The biggest difference between plant tissue culture and natural growth and differentiation of cells is to artificially regulate the growth of plants, but to artificially simulate natural environmental conditions to promote their growth and development, and the conditions for their growth and development are generally indispensable. The morphological structure of cells needs to change during differentiation, so A and B are wrong. Differentiation must be induced and regulated by hormones, so C is wrong; Hormones needed for differentiation in plant tissue culture mainly come from artificially added exogenous hormones, while endogenous hormones in plants play a role in cell differentiation under natural conditions, so D is correct.