The somatic cells of the apple tree have 34 chromosomes. Determine the number of chromosomes in the cells of the leaves and in the nuclei of the cells of the female gametophyte (embryo sac) of the apple tree. Explain from what initial cells and as a result of what division these cells are formed.
1) the cells of the leaves of the apple tree (somatic cells) have a double set of chromosomes – 34, since an adult plant develops from an embryo (zygote) by mitosis; 2) the female gametophyte (embryonic sac) has six haploid cells (of which one is an egg) with a set of chromosomes – 17, and one central diploid cell, in which there are 34 chromosomes; 3) the female gametophyte is formed from the haploid megaspore by three mitotic divisions, as a result of which 8 haploid cells are formed, two of them merge and form the central diploid cell of the embryo sac.
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