Autogamy can occur in a chasmogamous flower if
1. pollen matures before maturity of ovule
2. ovules mature before maturity of pollen
3. both pollen and ovules mature simultaneously
4. both anther and stigma are of equal lengths
1. | Cleistogamous flowers always exhibit autogamy |
2. | Chasmogamous flowers always exhibit geitonogamy |
3. | Cleistogamous flowers exhibit both autogamy geitonogamy |
4. | Chasmogamous flowers never exhibit autogamy |
Q. 12 A particular species of plant produces light, non-sticky pollen in large numbers and its stigmas are long and feathery. These modifications facilitate pollination by
1. insects
2. water
3. wind
4. animals
From among the situations given below, choose the one that prevents both autogamy and geitonogamy.
1. Monoecious plant bearing unisexual flowers.
2. Dioecious plant bearing only male or female flowers.
3. Monoeciousplant with bisexual flowers.
4. Dioecious plant with bisexual flowers.
In a fertilised embryo sac, the haploid, diploid, and triploid structure are
(1) synergid, zygote and primary endosperm nucleus
(2) synergid, antipodal and polar nuclei
(3) antipodal, synergid and primary endosperm nucleus
(4) synergid, polar nuclei and zygote
In an embryo sac, the cells that degenerate after fertilisation are
1. synergids and primary endosperm cell
2. synergids and antipodals
3. antipodals and primary endosperm cell
4. egg and antipodals
While planning for an artificial hybridisation programme involving dioecious plants, which of the following steps would not be relevant?
1. Bagging of female flower
2. Dusting of pollen on stigma
3. Emasculation
4. Collection of pollen
In the embryos of a typical dicot and a grass, true homologous structures are
1. Coleorrhiza and coleoptile
2. Coleoptile and scutellum
3. Cotyledons and scutellum
4. Hypocotyle and radicle
The phenomenon observed in some plants wherein parts of the sexual apparatus is used for forming embryos without fertilization is called
1. parthenocarpy
2. apomixis
3. vegetative propagation
4. sexual reproduction
In a flower, if the megaspore mother cell forms megaspores without undergoing meiosis and if one of the megaspores develops into an embryo sac, its nuclei would be
1. haploid
2. diploid
3. a few haploid and a few diploid
4. with varying ploidy