建议用时:15分钟
A
[2015·黑龙江大庆质检二]We tend to think of plants as the furniture of the natural world. They don't move, they don't make sounds and they don't seem to respond to anything-at least not very quickly. But as is often the case, our human view of the world misses quite a lot. Plants talk to each other all the time. And the language is chemical.
Over the years, scientists have reported that different types of plants, from trees to tomatoes, release compounds (化合物) into the air to help neighboring plants. These chemical warnings all have the same purpose-to spread information about one plant's disease or infestation so other plants can defend themselves. But exactly how plants receive and act on many of these signals is still mysterious.
In this week's Proceedings of the National Academy of Sciences, researchers in Japan offered some explanations. They had identified one chemical message and traced it all the way from release to action.
The scientists looked at tomato plants infested by a common pest, the cutworm. The researchers studied leaves from exposed and unexposed plants. They found one compound showed up more often in the exposed plants. The substance is called HexVic. When the scientists fed HexVic to cutworms, it knocked down their survival rate by 17%. The scientists identified the source of HexVic, and sprayed it lightly over healthy plants. Those plants were then able to start producing the cutwormkilling HexVic. Researchers confirmed that uninfested plants have to build their own weapons to fight off bugs and disease. How do they know when to play defense? They are warned first by their friendly plant neighbors.
【【金版教程】2017高考英语二轮复习训练:1-1-2 推理判断类a(含解析)】相关文章:
★ 2017高考四川省广安市英语阅读理解一轮系列训练:4(含解析)
★ 湖南省岳阳市2014高考英语一轮单项选择训练题(2)及答案
★ 【优化方案】2017届高考英语二轮复习全国卷Ⅱ规范练:4(含解析)
★ 【优化方案】2017届高考英语二轮复习全国卷Ⅱ规范练:6(含解析)
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (41)
★ 【人教版】2014届高考英语一轮复习指导考点针对练:必修2 unit2《The Olympic Games》
★ 2017届高考英语二轮复习书面表达限时测验:6(含解析)
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (37)
★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (74)
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21