Why is it a wonderful leaf?

There are thousands of plants in the world, so the leaves of plants have various shapes. These different shapes of plant leaves have many wonderful things.

Let's talk about Simao first. There are many sharp teeth on its leaf edge. This is for self-defense. Luban, who was cut by his "self-defense resistance", was inspired to create the world's first saw.

Coconut trees growing by the sea have very wide leaves, so why are they safe in the heavy wind and rain? It turns out that its leaf surface has bumps or depressions. It is these ripples that enable the leaves to bear more pressure. It's like a piece of plain paper can't bear anything, but if you fold it into a fan, it can bear the pressure of heavy objects.

Plantago is very common, but there is a surprising secret in its leaves: its leaves are arranged in a spiral shape, and the angle between the two leaves is actually137 30', so that all the leaves can be irradiated by the sun. Therefore, people were inspired to build spiral tall buildings, so that the sun can shine on every room.

Corn leaves are cylindrical and have special significance. Facts have proved that it makes the leaves stronger and less likely to be destroyed. People imitate its shape to build bridges across straits or rivers, but it is very strong.

It can be seen that the structure of plant leaves is very ingenious and its significance is far-reaching. Changing fruit

Among flowering plants, many plants can form real fruits. However, due to the different structural characteristics of various plant fruits, the types of fruits are also diverse.

The mesocarp of some plant fruits is fleshy, while the endocarp becomes separated plasma cells. People call these fruits berries, such as grapes, tomatoes and persimmons. Citrus with attractive aroma is the product of the combination of exocarp and mesocarp, and the endocarp is separated into petals in the middle of the fruit, which is called citrus fruit. Everyone is familiar with sunflower, buckwheat and so on. Their skin is dry, thin and sometimes hard. Only by peeling off their skins can they get real seeds. This kind of fruit is called achene. Some fruits have wings and can float far away with the wind. They are called samara, such as the seeds of maple trees. The fruits of plants such as chestnuts and hazelnuts have a very hard shell with only one seed in it. Because it is hard, it is called a nut. Some fruits, such as soybeans, will split automatically when they are ripe. This is called a pod. In addition, there are some special fruits, such as succulent strawberry fruits that people eat. The truly edible part is replaced from the container. There are countless sesame seeds on strawberry fruit, which is the real strawberry fruit. This kind of fruit is called aggregate fruit.

Ginkgo biloba, which is familiar to everyone, is picked from the ginkgo tree. When it was first picked, it was plump with a thick layer of meat. When people eat, they remove the outer layer of meat, leaving only a ginkgo with a hard shell. Although there is meat and shell, it is actually a typical fake fruit. If you carefully observe the growth process of ginkgo biloba, you will find that there are no decent "flowers" on the ginkgo tree, and you can't find a small bottle-shaped ovary. What you see is only a naked ovule, which can keep growing and eventually form ginkgo biloba. It can be seen that Ginkgo biloba is not a fruit, but a seed. Other trees, such as rubber pine, cypress and Chinese fir, can only bear seeds and have no real fruit. People call this plant gymnosperms.

Generally speaking, if there is fruit, there must be seeds. But there are special exceptions, such as bananas, which have no seeds. How can it bear seedless fruit? It turns out that bananas are not fertilized after flowering. Although the ovary has grown up, the ovules in the ovary cannot develop into seeds because they are not fertilized. This phenomenon is called seedless fruiting or parthenocarpy.