Plastids are membrane-bound organelles found in plant cells. There are three main types of plastids: chloroplasts, which contain chlorophyll and are the site of photosynthesis; chromoplasts, which contain carotenoid pigments and impart color to parts of plants; and leucoplasts, which are non-pigmented and found in non-photosynthetic tissues like roots and seeds.

1. PLASTIDS
INTRODUCTION
Plastid is a two-layered membrane-bound organelle found
in the cells of plants that are involved in the
photosynthesis and storage of food.Ernst Haeckel coined
the term plastid in the year 1886,but A.W.F Schimper who
gave the proper defination about plastids.there are three
types of plastids :- Chloroplasts,Chromoplast,Leucoplast.

2. CHLOROPLAST
A chloroplast is an organelle within
the cells of plants and certain algae
that is the site of photosynthesis,
which is the process by which
energy from the Sun is converted
into chemical energy for growth.
chloroplast contains chlorophyll to
absorb light energy.

3. CHROMOPLAST
Chromoplasts are colored plastids
that contain carotenoid pigment.
They are ellipsoid, round, or
needle-shaped structures. The
function of chromoplasts
is imparting color to certain parts
of plants such as flower petals,
fruits, some roots, etc. so that
insects are attracted for
pollination.

4. LEUCOPLAST
Leucoplasts are a category of
plastid and as such are organelles
found in plant cells. They are non-
pigmented, in contrast to other
plastids such as the chloroplast.
Lacking photosynthetic pigments,
leucoplasts are not green and are
located in non-photosynthetic
tissues of plants, such as roots,
bulbs and seeds.