D
跨学科 生物(2025·深圳期中)
Young corn leaves can “smell” danger, but they lose this ability as they grow older, according to new research by Lei Wang and his team at the University of Bern.
Plants can sense danger through smells, even though they don’t have noses. They can smell insect saliva (唾液). For example, when an insect eats corn leaves, the plant can smell the insect’s saliva and prepare to protect itself. Scientists have known this for a long time, but they didn’t know which parts of plants can sense danger or how they do it.
Wang’s team first studied adult corn leaves but found they didn’t produce many defense chemicals (防御化学物质) when in danger. So they had to turn over a new leaf. They studied young leaves instead, because young leaves were better at “smelling” danger. In lab tests, young leaves produce more defense chemicals than adult leaves. However, adult leaves can still notice other dangers, like insects eating them.
The researchers think young leaves are better at sensing danger because they are weaker and at the top of the plant. From there, they can smell things from far away. This helps the plant get an early warning.
Wang hopes this research will help develop smarter crops that can fight insects, cutting down the need for harmful pesticides (杀虫剂). By doing this research, he wants to help solve big farming problems.
()27. What does the underlined phrase “turn over a new leaf” in the passage mean?
A. Improve a leaf’s health.
B. Study a different leaf.
C. Grow a fresh new leaf.
D. Change the smell of a leaf.
()28. Why are young leaves better at sensing danger?
A. They get hurt more easily.
B. They can kill insects quickly.
C. They are stronger than adults.
D. They grow faster than adult leaves.
()29. What will Lei Wang probably do in his future work?
A. He will test leaf chemicals.
B. He will create stronger pesticides.
C. He will grow crops against insects.
D. He will study old leaves’ problems.
()30. Which is the best title for the passage?
A. The Secret Life of Plants
B. Young Corn Leaves’ Special Ability
C. A Study on Corn and Insects
D. Farmers’ Fight Against Plant Insects

【语篇解读】本文是一篇说明文。文章主要介绍了王雷团队关于“玉米幼苗叶片具有危险感知能力、成年叶片丧失该能力”的研究发现、背后原因，以及该研究对农业领域的应用价值。
27. B 词义猜测题。根据“Wang's team first studied adult corn leaves but found they didn't produce many defense chemicals when in danger. So they had to turn over a new leaf. They studied young leaves instead”可知，研究团队开始研究另一种年轻的叶子，而非改变叶子的味道或生长状态。故选 B。
28. A 细节理解题。根据“The researchers think young leaves are better at sensing danger because they are weaker and at the top of the plant. From there, they can smell things from far away. This helps the plant get an early warning.”可知，年轻的叶子更容易受到伤害，因此更擅长感知危险。故选 A。
29. C 推理判断题。根据“Wang hopes this research will help develop smarter crops that can fight insects, cutting down the need for harmful pesticides. By doing this research, he wants to help solve big farming problems.”可知，该研究有助于培育“更聪明”的作物以减少杀虫剂的使用，说明 Lei Wang 的研究目标是培育能抵御昆虫的作物。故选 C。
30. B 标题归纳题。通读全文可知，文章核心在介绍年轻玉米叶子特殊的“嗅”危险能力，最能概括全文的标题为选项 B“年轻玉米叶子的特殊本领”。故选 B。