Question

meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuoles

Answer 1

Actually, the main function of the vacuoles in plant cell is for providing support.

Since, Meristematic tissue have to divide, so they don't need any supportive organnelle like vacuole. So, they lacks in vacuole.

Answer 2

because they have the ability to divide and form new cell. but there is no point in storing food and other nutrients when the has to divide