"Natural Science 4" is an interactive encyclopedia that includes scientific information in the understanding of fourth grade students, wonderfully illustrated and animated.
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www. edituraedu.ro
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* Chapter 1 Lesson 2 *
* Plant life cycle *
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Like humans and animals, plants are living organisms. They are spread all over the earth, having different shapes, colors and sizes. But no matter how different they are, they all need air, water, light and the right temperature to live and thrive.
Plants cover most of our planet. Every blade of grass, flower, tree, fern, moss or shrub is a plant. On the ground or in the water, in the forest or in the desert, in the field or among the rocky peaks of the mountains, plants are found everywhere.
In most cases, the life of a plant begins with the seed. Surely, you have seen different types of seeds, and even eaten some of them. There are many kinds of seeds, such as sunflower, pumpkin or apple seeds, wheat and corn kernels, peas and beans, tiny poppy seeds and chia seeds - all of them hide a new life inside.
In nature, seeds roam in search of a suitable place to germinate in a variety of ways. Some are blown by the wind, others float on water or are carried by birds, insects or other animals. Of course, people plant seeds to propagate the plants they want.
But what is the path that the seed takes until it becomes a new plant?
To answer this question I suggest you split open a bean. Inside it you will notice a miniature, undeveloped plant. This is an embryo or future plant. When the seed encounters favorable living conditions, such as fertile soil, water and the right temperature, it germinates or sprouts. In contact with water, the protective covering of the seed softens, cracks and thus the embryo begins to develop. The downward-facing root grows first, then the upward-facing stem toward the light, after which the first two leaves, called cotyledons, appear.
At this stage we have a seedling. The plant grows, develops until its flowers appear. With the help of the wind or insects, the flowers are pollinated and turn into fruits containing seeds. Thus, it reaches the stage of an adult plant that produces seeds.
The stages a plant goes through , from the seed stage to the adult plant stage, capable of producing new seeds, form its life cycle.
The length of the life cycle in plants is different. Some plants have a cycle of one year (annual plants, such as corn, wheat, peas), others of 2 years (biennial plants, for example, onions, cabbage, beets) or of several years (perennial plants - trees and shrubs).
At the end of the cycle, annual or biennial plants die. Perennial plants, once mature, resume the flowering cycle.
But do all plants reproduce by seeds? Find information on how to propagate fern and moss.