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Location of ovules inside a Helleborus foetidus flower. In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the integument, forming its outer layer, the nucellus (or remnant of the megasporangium), and the female gametophyte (formed from a haploid megaspore) in its center.
Micropyle may refer to: Micropyle (botany) a minute opening in the integument of an ovule of a seed plant. Micropyle (zoology) , a differentiated area of surface in an egg, through which a sperm enters
Endocardial cushions, or atrioventricular cushions, refer to a subset of cells in the development of the heart that play a vital role in the proper formation of the heart septa. They develop on the atrioventricular canal [2] and conotruncal region of the bulbus cordis. [3] During heart development, the heart starts out as a tube. As heart ...
(of an ovule) Bent so that both ends are near each other. Contrast anatropous, campylotropous, and orthotropous. amplexicaul With the base dilated and clasping the stem, usually of leaves. amylum star a vegetative propagative body filled with starch (amylum) and located around the lower nodes of certain stonewort s. anastomose
The micropyle, a small pore or opening in the apex of the integument of the ovule where the pollen tube usually enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, where integument and nucellus are joined. [8] The shape of the ovules as they develop often affects the final shape of the seeds.
Placental areas occur in various positions, corresponding to various parts of the carpels that make up the ovary. See Ovule#Location within the plant. An obturator is present in the ovary of some plants, near the micropyle of each ovule. It is an outgrowth of the placenta, important in nourishing and guiding pollen tubes to the micropyle. [17]
In flowering plants, the ovule (from Latin ovulum meaning small egg) is a complex structure born inside ovaries. The ovule initially consists of a stalked, integumented megasporangium (also called the nucellus). Typically, one cell in the megasporangium undergoes meiosis resulting in one to four megaspores. These develop into a megagametophyte ...
This develops within an ovule, enclosed by the ovary at the base of a carpel. Surrounding the megagametophyte are (one or) two integuments, which form an opening called the micropyle. The megagametophyte, which is usually haploid, originates from the (usually diploid) megaspore mother cell, also called the megasporocyte. The next sequence of ...