What are plants?

1. Plants are one of the two groups into which all living things were traditionally divided; the other is animals. The division goes back at least as far as Aristotle (384 BC – 322 BC) who distinguished between plants which generally do not move, but their leaves move to catch the sun and their roots move towards water. Plants have cell structure with walls containing cellulose, and organisms capable of photosynthesis. Plants need air, water, soil, and sunlight to live and manufacture their own food. They include familiar organisms: trees, forbs (разнотра́вье), shrubs, grasses, vines, ferns, and mosses. To see a presentation follow www.slideshare.net

2. Some plants in the pea family have a rather unusual ability that sets them apart from the rest of the plant world. They can collapse their leaves and stems when touched or disturbed in some way. The best known of these ‘sensitive plants’ is Mimosa pudica, a tropical weed (сорняк) that comes from South and Central America.

3. It is a complex process that happens within the plant’s cells that provide support to the leaves and stems. The cells are filled with water, which keeps them turgid and firm, when the plant is touched the cells release the water deflating them, resulting in the leaves and stems to collapse (сжиматься) and fold inwards… if you watch closely, a few minutes later the water will be pumped back and they will return to normal.

4. So why do they do it? Plants have to come up with many clever ways to stop themselves being munched on by animals and insects, as they can’t run away and hide! So the drooping leaves will deter (удерживать) hungry animals and hopefully shake off insects. The sensitive plant also comes in quite useful if you get bitten by a monocled Cobra snake, the extracts from the roots can be used to counteract the venom (яд).