Scientists already know that plants are highly sensitive to touch of any kind. If you've ever touched Mimosa pudica （含羞草），you've already witnessed its fan-like leaves close up. But most of the time, the effect is invisible, or immediately invisible. A recent study found that touching plants causes such a dramatic response in their hormones and gene expression that it could greatly prevent their growth.
The team touched thale cress, a weedy plant, with soft paint brushes, and then analyzed the plant's biological responses. "The lightest touch from a human, an animal, an insect, or even plants touching each other in the wind, causes a huge gene response in the plant," Jim Whelan, a biologist at La Trobe University in Australia, said in a statement. "Within 30 minutes of being touched- 10% of the plant's genome （基因组）is changed."
Previous research has suggested that touch could actually be beneficial, because it stimulates （刺J 激）the plant,s immune system. But this study found that the plants used many resources to respond to touch, which are then not available for growing. The researchers found if they touched a plant multiple times, this was enough to reduce its growth rate by as much as 30%. Other papers have similarly shown that touch can change plant growth； a paper released in 2016 found that even a gentle pat could change the expression of thousands of genes within the same plant.
^uWhile plants don't appear to complain when we step on them, or just brush by them while going for a walk, they're fully aware of this contact and rapidly respond to our treatment of them," said Olivier Van Aken, a plant biologist at the University of Western Australia.
Whelan and his team uncovered more information about the genetic pathways that are activated by touching a plant, which may be useful for developing more resilient （能复原的） plants. Whelan told the Sydney Morning Herald that the findings are likely most useful for the agriculture industry： if plant scientists can find ways to change that defensive response, produce yields （产量）could potentially go up.
32. How does touch prevent a plant growing?
A. By causing genetic changes.
B. By conveying harmful substances.
C. By stopping it absorbing nutrients.
D. By damaging its inner structure.
33. What can be concluded from Olivier Van Aken's words about plants?
A. They are easy to look after.
B. They respond rapidly to any contact.
C. They never have feelings for touch.
D. They are allergic to any human activity.
34. What does the last paragraph focus on?
A. The significance of the study.
B. The approaches to the findings.
C. The way to develop resilient plants.
D. The information about increasing produce yields.
35. What can be the best title for the text?
A. Plants, gene expression is defined by touch
B. Touch will help increase produce yields .
C. Something is done to help plants grow
D. Plants don't really like to be touched
32. A 细节题。根据第1段最后一句和第2段最后一句可知，触碰植物会导致它的基因发生变化，从而阻碍植 物的生长。
33. B推断题。根据第4段可知，植物对任何触碰都能快速做出反应。
34. A推断题。根据最后一段可推知.本段重点介绍这项研究的意义。
35. D主旨题。根据全文可知，触碰植物会阻碍它们的生长,它们不喜欢被触碰。