英語(yǔ)時(shí)差：綠色植物能預(yù)知未來？2

Gardeners and botanists have known for a long time that when a green plant is shaded by neighboring plants it will often react by elongating its stem. This so-called shade-avoidance reaction raises the plant’s leaves out of the shade, toward the light. Now three scientists at the University of Buenos Aires have found evidence that plants can sense the presence of neighbors that might cast shadows on them at some future time. The scientists transferred seedlings of white mustard into soil already occupied by similar seedlings of the same height. Within three days, the stems of the newly transferred seedlings began growing faster than before, even though the neighboring plants were too far away and still too short to cast shade on them.