. Plastids are species specific and are found in all plant cells and in euglenoids. They bear some specific pigments thus, imparting specific colours to the part of the plant which
possess them. Based on the type of pigmentsplastids are classified into three main types,
i.e., leucoplasts, chromoplasts and chloroplast
Leucoplasts They are colourless plastids whichstore food material based on there storage products
 theyare of three types
(a) Amyloplasts Stores starch, e.g., tuber of potato, grain of rice, grain of wheat.
(b) Elaioplasts Thesestore fats, e.g., rose
(c) Aleuroplasts Theyare protein storing plastids, e.g., castor endosperm
Chromoplast These are non photosynthetic coloured plastids which synthesise and store carotenoid pigments. They appear orange, red or yellow. These mostly occur in ripe fruits
(tomato and chilles) carrot roots, etc.
Chloroplasts These are green colour plastids which help in synthesising food material by photosynthesis. They contain chorophyll and carotenoid pigments which trap light energy.
Eachchloroplast is oval or spherical, double membrane bound cell organelle.
The space presentinside inner membraneis called stroma.A number of organised flattened membranous sacs called thylakoids are presentin the stroma. Thylakoids are arranged in
stacks are called grana.
The thylakoids ofdifferent grana are connected by membranous tubules called the stroma lamellae. The stroma of the lameliae contain the enzymes that are required for the synthesis
of carbohydrates