Why do cells of plants roots generally lack chloroplast?

Because chloroplast comes from a green chlorophyll which is a green nutrient that comes from energy from the sun and since the roots are usually in the ground they dont get sun

Chloroplasts contain chlorophyll, which is a green pigment that can change the light energy of the sun into fuel. Plants take carbon dioxide from the air and water from the soil and change them into sugars ... The function of the roots is to absorb and store water and nutrients from the soil and to support the plant.