apospory


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Related to apospory: apogamy

ap·o·spor·y

 (ăp′ə-spôr′ē, ə-pŏs′pə-rē)
n.
The development of a gametophyte directly from a sporophyte without the occurrence of meiosis or spore formation.

a·pos′por·ous (ə-pŏs′pər-əs), ap′o·spor′ic (-spôr′ĭk) adj.

apospory

(ˈæpəˌspɔːrɪ)
n
1. (Botany) botany development of the gametophyte from the sporophyte without the formation of spores
2. (Botany) the development of an embryo of a flowering plant outside the embryo sac, from a cell of the nucellus or chalaza
[C19: from apo- + spore + -y1]

ap•o•spor•y

(ˈæp əˌspɔr i, -ˌspoʊr i, əˈpɒs pə ri)

n.
the development of a gametophyte from a sporophyte without meiosis.
[1880–85]
ap`o•spor′ic (-ˈspɔr ɪk, -ˈspɒr-) a•pos′por•ous, adj.
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References in periodicals archive ?
Apogamy and apospory demonstrated that gametophytes could transform into sporophytes, and vice versa, without the intervention of specific cells (eggs or spores).
4%) formed some aposporous embryo sacs in addition to the normal meiotic sac, and the remaining 27 plants were free of apospory.
Apogamy ("without gametes") and apospory ("without spores") are, to an extent, misnomers, because in some instances gametes and spores are still produced in the life cycle when these phenomena occur; the chromosome complement of the apogamously tbrmed sporophyte and aposporously produced gametophyte is, however, sometimes other than the usual for these generations (for example, both gametophyte and sporophyte in the life cycle may be found to be diploid).
The grass reproduces primarily by apomixis with the mechanism being apospory followed by pseudogamy (Fisher et al.
asexual reproduction by seeds) is a common trait in the genus, being apospory (in which a non reduced megagametophyte originates from a somatic cell, usually a nucellar cell) the most frequent type, and diplospory (in which a non reduced megaspore originates from the reproductive cell itself, with the later failing to successfully complete meiosis) only of occasional occurrence (Quarin, 1992).
The grass reproduces primarily by apomixis, with the mechanism being apospory followed by pseudogamy (Fisher et al.
squamulatum, (ii) compare anomalies of callose deposition and other cytological features of apospory and diplospory with those previously reported for bispory and tetraspory, and (iii) discuss the findings with regard to the evolution of apomixis and polyspory and the eventual transfer of apomixis to major crop species.
Crosses of sexual with aposporous genotypes of buffelgrass yielded segregation ratios compatible with an inheritance model that postulates expression of apospory requires the dominant allele (A) of a single autotetrasomically inherited locus, assuming random assortment of chromatids (Sherwood et al.
Moreover, the lack of aposporous embryo sacs in competition with MMCs, megaspores, or sexual embryo sacs also suggests the absence of apospory.