oak | Major Oak | |
Estimated age | 1, 500-2, 000yeas | 1,700 years | 1, 500-2, 000 years | 800-1,000 years |
Status | Alive | Dead | Alive | Alive |
Location | Denmark | Bulgaria | Lithuania | England |
Oak species(物种) | Quercus robur | Quercus robur | Quercus robur | Quercus robur |
A.In 1960. | B.In 1965. | C.In 1967. | D.In 2003. |
A.Kongeegen. | B.Granit Oak | C.Stelmuze Oak. | D.Major Oak. |
A.They are of the same species. | B.There are beautiful stories about them. |
C.Some of their branches aren’t alive now. | D.They are under good protection. |