What are plastids
And what is a middle lamela ​

Plastids are an organelle  type found in all plants and algae, never in animals, fungi, or prokaryotes . It contains inner and outer membrane , stroma filled with fluid , and it has many, many functions.

Middle Lamella is the outermost layer of the cell. It acts as an adhesive, sticking adjacent plant cells together and gives the plant stability, channels in the cell walls that link adjacent cells together, and allow transport of substances and communication between cells.

Explanation:

The middle lamella is a layer which cements the primary cell walls of two adjoining plant cells together. ... In a mature plant cell it is the outermost layer of cell wall. In plants, the pectins form a unified and continuous layer between adjacent cells.

Plastids are defined as small organelles present in the cytoplasm of the plant cell. ... Chloroplasts - These kind of plastics are used in the process of photosynthesis as they have green colored pigment.