Nucellar polyembryony is reported in species of
Gossypium
Triticum
Brassica
Brassica
D.
Brassica
The occurrence of more than one embryo in a seed is referred as polyembryony. In many Citrus and mango varieties, some of the nucellar cells surrounding the embryo sac and develop into the embryos in such species each ovule contain many embryos (nucellar polyembryony).
In which one of the following pollination is autogamous?
Xenogamy
Chasmogamy
Cleistogamy
Cleistogamy
C.
Cleistogamy
Bisexual flowers which remain always closed are called the cleistogamous and such condition of flowers is called cleistogamy. In such flowers, the anthers and stigma lie close to each other. When anthers dehisce in the flowers buds, pollen grains come in contact with stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous.
Apomictic embryos in Citrus arise from
Synergids
maternal sporophytic tissue in ovule
antipodal
antipodal
B.
maternal sporophytic tissue in ovule
Substitution of usual sexual reproduction by a form of reproduction which does not involve meiosis and syngamy is called apomixis. In Citrus, apomictic embryo arises from diploid cells. (maternal sporophytic tissue) of the ovule occurring outside the embryo sac.
In angiosperms, functional megaspore develops into
embryo sac
ovule
endosperm
endosperm
A.
embryo sac
In angiosperms, the unit of female gametophyte (embryo sac) is functional megaspore.