1 . In early October, Travis Gienger transported an enormous pumpkin (南瓜) from his home in Minnesota to the World Championship Pumpkin Weigh-Off in California. His pumpkin set the record for the biggest one ever grown in North America. How do competitive growers get their pumpkins to grow to massive sizes?
Gienger, who teaches horticulture (园艺学) at Anoka Technical College, begins growing his pumpkins in mid-April, starting with seeds that he grows indoors for the first few weeks, when Minnesota’s soil is too frosty.
Depending on the variety, pumpkin plants can grow up to a dozen fruits on a single vine (藤曼) . But to maximize size, growers remove all but one or two of these pumpkins in order to decrease each individual fruit’s competition for resources.
But what exactly happens inside a pumpkin as it grows? Two factors drive natural growth: cell division and cell expansion. Cell division accounts for most of the growth at the beginning of a fruit’s life. This period lasts for about 20 days in pumpkin plants.
A.Biology has the answers. |
B.Genetics also influences pumpkin growth. |
C.The following tips will give you a head start. |
D.Once it warms up, the plants are transferred outside. |
E.When it stops, cell expansion will then come into play. |
F.Growers extend the growth period for as long as possible. |
G.Growers also remove the weeds in the area for the same reason. |
2 . Four surprising ways algae (藻类) are driving innovation
Algae can be a double-edged sword. Increased human activity and climate change have caused explosions of algae populations in water bodies around the world sometimes choking entire ecosystems of sunlight and oxygen. Even though they are so closely associated with humanity’s negative impact on Earth, algae could also play key roles in helping fight pollution, viruses, and more.
Filtering (过滤) water.
With microplastic pollution documented in almost all water bodies, a recent study shows that through absorption, algae can help filter microplastics out of water.
Fueling air travel.
Fighting viruses.
Red algae can prevent the replication (复制) of some viruses, including COVID-19, according to a 2020 study.
In 2019, freshwater algae were launched into space to turn the carbon dioxide exhaled (呼出) by astronauts on the International Space Station into oxygen. Since algae are also high in protein, they could replace up to 30 percent of astronaut food in the future.
A.Making space food more nutritious. |
B.Making long-term space travel possible. |
C.These are several ways algae are solving modern problems. |
D.Some algae can also filter chemicals that can be used in fertilizers. |
E.Brown algae have been shown to stimulate the body’s immune system. |
F.Algae can produce more effective biofuels than traditional sources like soybeans. |
G.It aims to harvest algae for energy while keeping the environment pollution-free. |
1. What kind of area do Bill and Sally live in?
A.A hot area. | B.A high area. | C.A dry area. |
A.They are gardeners. | B.They are designers. | C.They are builders. |
A.Trees. | B.Glass houses. | C.Fences. |
A.Successful. | B.Unsatisfactory. | C.Impossible. |
The use of bamboo in science and technology is really exciting. In the Warring States period, Li Bing
Papermaking
In the Yuan dynasty, a man
5 . Every tree tells a story. They hold our memories, represent belief, and witness countless moments of joy and sorrow. In our imagination, there is always a place for a tree.
For the locals in Naunde, Mozambique, a mango tree provides more than just shade from the Saharan sun. It is also a traditional setting for storytelling, ceremonies, and regulating village life. “It is a place to meet and talk, to seek agreement and settle arguments, to bridge differences and develop unity,” wrote Kofi Annan, the former Secretary-General of the UN. “If you have a problem and can’t find a solution, you meet again tomorrow under the tree and you keep talking.”
The mango tree always stands there, witnessing and remembering everything, and at the same time becomes an inseparable part of the collective memory of the locals. “Each growth layer that trees add every year contains a bit of the air from that year. The trees absorb carbon dioxide from the air through tiny pores (气孔) , which helps build their tissues, so they physically hold the record of the years of their surroundings,” said Benjamin Swett, author of New York City of Trees. In this way, trees also serve as nature’s memory stick, keeping a record of a history as long as themselves.
The English language borrows a lot from trees: We turn over a new leaf and branch out, meaning we move on from the past and start something new. And there are times when we can’t see the wood for the trees. We tend to enjoy the flourishing leaves, branches, and roots of the trees. However, we pay little attention to the forests that embrace trees. The same things often happen to us in our own lives. We often dip ourselves into some bad experiences in life. As a result, we may give up at a terrible moment instead of imagining satisfying success after defeating the failure.
Trees inspire mankind, not just through language, but through ideas. Perhaps the most famous is a tree in a garden in Lincolnshire, England, where an apple fell and inspired young Isaac Newton to wonder: Why would that apple always fall directly to the ground? According to an 18th-century account, Newton was home from Cambridge when he stepped into the garden and into a reverie (沉思) . There, the idea of gravitation came into his mind, inspired by an apple.
1. What is the role of a mango tree in Naunde?A.A spot to bind the locals together. | B.A witness to the changing weather. |
C.A generous food supplier on Earth. | D.A shelter to protect villagers in disasters. |
A.By changing the width of their growth layer. |
B.By sticking out branches in different directions. |
C.By absorbing carbon dioxide to build their tissues. |
D.By reflecting changing climate conditions with their tiny pores. |
A.Suggestions on facing failure. | B.Famous English stories about trees. |
C.The relationship between trees and forests. | D.Lessons from English expressions related to trees. |
A.To explain the necessity of observation. | B.To show how gravitation was discovered. |
C.To stress the importance of trees in inspiring ideas. | D.To introduce how trees serve as a mirror of history. |
6 . Cork is a light brown material harvested from the cork oak tree. Cork is lightweight, strong and resistant to water.
The cork oak tree is native to the western Mediterranean coast of Europe.
Because cork oak trees are not killed during harvest, they can live for as long as 200 years. Also, used cork products can be recycled and used again. This makes cork a valuable renewable resource.
