Table of Contents
BEST IELTS Academic Reading Test 514
IELTS ACADEMIC READING TEST 514 – PASSAGE – 3
IELTS ACADEMIC READING TEST – 514
READING PASSAGE – 3
Roses are blue, violets are red
If you don’t like GM food, try flowers instead
Beautiful flowers, like any other beautiful object, can separate the most sensible of people from their money. On special occasions, people invest in a display of beautiful stems and petals to signal their own feelings or intentions. The result is a cut-flower industry in which roses alone are worth $10 billion a year. But that is nothing, compared with what happened in the past. In 17th-century Holland, tulips (the fashionable flower of the day) grew so expensive that people exchanged their bulbs for houses. One bulb of the most sought-after variety, the flaming red-striped Semper Augustus, sold for twice the yearly income of a rich merchant.
For modern flower growers, the equivalent of the Semper Augustus is the blue rose, which horticulturalists have longed for since the 19th century. Any blue rose sent on Valentine’s Day this year will have been dyed. But if Yoshi Tanaka, a researcher at Suntory, a Japanese drinks company, has his way, that will soon change. Dr Tanaka is currently overseeing the first field trials of a blue rose developed by Suntory’s subsidiary, Florigene. If the trials are successful, a dozen blue roses – even if they do look slightly mauve – could, by 2010, be available in florists worldwide.
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What Dutch growers of old and Dr Tanaka’s employers both grasped is that rarity, and hence economic value, can be created by genetic manipulation.
The stripes of the Semper Augustus were caused by the genes of a virus. Not knowing that an infection was involved, the Dutch growers were puzzled as to why the Semper Augustus would not breed true. The genetics of blue roses too have turned out to be more complicated than expected. The relevant genes cannot easily be pasted into rose DNA because the metabolic pathway for creating blue pigment in a rose consists of more chemical steps than it does in other types of flower. (Florigene has sold bluish genetically modified carnations since 1998.)
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Success, then, has been a matter of pinning down the genes that allow those extra steps to happen, and then transplanting them to their new host.
Mere colour, however, is for unsophisticated buyers. A truly harmonious gift should smell beautiful as well. Sadly, commercial varieties of cut roses lack fragrance. This is because there is a trade-off between the energy that plants spend on making the complex, volatile chemicals that attract people and insects alike, and that available for making and maintaining pretty coloured petals. So, by artificially selecting big, long-lasting flowers, breeders have all but erased another desirable characteristic.
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Smell is tougher to implant than colour because it not only matters whether a plant can make sweet-smelling chemicals, it also matters what it does with them. This was made plain by the first experiment designed to fix the problem. In 2001, Joost Lucker, then a researcher at Plant Research International in Wageningen, in the Netherlands, added genes for a new scent into small, colourful flowers called petunias. Chemical analysis showed that the new scent was, indeed, being made, but unfortunately the flowers did not smell any different.
As happens in Florigene’s blue carnations and roses, Dr Lucker’s petunias dumped the foreign chemical they were being forced to create into cellular waste buckets known as vacuoles. Whereas pigments are able to alter a petal’s colour even when they are inside a vacuole, because the cell contents surrounding the vacuole are transparent, smelly molecules must find a route to the sniffer’s nose by getting out of the cell and evaporating.
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Like Dr Lucker, Natalia Dudareva, of Purdue University, in Indiana, eschews experiments with roses, since these plants have scents composed of 300 to 400 different molecules. She prefers to understand basic odour science using petunias and other similar plants, which have about ten smelly chemicals apiece. She has made an encouraging discovery. By studying the many different pathways through which flowers make their fragrances, she has found consistent patterns in the way these pathways are regulated.
Such co-ordinated patterns suggest that a type of protein called a transcription factor is involved. Transcription factors switch genes on and off in groups. If Dr Dudareva is right, cut roses have lost their fragrances not because the genes that encode their hundreds of scent molecules have each lost their function, but because the plants no longer make a few transcription factors needed to turn the whole system on.
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This suggests that the task of replacing lost fragrance is more manageable than it seemed at first. But even when the transcription factors in question have been identified, the problem of the energetic trade-off with pigment production and longevity will remain. So Dr Dudareva is also measuring how quickly the enzymes in scent-production pathways work, in order to identify bottlenecks and thus places where her metabolic-engineering efforts would best be concentrated.
Dr Dudareva’s methods may also help to improve the job that flower-scents originally evolved to do attracting insects that will carry pollen from flower to flower. By modifying the smell of crops such as vanilla, which have specific pollinator species, different insects might be attracted. That could expand the range in which such crops could be grown and thus make some poor farmers richer.
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Questions 27-32
Do the following statements agree with the claims of the writer in Reading Passage 3?
In boxes 27-32 on your answer sheet write
YES if the statement agrees with the claims of the writer
NO if the statement contradicts the claims of the writer
NOT GIVEN if it is impossible to say what the writer thinks about this
27. Historically, people have been willing to pay excessive amounts for flowers.
28. Farmers who grow flowers are generally richer than other farmers.
29. Blue roses were available for purchase in the 19th century.
30. Dutch plant growers deliberately used a virus to produce the striped Semper Augustus.
31. Blue carnations are more popular than carnations of other colours.
32. Plant breeders are to blame for the loss of smell in today’s roses.
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Questions 33-36
Choose the correct letter, A, B, C or D.
33. Dr Tanaka hopes that his field trials will
A. result in a more expensive flower than the Semper Augustus.
B. produce blue roses that can be sold commercially.
C. show that flowers can be dyed unusual colours.
D. verify the link between flowers and romance.
34. Dr Lucker’s experiment with petunias showed that
A. plant fragrances depend on the colour of the petals.
B. the more colourful plants are, the less they smell.
C. plants are able to reject the chemicals that produce smell.
D. colour and smell are equally difficult to introduce into plants.
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35. Dr Dudareva prefers to study petunias, rather than roses, because petunias
A. are easier to grow.
B. have a wider range of scents.
C. are found in a wider range of places.
D. have less complex molecular scent structures.
36. In what way could Dr Dudareva’s work benefit agriculture?
A. More farmers would be able to grow flowers.
B. A wider range of insects would pollinate certain plants.
C. More unusual flowers could be created.
D. A wider variety of plant species would be grown.
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Questions 37-40
Choose NO MORE THAN THREE WORDS AND/OR A NUMBER from the passage for each answer.
37. What items were traded for flower bulbs in 17th-century Holland?
38. What aspect of a rose’s internal biology slows down attempts to change its DNA?
39. What is the name of the waste area in which Dr Lucker’s petunias were placing foreign chemicals?
40. What is the name of the protein that plants must make in order to release scent molecules?
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IELTS Academic Reading Test
ANSWERS
27. YES
28. NOT GIVEN
29. NO
30. NO
31. NOT GIVEN
32. YES
33. B
34. C
35. D
36. B
37. HOUSES
38. (ITS/THE) METABOLIC PATHWAY
39. (A/THE) VACUOLE / VACUOLES
40. (A) TRANSCRIPTION FACTOR
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