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Dichogamy: Pollen and stigma of the flower mature at different times to avoid self-pollination. Self-incompatibility: In same plants, the mature pollen fall on the receptive stigma of the same flower but fail to bring about self-pollination. Male sterility: The pollen grains of some plants are not functional. Such plants set seeds only after ...
Close-up of a Schlumbergera flower, showing part of the gynoecium (specifically the stigma and part of the style) and the stamens that surround it. Plant reproductive morphology is the study of the physical form and structure (the morphology) of those parts of plants directly or indirectly concerned with sexual reproduction.
Gynoecium (/ ɡ aɪ ˈ n iː s i. ə m, dʒ ɪ ˈ n iː ʃ i. ə m /; from Ancient Greek γυνή (gunḗ) 'woman, female' and οἶκος (oîkos) 'house'; pl.: gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds.
The stigma, together with the style and ovary (typically called the stigma-style-ovary system) comprises the pistil, which is part of the gynoecium or female reproductive organ of a plant. The stigma itself forms the distal portion of the style, or stylodia, and is composed of stigmatic papillae , the cells of which are receptive to pollen.
The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. [11] Only compatible pollen grains are allowed to grow as determined by signaling with the stigma. In the pollen grain, the generative cell gives rise to the sperm, whereas the vegetative cells have a tube cell that grows the pollen tube.
In plants with SI, when a pollen grain produced in a plant reaches a stigma of the same plant or another plant with a matching allele or genotype, the process of pollen germination, pollen-tube growth, ovule fertilization, or embryo development is inhibited, and consequently no seeds are produced.
One of the two pollinia bends itself towards the stigma. Self-pollination is a form of pollination in which pollen arrives at the stigma of a flower (in flowering plants) or at the ovule (in gymnosperms) of the same plant. The term cross-pollination is used for the opposite case, where pollen from one plant moves to a different plant.
[3] [4] Furthermore, the cotyledons in dicot seeds contain the endosperm which acts as the seed’s food storage, while in monocot the endosperm is separated from the cotyledon. [1] Reproduction through seeds is normally a sexual mode of reproduction, however in some cases individuals can asexually produce fertile seeds without pollination ...