A.After drying, the cork is ready to be cut. |
B.Harvests only happen once every nine years. |
C.Cork has even found a use in making rockets. |
D.It is best known for keeping liquids from spilling. |
E.Cork can be shined and used to cover floors and walls. |
F.The largest cork oak forests in the world are in Portugal. |
G.The wine industry has been a major supporter of cork production. |
7 . Common water plant could provide a green energy source. Scientists have figured out how to get large amounts of oil from duckweed, one of nature’s fastest-growing water plants. Transferring such plant oil into biodiesel (生物柴油) for transportation and heating could be a big part of a more sustainable future.
For a new study, researchers genetically engineered duckweed plants to produce seven times more oil per acre than soybeans. John Shanklin, a biochemist says further research could double the engineered duckweed’s oil output in the next few years.
Unlike fossil fuels, which form underground, biofuels can be refreshed faster than they are used. Fuels made from new and used vegetable oils, animal fat and seaweed can have a lower carbon footprint than fossil fuels do, but there has been a recent negative view against them. This is partly because so many crops now go into energy production rather than food; biofuels take up more than 100 million acres of the world’s agricultural land.
Duckweed, common on every continent but Antarctica, is among the world’s most productive plants, and the researchers suggest it could be a game-changing renewable energy source for three key reasons. First, it grows readily in water, so it wouldn’t compete with food crops for agricultural land. Second, duckweed can grow fast in agricultural pollution released into the water. Third, Shanklin and his team found a way to avoid a major biotechnological barrier: For the new study, Shanklin says, the researchers added an oil-producing gene, “turning it on like a light switch”by introducing a particular molecule (分子) only when the plant had finished growing. Shanklin says, “If it replicates (复制) in other species-and there’s no reason to think that it would not — this can solve one of our biggest issues, which is how we can make more oil in more plants without negatively affecting growth.”
To expand production to industrial levels, scientists will need to design and produce large-scale bases for growing engineered plants and obtaining oil — a challenge, Shanklin says, because duckweed is a non-mainstream crop without much existing infrastructure (基础设施).
1. What can people get from duckweed firsthand?A.Plant oil. | B.Stable biodiesel. |
C.Sustainable water. | D.Natural heat. |
A.Options for renewable energy. |
B.Reasons for engineering genes. |
C.The potential of revolutionary energy source. |
D.The approach to avoiding agricultural pollution. |
A.Industrial levels. | B.Unique design. |
C.Academic research. | D.Basic facilities. |
A.Duckweed Power | B.Duckweed Production |
C.Genetic Engineering | D.Genetic Testing |
1. What are the good seeds confirmed by?
A.Containers. | B.X-rays. | C.Freezers. |
A.To be preserved for long. |
B.To tackle climate change. |
C.To safeguard food supply. |
A.Where seeds are stored. |
B.How the seed bank works. |
C.Why seed banks are important. |
9 . 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. |
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. |
A.Spread. | B.Change. | C.Existence. | D.Self-repair. |
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. |
10 . The green and red watermelon is a sweet, refreshing summer snack. But it wasn’t always so sugary or brightly colored. So what did watermelons originally taste and look like, and from where did they come?
The fruit isn’t from the Fertile Crescent of ancient Mesopotamia, as so many other domesticated (家养的) crops are, research shows. Susanne Renner, a scientist, and her colleagues carried out comprehensive genetic sequencing (基因测序) of the domesticated watermelons — the kind you might find on supermarket shelves — along with six wild watermelon species.
“We found the modern genomes (基因组) of the domesticated watermelon are more closely related to the Sudanese wild type than any other that we analyzed,” she said. The Sudanese wild watermelon has some obvious differences from the domesticated version. “The flesh is white and not very sweet, and it’s mainly used as animal feed,” Renner said. Nevertheless, the genetic similarity between the two species led the researchers to conclude that the Sudanese fruit is probably a precursor (前身) to the red and sweet domesticated watermelon.
It’s likely that ancient farmers grew non-bitter varieties of the wild watermelon and thus increased its sweetness over many generations through the domestication process. The red color is probably also thanks to artificial selection, in which farmers likely favored and selectively bred red fruit.
We already knew that the ancient Egyptian king Tutankhamun was buried with watermelon seeds 3,300 years ago, yet that isn’t sufficient proof of a domesticated, sweet watermelon. But then, Renner found an image of a watermelon-like fruit on an ancient Egyptian tomb painting, thought to be more than 4,300 years old. In a separate tomb, another image showed the watermelon cut up in a dish alongside other sweet fruits. This realization, coupled with Renner’s genetic findings, suggests that the watermelon was most likely domesticated around that time either in Egypt or within trading distance of the ancient empire.
“Historically speaking, that’s a very significant finding,” said Hanno Schaefer, a professor of plant biodiversity. “It’s becoming clearer that we’ve greatly neglected the North African region. We’ve focused too much on the Fertile Crescent and we need to invest more resources into studying the agriculture of North Africa.”
1. What can we learn about the Sudanese wild watermelon?A.It is brightly colored and sugary. |
B.It is consumed mainly by animals. |
C.It has no connection with the domesticated type. |
D.It has more differences than similarities to the domesticated type. |
A.More resources will be devoted to agriculture research in South Africa. |
B.The domesticated watermelon has a history of at least four thousand years. |
C.The domesticated watermelon probably developed from the Sudanese type. |
D.Few domesticated crops are from the Fertile Crescent of ancient Mesopotamia. |
A.The history of the Sudanese wild watermelon. |
B.Where wild watermelons actually come from. |
C.The characteristics of domesticated watermelons. |
D.How domesticated watermelons came into being. |
A.Favorable. | B.Doubtful. | C.Critical. | D.Tolerant. |