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VOL 17 – THE ECONOMIST – KING BIBI – V17.1 PEST CONTROL- A BUG IN THE SYSTEM

THE ECONOMIST- 1 trong 3 tạp chí thường được chọn để ra bài Reading trong IELTS.


__—- VOCABULARY –__

  1. Irritant (n): a substance that makes part of your body sore or painful (chất kích thích)
  2. Troublesome (a): causing a lot of problems for someone (khó chịu, phiền hà)
  3. Whitefly (n): are small Hemipterans that typically feed on the undersides of plant leaves (ruồi trắng)
  4. Dastardly deed: an intentiona lact that is evil and cruel (hành động đáng sợ)
  5. Ward off (v): to prevent someone or something unpleasant from harming or coming close to you (phòng tránh)
  6. Pathogen (n): any small organism, such as a virus or a bacterium that can cause disease (mầm bệnh)
  7. Infestation (n): a large number of animals and insects that carry disease, that are present where they are not wanted (sự phá hoại)
Infest (v): (of animals and insects that carry disease) to cause a problem by being present in large numbers (phá hoại)
  1. Saliva (n): the liquid produced in your mouth to keep tHe mouth wet and to help to prepare food to be digested (nước bọt)
  2. Ruse (n): a trick intended to deceive someone (thủ đoạn)
  3. Symbiotic (a): involving two types of animal or plant in which each provides the conditions  necessary for the other to continue to exist (cộng sinh)
  4. Imminent (a): coming or likely to happen very soon (sắp tới)
  5. Summon (v): to order (someone) to be present (thu hút)
  6. Deceive (v): to persuade someone that something false is the truth; trick or fool (đánh lừa)
  7. Spoof (v): to try to make someone believe in something that is not true, as a joke (lừa)
  8. Chamber (n): an enclosed space or cavity (bình)
  9. Expose to (v): to make (something) visible by uncovering it (tiếp xúc)
  10. Nymph (n): An immature form of an insect that does not change greatly as it grows (con nhộng)
  11. Biochemical mechanism: a chemical mechanism involved in vital processes occurring in living organisms (cơ chế sinh hóa)
  12. Counter measure (n): an action taken against an unwanted action or situation (biện pháp đối phó)

PEST CONTROL

A BUG IN THE SYSTEM

A pair of silverleaf whiteflies, Bemisia tabaci, which measure about one-tenth of an inch long, feed on a watermelon leaf.

How whiteflies hack the way plants communicate

When some plants are attacked by herbivores they fight back by producing irritants (chất kích thích) and toxins as their leaves get chewed up. Certain insects, however, can resist these defences. Among the best at doing this, and hence one of the most troublesome(khó chịu) crop pests, is the whitefly (ruồi trắng). Remarkably, as new research shows, whiteflies enhance their dastardly deeds(hành động đáng sợ) by hacking a biological early-warning communications system used by plants.

When whiteflies launch an attack, plants respond by producing jasmonic acid as a defence mechanism. This hormone triggers the production of compounds that interfere with an insect’s digestive enzymes, making it difficult for them to feed. But plants can produce a different substance, salicylic acid, to help ward off (phòng tránh) pathogens (mầm bệnh), such as a virus. Whiteflies trick the plant into behaving as if it was threatened with a disease rather than an insect infestation (sự phá hoại). This is possible because whiteflies have compounds in their saliva (nước bọt) that dupe plants into producing more salicylic acid and less insect-repelling jasmonic acid. This ruse (thủ đoạn) makes it much easier for them to infest (phá hoại) the plant.

Raising the alarm

Peng-Jun Zhang and Xiao-Ping Yu of Jiliang University in China, and their colleagues, wondered whether there might be more to it than that. In particular they decided to investigate what happened to the rallying cry plants make when they are under attack by insects or disease.

That idea might appear to have been lifted from the film “Avatar”, set on a fictional moon where plants communicate. But in recent years researchers have found that plants do have the ability to raise an alarm when they are threatened. Sometimes this is sent in biochemical messages via root and symbiotic (cộng sinh) fungal connections in the soil, and sometimes through chemicals released into the air.

The alarm signals give warning to nearby plants of an imminent (sắp tới) threat so that they can prepare to defend themselves. When a pathogen is causing harm, the signals drive a population-wide production of salicylic acid. If insects are the problem, the plants make jasmonic acid as well as special compounds that summon (thu hút) predators to eat the insects.

As they report in Proceedings of the National Academy of Sciences this week, Drs Zhang and Yu found that whiteflies not only deceive (đánh lừa) individual plants, making them respond as they would to a disease not an insect, but also spoof (lừa) their alarm system making them spread the erroneous message. This makes neighbouring plants more vulnerable.

To show this, the researchers set up an experiment growing tomato plants in glass chambers (bình). Some plants were infested with whiteflies and some left alone. After several days, the air from each chamber was passed into similar chambers containing a healthy tomato plant and left for 24 hours. These new plants were then infested with whiteflies. Although the number of eggs laid on all the plants was much the same, on those exposed (tiếp xúc) to the air of infested plants the new generation of whitefly nymphs (con nhộng) developed much more quickly.

The researchers ran the experiment again but this time looked closely at the compounds produced by plants exposed to the different air samples. They found that while jasmonic acid was produced at the expected high levels during a whitefly attack by plants contained in healthy air, plants exposed to air from infested plants only produced half those levels. Salicylicacid production showed the reverse trend, with plants exposed to healthy air samples before a whitefly attack producing very little of it and those exposed to air samples from infested plants producing a lot.

Given these findings, Drs Zhang and Yu argue that if the biochemical mechanism (cơ chế sinh hóa) driving plants to send out incorrect warning signals can be found, it might be possible to come up with more effective agricultural countermeasures (biện pháp đối phó). That could help farmers protect their crops from a sneaky pest that worldwide costs hundreds of millions of dollars annually.

HP ACADEMY

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