TOEFLリスニング

🎧 リスニング原文

Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about a fascinating adaptation in desert plants, specifically the saguaro cactus. The saguaro, native to the Sonoran Desert, can live over 150 years and grow to be 40 feet tall. But what really interests scientists is its root system. Unlike many plants that spread roots deep into the soil, the saguaro has a shallow, widespread root system that extends horizontally, often as far as the plant is tall. These roots are only a few inches below the surface, which allows them to quickly absorb moisture from infrequent rains. The roots also have a special relationship with certain fungi, which help the cactus absorb nutrients more efficiently. Additionally, the saguaro's stem has accordion-like folds that expand to store water after a rain, enabling it to survive long dry periods. This combination of shallow roots and water storage is a remarkable example of adaptation to extreme conditions.