Is there a species-specific or region-specific type of plastids? How does one distinguish one from the other?
Ans.
Plastids are species-specific and not region-specific and are found in all plants and euglenoids. Different type of plastid consists of different pigment; thus, imparting different colours at the parts where they are found. On the basis of the colour they impart, plastids can be divided into three types:
Leucoplasts: These are colourless plastids that impart no colour to the parts of the plantwhere they are located. A plant with only leucoplasts is pale white in appearance. The primary function of this plastid is to store foods for the plant. There are three types of leucoplasts- Amyloplaststs, elaioplasts, and aleuroplast. Amyloplast helps in storing starch;elaioplast helps in storing fats, and aleuroplast helps in storing proteins.
Chromoplasts: These are not colourless but essentially non-green plastids. They impart colours other than green to plants. Various colours other than green found in petals and fruits are because of chromoplasts.
Chloroplasts: Chloroplasts consist of a green pigment called chlorophyll which imparts the green colour to the plant and also helps in trapping sunlight which is an essential function for photosynthesis.