How do plants talk to each other?
Read How do plants talk to each other? and check the IELTS Reading answers. In 1983, plant scientists Jack Schultz and Ian Baldwin reported that the leaves of young maple trees increased their defense systems when exposed to maples that had been damaged by plant-eating (herbivorous) insects. The in…
Passage preview
In 1983, plant scientists Jack Schultz and Ian Baldwin reported that the leaves of young maple trees increased their defense systems when exposed to maples that had been damaged by plant-eating (herbivorous) insects. The injured trees, they suggested, were alerting neighbors to the presence of a predator by releasing chemical signals into the air. But the plant research community did not accept this. The results were difficult to replicate, critics pointed out. Many also questioned how it could be evolutionarily stable if it benefited neighboring plants but not the plant releasing the signal. By the late 1980s, most ecologists felt that Schultz and Baldwin’s ideas had been discredited.
Vocabulary from this passage
9 words worth learning before you sit the test, each with the sentence it appears in.
- anything but adverb phrase
Not at all; the opposite of what is stated.
In the passage:
"plants are anything but uncommunicative": a strong denial, meaning plants communicate a great deal.
Synonyms: far from, by no means
- come to grips with verb phrase
To begin to understand and deal with a difficult problem or situation.
In the passage:
"results that, as a field, we need to come to grips with": Karban says scientists must deal with the findings.
Synonyms: get to grips with, deal with
- compensate for verb phrase
To make up for something lacking or harmful by doing something else.
In the passage:
"the chili plants were compensating for the presence of the fennel": they grew faster to counter its harmful effect.
Synonyms: make up for, offset
- discredit verb
To make people stop believing that an idea or person is true or reliable.
In the passage:
Q14's heading says "widespread rejection of an idea"; paragraph A says the idea "had been discredited".
Synonyms: reject, dismiss
Opposites: vindicate
- in close proximity to adverb phrase
Very near to something in distance.
In the passage:
"grown in close proximity to sagebrush plants": the plants had to be near each other for the effect.
Synonyms: very close to, right next to
Opposites: far from
- indications to the contrary noun phrase
Signs or evidence showing that the opposite is true.
In the passage:
Q15's heading says "Evidence leading to renewed belief"; paragraph B says experiments "began to yield convincing indications to the contrary".
Synonyms: evidence, signs of the opposite
- inhibit verb
To slow down or prevent the growth or development of something.
In the passage:
"chemicals that inhibit the growth of other plants": the fennel slows its neighbours.
Synonyms: hinder, restrain
Opposites: promote
- on the horizon adverb phrase
Likely to happen or arrive in the near future.
In the passage:
Q24 says research will "one day help"; Johnson says applying it "is definitely on the horizon".
Synonyms: one day, coming soon
- yield verb
To produce or give a result, such as evidence or data.
In the passage:
"experiments began to yield convincing indications": it means produce results, not give way or surrender.
Synonyms: produce, provide
Answers with explanations
- 14. iii
Paragraph A reports an early idea that was turned down: the plant research community **did not accept** it, and by the late 1980s it **had been discredited**. That matches **widespread rejection of an idea**. The heading about new evidence belongs to the next paragraph, which starts with **however**.
- 15. vi
Paragraph B opens with **A decade later, however** and says better-designed experiments gave **convincing indications to the contrary**. This is evidence that makes people believe again in the idea rejected in paragraph A, which is the heading about **renewed belief in a theory**. The paragraph describes experiments, not new technologies.
- 16. viii
Paragraph C asks why a plant would send signals at all, and one answer is that signalling **enhances the ‘extended fitness’ of the sender**. Enhancing something is a **benefit**, and **a suggested benefit to the sender** fits, because the writer says it **may have been favored**. Nothing in the paragraph blocks communication.
- 17. i
Paragraph D describes two links under the ground: distress signals passed **through the plants’ roots**, and warnings about aphids sent along fungal **networks** around the roots. Both are messages travelling **underground**, so the heading about **sending messages underground** fits.
- 18. iv
Paragraph E is built on Gagliano's study: chili plants **growing next to fennel** **developed more quickly** than chili plants grown with their own kind. One species (fennel) is making another (chili) grow faster, which is **accelerating growth in another**. The doubts about sound are only a side issue.
- 19. ii
Paragraph F begins by saying the knowledge could **eventually be applied to agriculture** and give **hardier crops**. The heading says **farmers** for agriculture and **potential advantages** for **could**. The rest of the paragraph only adds that more work is needed.
- 20. roots
Find **Ariel Novoplansky** in paragraph D. The summary's **send messages** matches **distress signals can be passed**, and *via their* matches **through the plants’**. After *their* the gap needs a plural noun: **roots**.
- 21. drought
Find the **garden pea plants in rows**. The summary's **created conditions like a** matches **subjected the first in each row to conditions similar to those experienced in a drought**. The article *a* is already printed before the gap, so write only **drought**.
- 22. fungi
Look for **Aberdeen** and Johnson's team. They study the **labyrinths of hair-like fungi** around the roots, which the summary calls **networks of ... which connect the plants**. The word *networks* is already in the sentence, so the noun to add is **fungi**.
- 23. aphids
Look for **broad bean plants** in paragraph D. They were **infested with aphids**, and the dash explains that aphids are **small herbivorous insects**, which the summary calls **plant-eating insects**. The plural form printed in the passage is **aphids**.
- 24. C
Match **improve our food supply** with **applied to agriculture**. The quoted words are said by **Johnson**: applying the knowledge is a big jump, but it is **definitely on the horizon**, which matches **one day**. The researchers in general believe it, but Johnson is the one named.
- 25. A
The statement's **internal mechanisms intended to help a single plant** matches **within-plant signaling**, which each plant uses to protect itself. The person who **agrees** and says communication **may be a result of** that process is **Karban**. Novoplansky and Johnson study how signals travel, not why they began.
- 26. B
The statement's **attitudes ... have changed greatly in recent decades** matches **Ariel Novoplansky** looking back: in the late 1980s the subject was considered **very weird**, but **today, there is no doubt**. The change in opinion is the point of his comment.