1 . Some of the oldest living things on our remarkable planet are trees. The record holders are bristlecone pines (狐尾松) of the western United States, quite a few of which are known to be more than 3,000 years old. One individual, discovered in 2012, is estimated to be more than 5,060 years old, making it the oldest known non-clonal tree in the world!
So, how do trees survive for thousands of years?
The other part of the answer has to do with how trees age. In fact, there is quite a debate about whether ancient trees can be considered “immortal (永生的)”. That is, will such trees ever die if they are not killed by an outside force? We may never know the answer to that, but, at the very least,
Older trees benefit greatly from having bodies made mostly of dead woody tissue. In fact, an old tree might be as much as 95 percent dead tissue! Given that it isn’t alive, wood does not require metabolic (新陈代谢的) activity to maintain it,
| A．so an old tree doesn’t really need to do much to keep living |
| B．This is a question that has something to do with the good luck of trees |
| C．However, bristlecones are certainly not alone in terms of the oldest creatures |
| D．This is a fascinating question for biologists that does not yet have a settled answer |
| E．What’s more, some ancient trees have superior chemical defenses against pests and diseases |
| F．which means that trees can survive everywhere without being limited by external and internal conditions |
| G．we know that ancient trees age in ways that are dramatically different from the ways that most animals and even other plants age |
2 . 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. |
3 . When micro-plastics end up in farm fields, the pollution can damage plant growth. But two young researchers now report that combining fungi (真菌) with certain farm wastes can partly overcome that problem.
May Shin, 20, and Jiwon Choi, 18, met in a research design class at the Fryeburg Academy, a high school in Maine. May had desired to explore how micro-plastics might affect the ecosystem. Jiwon was crazy about plants and fungi. The young scientists cooperated to test how long-lived plastics might affect farm crops.
Scientists have shown certain fungi can aid root growth and a plant’s nutrient uptake. Those organisms are named arbuscular mycorrhizal fungi (AMF). Certain farm wastes, like straw, can provide nutrients to plants and help stabilize their roots. Such wastes are also known as mushroom substrate (基质) and people often grow mushrooms in them.
May and Jiwon planted over 2,000 scallion (大葱) seeds in pots of soil. Half the seeds got soil polluted with micro-plastics. The rest grew in plastic-free soil. The plants then were further divided into four groups. The young scientists added AMF to the soil in one group. Another group had a top layer of mushroom substrate. A third group got both treatments. The last group got none. For three weeks, the pair tracked how many scallions sprouted (发芽) in each group and measured the plants’ height once each week.
About twice as many scallions sprouted in clean soil compared to that containing plastic bits. But among plants surviving in the polluted soil, a combination of AMF and mushroom substrate helped them out. Those getting both treatments grew 5.4 centimeters per week. That was faster than either of the treatments alone or those getting none.
Jiwon and May then looked at the plant roots with a microscope. Where AMF had been added, it grew into those roots. That increased the scallion roots’ surface area, May said, which should promote their uptake of nutrients. So “I see this project as coming up with a sustainable solution for plant growth in polluted soils,” said May.
1. Why did May and Jiwon work together?| A．To see the effects of long-lived plastics on farm crops. |
| B．To find the relationship between plants and fungi. |
| C．To design a research on the growth of plants. |
| D．To explore the way that the ecosystem works. |
| A．To prove the existence of micro-plastics. | B．To compare fungi with farm wastes. |
| C．To tell the advantages of farm wastes. | D．To provide some related information. |
| A．Its purpose. | B．Its design. | C．Its findings. | D．Its reasons. |
| A．By keeping the plants more resistant to pollution. | B．By allowing the plants’ deep area more freedom. |
| C．By making nutrients more available to the plants. | D．By exposing the roots to a larger surface area. |
4 . How to Grow, Eat Sunflowers
Sunflowers are huge plants with bright yellow flowers. They have a long history in North America. There is evidence that they were used for food and medicine by Native Americans beginning around 1000 B. C.
How to Grow
If you start growing sunflowers from seeds, put them in room-temperature water for 2—8 hours before planting to start the growing process.
As the plants grow, they will develop long roots that work their way deep into the ground.
Mix a large amount of compost (堆肥) into the soil where the plant will grow. Compost provides important, lasting nutrients that will help the plants all seasons long.
How to Eat
To gather the seeds, wait until the plants die back and the flowers start to fall at the end of the season.
Sunflower seeds may be eaten cooked or uncooked. To roast the seeds, you need an oven. Set the temperature to 165 degrees Celsius. Once the oven is heated, cook the seeds until they are brown.
| A．Water the plants when the soil dries. |
| B．The seeds will start coming out of the head. |
| C．The process takes anywhere from 15 to 30 minutes. |
| D．Get ready to provide about 2.5 centimeters of water a week. |
| E．As a result, before planting, it is important to loosen the soil. |
| F．Remove the seeds by rubbing flowers with your hands or a hard brush. |
| G．Plant each seed into dirt 2.5 centimeters deep and 15 to 30 centimeters apart. |
5 . What if someone told you about a kind of grass as tall as the tallest trees? A grass as strong as steel? Would you believe that person? You should, for that grass is bamboo (竹子), which has more than 1,000 uses. It is not just a material for making useful products. Young bamboo is eaten, often mixed with other vegetables.
