Embryo sacs of some apomictic species appear normal but contain diploid cells. Suggest a suitable explanation for the condition.
The condition in which seeds are produced without fertilization is called apomixis. It is a kind of asexual reproduction, but it mimics sexual reproduction. There are several mechanisms for apomixis. One of them is seen in citrus and mango fruits. In this case, the nucellus beings to divide and intrude into the embryo sac. It eventually develops into a seed. Since nucellus is composed of diploid cells, the embryo sac in such a case has diploid cells.
It is also important to recall that fertilization cannot happen in the cells which were not formed after meiosis. Moreover, haploid cells are never involved in apomixis. It is the diploid cells which bring about apomixis. Hence, embryo sacs apomictic species appear normal but contain diploid cells.