13 September 2013

CBSE Science notes on plants for Class 6

Parts of a plant

Root system and shoot system are the two main systems in a plant. The root system which contains roots and root hairs remains under the soil in most of the plants. While the shoot system remains erect (upright) above the soil and it has stem, leaves, flowers and fruits.



Roots
  1. The part of the plant that remains under the soil in most of the plants is called the root. These help in fixing the plant firmly into the soil so that the plant does not fall and thus help the plant in standing erect (upright) above the soil.
  2. Roots absorb water and the dissolved minerals from the soil which are used by the plant in the process of photosynthesis for preparing its food.
  3. Roots also store the extra food within them which is used when required by the plant.
Stem
  1. The part of the plant that remains erect (upright) above the soil is called the stem. 
  2. Stem supports all the other parts of the plant.
  3. These help in conducting (taking) water and dissolved minerals from the roots to leaves where the food is prepared. So also stems conduct the prepared food in the form of glucose (simple sugars) from the leaves to other parts of the plant.
  4. In addition to the above functions, in some plants like potato the stem stores food as well which is taken as a vegetable by us.
Leaves
  1. These are the most important part of the plant and are green in color in most of the plants. The green color is due to the presence of the green coloring pigment called chlorophyll present in them.
  2. The chlorophyll is capable of capturing light energy from the sun and convert it into chemical energy in the form of food.
  3. In most of the plants, food in the form of simple sugar (carbohydrate) is prepared in the leaves through a process called photosynthesis.
Flowers
  1. Flower is the most colorful and attractive part of the plant.
  2. These are the reproductive part of the plant. The male reproductive part of the flower is the pollen grain (pollen) and the female reproductive part is the ovary which contains ovules.
  3. After pollination and fertilization of the ovary develops into a fruit while the ovules develop into seeds. These seeds grow into new plants under favorable conditions.
Fruits:
  1. The fleshy edible (eatable) part of the plant which has seeds within it is called the fruit.
  2. Fruits store the food prepared by the plants. 
  3. Seeds are embedded within the fruits and develop into new plants.

Classification of plants

Based on the height of the plant, texture of the stem and certain other characteristics all the plants are mainly divided into three categories viz. herbs, shrubs and trees