Chloroplast is the site of photosynthesis. It is one of a number of plastide,all of which develop from proplastids which are small, pale green or colourless organelles.
Other typical plastids of complex cells are chromoplasts which may develop from chloroplasts by internal rearrangements. Chromoplasts are coloured due to the presence of carotenoid pigments and most abundant in cells of flower petals or fruit skins.
Leucoplasts are a third type of plastid common in cells of higher plants -they include amyloplasts which systhesize and store starches and elaioplasts which synthesize oils.