$\Rightarrow$   Plastids are found in all plant cells and in euglenoides.

$\Rightarrow$ These are easily observed under the microscope as they are large.They bear some specific pigments, thus imparting specific colours to the plants.

$\Rightarrow$ Based on the type of pigments plastids can be classified into three types

$(a)$ Chloroplasts $(b) $ Chromoplasts and $(c)$ Leucoplasts.

$(a)$  Chloroplasts : The chloroplasts contain chlorophyll and carotenoid pigments which are responsible for trapping light energy essential for photosynthesis.

$(b) $ Chromoplasts : In the chromoplasts fat soluble carotenoid pigments like carotene, xanthophylls and others are present. This gives the part of the plant a yellow, orange or red colour.

$(c) $ Leucoplasts : The leucoplasts are the colourless plastids of varied shapes and sizes with stored nutrients.

$(i)$ Amyloplasts : Store carbohydrates e.g., potato

$(ii) $ Elaioplasts : Store oils and fats

$(iii) $ Aleuroplasts : Store proteins.