Listen to part of a lecture in a biology class. Professor: Today we're going to discuss a fascinating adaptation in desert plants: the phenomenon of seed dormancy. In many desert ecosystems, rainfall is unpredictable. Some years there might be plenty, but other years there might be almost none. To survive this variability, certain plants have evolved seeds that remain dormant, sometimes for decades, until specific conditions trigger germination. For example, the seeds of the desert lupine require a period of intense heat, such as a wildfire, to crack their hard outer coat. Other seeds, like those of the creosote bush, need a certain amount of rainfall to wash away chemical inhibitors on the seed surface. This mechanism ensures that germination occurs only when there is enough water for the seedling to survive. Interestingly, this strategy is not foolproof. If seeds germinate after a single light rain, the young plants may not have enough moisture to complete their life cycle. Therefore, some species have evolved a bet-hedging strategy, where only a fraction of seeds germinate in any given year, while the rest remain dormant for future years.
❓ 题目 According to the professor, what is the main reason desert plants have evolved seed dormancy?
A. To protect seeds from being eaten by animals.
B. To ensure germination occurs only when water is sufficient for survival.
C. To allow seeds to spread over a wider area.
D. To speed up the growth process after rainfall.
✅ 正确答案
To ensure germination occurs only when water is sufficient for survival.
