14 Plant Behavior-Mid

Plant Behavior FOCUS Question How do plants respond to the world around them?

植物行为焦点问题植物如何对周围的世界做出反应?

The Life of a Plant You might think being a plant would be boring. You sprout out of the soil. Then you stay in one place your whole life. But there's much more to being a plant than just sprouting and standing still! Plants grow on every continent. They can live where it is hot or cold, wet or dry. To live in so many different places, plants must adapt to their habitat. Plants have parts that help them get water, air, and sunlight. These are physical adaptations. But plants also have behavioral adaptations. That's right. Plants behave, or act, in certain ways! They respond to light, heat, water, and touch.

植物的生活你可能会认为做一棵植物会很无聊。 你从土壤里发芽了。 然后你一辈子都待在一个地方。 但作为一株植物，不仅仅是发芽和静止!植物生长在每一个大陆上。 他们可以生活在炎热或寒冷，潮湿或干燥的地方。 要在这么多不同的地方生存，植物必须适应它们的栖息地。 植物有帮助它们获得水、空气和阳光的部分。 这些都是生理适应。 但是植物也有行为适应。 这是正确的。植物有特定的行为方式!它们对光、热、水和触摸有反应。

Seeking Sunlight All plants need sunlight to stay alive. They use it to make their own food. But getting sunshine isn't always easy. In many forests, large trees create a canopy, or upper layer of leaves. This layer blocks light from reaching the plants below. As a result, those plants actively search for sunlight. Lianas (lee-AH-nuz) are vines found in tropical rainforests. They start life on the ground as small shrubs. But they soon begin to climb toward sunlight. A liana uses sticky hairs to attach to a tree. It also has special stems that grasp the tree as the vine grows. Over time, the vine winds all the way to the top.

所有的植物都需要阳光来维持生命。 他们用它来做自己的食物。 但获得阳光并不总是那么容易。 在许多森林中，大树会形成树冠，即上层树叶。 这一层阻挡了光线到达下面的植物。 因此，这些植物积极地寻找阳光。 藤本植物(lee-AH-nuz)是在热带雨林中发现的藤蔓植物。 它们一开始是在地面上生长的小灌木。 但它们很快就开始向阳光的方向爬去。 藤蔓用粘毛附着在树上。 它还有特殊的茎，可以在藤蔓生长时抓住树。 随着时间的推移，藤蔓一直缠绕到顶部。

Handling Heat Desert plants don't have to worry about finding sunlight. Instead, they must deal with extreme heat and dryness. For example, the leaves of the jojoba (huh-HO-buh) grow straight up and down. At midday, the Sun's rays shine straight down. The rays hit just the edges of the leaves, so the plant stays cooler But when the Sun is rising or setting, the weaker light hits the sides of the leaves. The plant needs this sunlight to make food. To conserve water on a hot day, cacti close their stomata. These tiny holes on the plant take in carbon dioxide. They also give off oxygen and water vapor. Cactus plants wait until the cooler nighttime to open their stomata As a result, they lose less moisture.

沙漠植物不需要担心找到阳光。 相反，他们必须应对极端的高温和干燥。 例如，荷荷巴的叶子(huh-HO-buh)向上向下生长。 正午时分，太阳光线直射。 光线只照射到叶子的边缘，所以植物保持凉爽。但当太阳升起或落下时，较弱的光线照射到叶子的侧面。 植物需要这种阳光来制造食物。 为了在大热天保存水分，仙人掌会关闭气孔。 植物上的这些小孔吸收二氧化碳。 它们还会释放氧气和水蒸气。 仙人掌植物等到凉爽的夜晚才打开气孔，因此，它们流失的水分较少。

Spreading Pollen Arctic poppies live where it is very cold. These bright yellow flowers follow the warm sunlight throughout the day. The sunlight warms the centers of the flowers. This warmth attracts insects that pollinate (PAH-li-nate) the plant. This means they help the plant reproduce. The night-blooming cereus (SEER-ee-us) is a desert cactus. For most of the year, this plant looks like a dead bush. But for only a night or two in the summer, its large flowers open up. That's because the creatures that pollinate it are active at night. Sphinx moths and nectar-feeding bats help pollinate the flowers.

北极罂粟生长在非常寒冷的地方。 这些明亮的黄色花朵一整天都跟随温暖的阳光。 阳光温暖着花心。 这种温暖吸引了授粉的昆虫(PAH-li-nate)。 这意味着它们帮助植物繁殖。 夜花蜡样植物(SEER-ee-us)是一种沙漠仙人掌。 在一年的大部分时间里，这种植物看起来像一株枯死的灌木。 但只有在夏天的一两个晚上，它的大花朵才会开放。 这是因为授粉的生物在晚上很活跃。 斯芬克斯飞蛾和采蜜蝙蝠帮助花授粉。

Waiting for Water Ephemerals (uh-FEM-er-uhls) are plants with short life cycles. They go from seeds to mature plants to new seeds in a very short time. The desert paintbrush is an ephemeral. This plant depends upon rare desert rains. Its seeds wait in the ground until there is enough water. They may sit in the soil for years. When it finally rains, the seeds sense the moisture and sprout. The young plants leap to life, growing quickly. The plants must flower and produce new seeds before the water runs out. The wind scatters the seeds across the desert floor. These new seeds will wait there until it is time to grow again.

蜉蝣是指生命周期短的植物。 它们在很短的时间内从种子到成熟植物再到新种子。 沙漠的画笔是短暂的。 这种植物依赖稀少的沙漠雨水。 它的种子在地下等待，直到有足够的水。 它们可能会在土壤里呆上好几年。 当终于下雨时，种子就会感受到水分并发芽。 幼苗生机勃勃，生长迅速。 植物必须在水分耗尽之前开花并产生新的种子。 风把种子吹散在沙漠地面上。 这些新的种子将在那里等待，直到再次生长的时候。