Bamboo grows in many parts of the world. In the USA it grows in many states like Virginia and Florida. Most bamboo, however, is found in wet and warm climates, especially in Asia and on the islands of the South Pacific Ocean.
In most Asian countries, bamboo is nearly as important as rice. This unusual material is used to not only build large buildings but also make water pipes, musical instruments and paper. There are over 1,000 kinds of bamboo. No wonder the lives of nearly half the people on earth would change greatly if there were no longer any bamboo.
1. According to the text, bamboo is actually a kind of .| A．grass | B．steel | C．tree | D．vegetable |
| A．Only in Asia. | B．Only in the USA. |
| C．In wet and warm climates. | D．All over the world. |
| A．Build large buildings. | B．Make water pipes. |
| C．Make musical instruments and paper. | D．All of the above. |
| A．Over 1,000. | B．Over 800. | C．Over 600. | D．Over 400. |
6 . Saving Seeds for Next Year’s Flower Garden
Just like vegetable seeds (种子), you can save flower seeds from your garden this year to plant in the following year.
If you want the same kind of flower or plant for next year’s garden, collect only the seeds from plants marked as “heritage”.
Even if you expect plants to be the same as their parents, it is not certain. Wind or insects could bring pollen from one plant to another and accidentally create a mixture.
Just like everything else in gardening, timing is important. Collect seeds on a dry, sunny day.
For plants like sunflowers, cut the head off the plant and drop it into a paper bag.
You can place the seeds in a glass box that can be sealed. Then store them in a cool, dry area. Make sure to mark your glass box so you do not forget what they are.
| A．Keep an eye on some flowers. |
| B．Let the seeds grow and fall naturally. |
| C．Give the bag a shake to help separate the seeds. |
| D．When stored with care, seeds are good for several years. |
| E．These kinds of plants will grow just like their parent plant. |
| F．In this case, add more seeds to the soil to make sure that some will grow. |
| G．You can avoid this by planting only the plant from which you plan to collect seeds. |
7 . Triantha Occidentalis, commonly known as the western false asphodel (西部假水仙), which has been known to science since 1879, is a herb-like plant found in abundance along North America’s West Coast. But it is only recently that researchers discovered the innocent-looking plant’s desire for insects.
“We had no idea it was carnivorous (食肉的),” says botanist Sean Graham. “This was not found in some exotic tropical location, but really right on our doorstep in Vancouver. You could exactly walk out from Vancouver to this field site.”
While studying the plant, the researchers noticed that Triantha Occidentalis lacked the same gene as other carnivorous plants. Since the plant grows in the same wet, sunny habitat with nutrient-poor soil as other carnivorous plants, they wondered if it caught insects for nutrition as well. “And at the same time they have sticky stems (茎),” Graham said. “So, I wonder if this could be a sign that it might be carnivorous.”
To test whether it is carnivorous, scientists marked fruit flies with nitrogen-15 isotopes (氮-l5同位素). By collecting the plants the fruit flies visited and comparing the nitrogen levels of different plants, the researchers found that Triantha Occidentalis was able to get more than half of the nitrogen it needed, suggesting that it absorbs nitrogen from the fruit flies. Additionally, the digestive enzyme (消化酶) released by the sticky hairs in flower stems was similar to that found in other carnivorous plants.
Usually, the deadly trap of carnivorous plants grow far away from the flower to prevent accidentally killing pollinators (授粉者), while the western false asphodel traps insects near flowers. The scientists say this is the first time they have met the deadly trap on the flower’s stem, and the sticky hairs on the stem of Triantha Occidentalis can only catch small insects, not the larger bees or butterflies involved in pollination.
“It’s a good reminder that we still don’t know much about the ecology of a lot of individual plant species, even in well-known environments,” says Dr. Qianshi Lin.
1. What does Graham stress in paragraph 2?| A．The discovery is made in the local place. |
| B．Carnivorous plants grow in the hottest places. |
| C．Triantha Occidentalis is very common. |
| D．Vancouver is home to various carnivorous plants. |
| A．The nitrogen. | B．The digestive enzyme. |
| C．The flower. | D．The nutrition. |
| A．Its fruit. | B．Its leaves. |
| C．Its stem. | D．Its roots. |
| A．A new species of local flower is discovered. |
| B．A carnivorous flower in the wild grows well. |
| C．A flower gives off strange smell to attract insects. |
| D．An innocent-looking plant turns out to be carnivorous. |
