TEXT 5. THE TYPICAL SEED PLANT

The common garden bean is a typical seed plant. The vegetable called "bean" is the seed of the bean plant and is contained in a pod. This pod, with its seeds, is the fruit of the plant. The bean seed has two seedleaves, or cotyledons¹, that surround a baby bean plant, or embryo. The cotyledons supply the embryo with food and act as a protective covering. If the seed is planted properly in soil and is watered, it will germinate, meaning a young bean plant will emerge from the seed planted. This plant has roots, stems, and green leaves that have chlorophyll, enabling it to manufacture its own food.

The young plant grows rapidly, producing additional roots, stems, leaves, and finally blossoms. When the flowers appear the plant is ready to reproduce (produce offspring). Each bean flower has tiny yellowish pollen grains, which are transferred to its own female structure or that of another bean plant's flower. The pollen contains sperms, or male cells, that bring about fertilization of the eggs, or female cells, which are in the ovary of the female structure. The fertilized egg develops into an embryo, while the rest of the egg becomes its seed. The ovary wall enlarges to become a pod, which is the fruit of the bean plant, and the whole life process begins again. A similar process takes place in the pine, spruce, apple, peach, oak, grass, and all other seed plants.

The major parts of a seed plant are roots, stems, leaves, flowers, seeds, and fruit. Each of these structures plays an important part in the life of the plant. Some seed plants are annual², that is they complete their life cycle from seed to seed in one year; such plants include the bean, pea, and the grasses. Others are biennial³, needing two years for the cycle to be completed, these include the beet, parsnip, and carrot. Many are perennial, living for many years; among these are the oak, pine, rose, and lilac. Although there are many variations in different species of seed plant, their principle structures are basically alike and perform the same functions. The roots anchor the plant in the soil and support it. They absorb water and mineral salts from the soil and pass them along to the conducting tubes in the stem to be carried to the leaves. Many roots also store food.

The leaves carry on the process of photosynthesis and are equipped to give off excess water in the form of water vapour. The roots, stems and leaves all are equipped to take in oxygen, which the plant uses to carry on all activities except photosynthesis.

The seed is the structure whereby seed plants can survive over long periods of time under unfavourable conditions. Many kinds of seeds can retain their ability to germinate for many years after they are formed, and need only moisture, warmth and soil to develop into a new plant.

Questions

1) What is a typical seed plant?

2) What does the bean plant consist of?

3) What part do the cotyledons play in the life of the bean plant?

4) What plants are called annual?

5) What plants are called biennial?

6) What are perennial plants?

7) What are the main functions of the roots?

8) What are the functions of the leaves?

Notes

1. cotyledon - семядоля

2. annual - однолетние

3. biennial - двухлетние