Search results
Results from the WOW.Com Content Network
Diagram of an ovule in gymnosperms and angiosperms Photomicrograph of an ovule of a monocotyledon. In angiosperms the gynoecium, also called pistil, consists of one or more carpels or carpel leaves that form a cavity, the ovary, inside which the ovules or seminal primordia are protected from both desiccation and attack by phytophagous insects.
In angiosperms, the sporangia are located in the stamen anthers (microsporangia) and ovules (megasporangia). The specialised sporangia bearing stem is the flower . In angiosperms, if the female sporangium is fertilised , it becomes the fruit , a mechanism for dispersing the seeds produced from the embryo.
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.
A fruit is the mature, ripened ovary of a flower following double fertilization in an angiosperm.Because gymnosperms do not have an ovary but reproduce through fertilization of unprotected ovules, they produce naked seeds that do not have a surrounding fruit, this meaning that juniper and yew "berries" are not fruits, but modified cones.
The ovary (from Latin ovum, meaning egg) is the enlarged basal portion which contains placentas, ridges of tissue bearing one or more ovules (integumented megasporangia). The placentas and/or ovule(s) may be born on the gynoecial appendages or less frequently on the floral apex.
The term angiosperm fundamentally changed in meaning in 1827 with Robert Brown, when angiosperm came to mean a seed plant with enclosed ovules. [35] [36] In 1851, with Wilhelm Hofmeister's work on embryo-sacs, Angiosperm came to have its modern meaning of all the flowering plants including Dicotyledons and Monocotyledons.
In most plants, the synascidiate (i.e. "united bottle-shaped") and symplicate zones are fertile and bear the ovules. [9] Each of the first three families possess mainly bi- or multilocular ovaries in a gynoecium with a long synascidiate, but very short symplicate zone, where the ovules are inserted at their transition, the so-called cross-zone ...
Plant ovules: Gymnosperm ovule on left, angiosperm ovule (inside ovary) on right. After fertilization, the ovules develop into the seeds. The ovule consists of a number of components: The funicle (funiculus, funiculi) or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, at the pericarp.