20 Traveling Seeds-Low

TRAVELING SEEDS FOCUS Question How does the structure of seeds help plants survive?

旅行的种子焦点问题种子的结构如何帮助植物生存?

Seeds What do corn kernels, peas, and dandelion puffs all have in common? They are all seeds! A seed is the part of a plant that can grow into a new plant. Each seed has a strong outer shell called the seed coat Inside the seed is a tiny plant, or embryo (EM-bree-oh). The embryo grows into a new plant. The seed also contains food for the tiny plant. This food gives the growing plant energy until it can make its own food. Before they can grow, seeds need to find the perfect place. Seeds can grow only in places with water, air, light, and space. Animals move by using their legs, wings, or flippers. How do seeds find the perfect place to grow? The way a seed moves depends on its size, shape, and the habitat where it grows.

玉米粒、豌豆和蒲公英泡芙有什么共同之处? 他们都是种子!种子是植物的一部分，可以长成新的植物。 每颗种子都有一层坚固的外壳，叫做种皮。种子里面是一株小植物，或称胚(EM-bree-oh)。 胚胎长成一株新植物。 种子也含有这种小植物的食物。 这些食物为生长中的植物提供能量，直到它能自己制造食物。 在种子生长之前，它们需要找到一个完美的地方。 种子只能在有水、有空气、有光、有空间的地方生长。 动物靠腿、翅膀或鳍状肢移动。 种子如何找到完美的生长环境? 种子移动的方式取决于它的大小、形状和生长的栖息地。

Gravity Many seeds move by falling to the ground. Gravity causes them to move. Think about an apple. The fruit gets heavy and falls off the tree. The fruit may roll a little, but it stays close to the tree. Inside the fruit are the seeds. The fruit may rot and release seeds. Softer fruits may break open when they fall. Eventually, the seeds get buried in the soil. There they can sprout into new plants.

许多种子通过落到地面来移动。 重力使它们移动。 想象一个苹果。果实变重了，从树上掉了下来。 果实可能会滚动一点，但它会紧挨着树。 果实里面是种子。 水果可能会腐烂并释放种子。 较软的水果掉落时可能会裂开。 最终，种子被埋在土壤里。 在那里它们可以长成新的植物。

Wind Some seeds move farther away from their parents. This way, new plants do not have to compete with their parents for water, sunlight, and space. The wind can blow seeds far away. Seeds that move by wind have special parts to help them lift up and blow away. For example, dandelion seeds are very small and light, with a puff of fluff on top. This makes it easy for them to fly in the wind. Think About It Why do you think a dandelion produces so many seeds?

有些种子会远离它们的父母。 这样，新的植物就不必和它们的父母争夺水、阳光和空间。 风可以把种子吹到很远的地方。 随风移动的种子有特殊的部分来帮助它们升起和吹走。 例如，蒲公英的种子很小很轻，上面有一层绒毛。 这使得它们很容易在风中飞行。 你认为蒲公英为什么会结出这么多种子?

If you have ever watched an old Western movie, you probably saw tumbleweeds rolling down a dusty street. Tumbleweeds are dried-up plants that still have seeds. As the tumbleweeds roll, seeds break off and land in new places. Tumbleweeds can spread their seeds very far. Maple seeds also move in the wind. These seeds are sometimes called whirlybirds or helicopter seeds. They have thin wings that help them spin and fly in the wind. Math Moment Winged seeds can travel 200 miles. in the wind, while dandelion seeds can travel 500 miles How much farther can the dandelion seeds travel?

如果你看过一部老西部电影，你可能会看到风滚草在尘土飞扬的街道上翻滚。 风滚草是一种有种子的干枯植物。 随着风滚草的滚动，种子脱落并落在新的地方。 风滚草可以把种子传播得很远。 枫种子也会随风移动。 这些种子有时被称为旋翼鸟种子或直升机种子。 它们有薄薄的翅膀，可以帮助它们在风中旋转和飞行。 带翅膀的种子可以飞行200英里。 在风中，蒲公英的种子可以飞500英里蒲公英的种子还能飞多远?

Animals Have you ever seen a bird with a berry or a squirrel with a nut? If so, you know another way that seeds move. Animals carry them. Animals carry seeds to new places. Insects move seeds only short distances, but birds can carry seeds far away. Ants that move seeds use them for food. They eat the seed coat and leave the embryo to grow. Some animals, such as squirrels and birds, bury seeds in the ground to eat later. This keeps them from being eaten by other animals. Most of the seeds do get eaten, but some of the seeds grow into new plants. Wowser! Scientists found 32,000-year-old seeds in an old animal burrow. Amazingly, the scientists were still able to grow the seeds!

你见过鸟吃浆果或松鼠吃坚果吗? 如果是这样，你知道种子移动的另一种方式。 动物携带它们。动物把种子带到新的地方。 昆虫只能短距离地传播种子，但鸟类可以把种子带到很远的地方。 蚂蚁用种子作为食物。 它们吃掉种皮，让胚生长。 有些动物，如松鼠和鸟类，把种子埋在地下，以后再吃。 这可以防止它们被其他动物吃掉。 大多数种子确实被吃掉了，但有些种子会长成新的植物。 老古板!科学家们在一个古老的动物洞穴中发现了3.2万年前的种子。 令人惊讶的是，科学家们仍然能够种植这些种子!