Maximum DNA synthesis during the midproliferative phase of the cycle (i.e. cycle days 8â10) correlates with the maximum number of mitoses in both the stromal and epithelial endometrial cellular elements, as well as with the midproliferative peak of plasma estradiol and nuclear estradiol receptors.
Some defining characteristics of angiosperms include flowers, carpels, and the presence of endosperm, a nutritive substance found in seeds, produced via a second fertilization event. However, some current studies suggest that endosperm is not unique to angiosperms.
Double fertilization. The pollen tube enters the ovule through the micropyle and ruptures. double fertilization A character istic of angiosperm s in which a pollen tube carries two sperm cells to the female gametophyte in the ovule. double fertilization.A mechanism of fertilization in angiosperm s, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm. double helix ... Double fertilization gives rise to the zygote and endosperm.After landing on a receptive stigma, the pollen grain absorbs moisture and germinates, producing a pollen tube that extends down the style toward the ovary. mechanism of fertilization in angiosperm s, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm. double helix ... Double fertilization gives rise to the zygote and endosperm.