Attractants and rewards are required for [2017]
entomophily
hydrophily
cleistogamy
anemophily
(1)
Entomophily is the most common type of zoophily where pollination takes place through the agency of insects. Entomophilous flowers are brightly coloured and secrete nectar to attract visiting insects.
Anemophily (wind pollination) and hydrophily (water pollination) do not require attractants or rewards due to the involvement of abiotic pollinating agents. Cleistogamy is self-pollination in closed flowers.
Flowers which have single ovule in the ovary and are packed into inflorescence are usually pollinated by [2017]
bee
wind
bat
water
(2)
Single ovule in the ovary and flowers packed into inflorescence are characteristics of wind pollinated flowers.
A dioecious flowering plant prevents both [2017]
autogamy and geitonogamy
geitonogamy and xenogamy
cleistogamy and xenogamy
autogamy and xenogamy
(1)
Dioecious plants are those plants in which male flowers and female flowers are borne on different plants. Therefore, they prevent both autogamy and geitonogamy.
In majority of angiosperms, [2016]
egg has a filiform apparatus
there are numerous antipodal cells
reduction division occurs in the megaspore mother cells
a small central cell is present in that embryo sac
Pollination in water hyacinth and water lily is brought about by the agency of [2016]
water
insects or wind
birds
bats
The ovule of an angiosperm is technically equivalent to [2016]
megasporangium
megasporophyll
megaspore mother cell
megaspore
(1)
The ovule of an angiosperm is equivalent to integumented megasporangium.
Which one of the following statements is not true? [2016]
Pollen grains of many species cause severe allergies.
Stored pollen in liquid nitrogen can be used in the crop breeding programmes.
Tapetum helps in the dehiscence of anther.
Exine of pollen grains is made up of sporopollenin.
(3)
Tapetum is the innermost wall layer of microsporangium that nourishes developing pollen grains.
Which of the following statements is not correct?
Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil.
Some reptiles have also been reported as pollinators in some plant species.
Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style.
Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers.
(3)
Pollen-pistil interaction is the group of events that occur from the time of pollen deposition over the stigma to the time of pollen tube entry into ovule. It is a safety measure to ensure that illegitimate crossing does not occur. Pollen grains of number of plants may settle over a stigma. The pollens belonging to same species would germinate while other fail to do so, but the pollen tube of the compatible pollen will grow through the style to reach the ovule whereas growth of incompatible pollens will be arrested at stigmatic disc or sometimes in the beginning part of style.
Proximal end of the filament of stamen is attached to the [2016]
placenta
thalamus or petal
anther
connective
Filiform apparatus is characteristic feature of [2015]
aleurone cell
synergids
generative cell
nucellar embryo
(2)
Filiform apparatus is a mass of finger-like projections of the wall into the cytoplasm. It is present in synergids (help cells) of the embryo sac, in the micropylar region. It guides the pollen tube inside the ovule towards the embryo sac.
