Perisperm differs from endosperm in
being a haploid tissue
having no reserve food
being a diploid tissue
its formation by fusion of secondary nucleus with several sperms
C.
being a diploid tissue
Perisperm is a nutritive tissue of a seed derived from the nucellus and deposited external to the embryo sac. It is remnants of nucellus which is diploid (2n) but endosperm is triploid (3n). It occurs in the seeds of Black perpper, coffee, castor etc. Endosperm is the food laden tissue which is meant for nourishing the embryo in seed plants. In angiosperms the endosperm is formed as a result of vegetative fertilization, triple fusion or fusion of a male gamete with diploid secondary nucleus of the central cell.
Emasculation ensures cross-pollination in
staminate flower
bisexual flower
neuter flower
pistillate flower
Monoecious plant of Chara shows occurrence of
antheridiophore and archegoniophore on the same plant
stamen and carpel on the same plant
upper antheridium and lower oogonium on the same plant
upper oogonium and lower antheridium on the same plant
Identify the correct pair of statements.
I. White kernal of coconut is a free nuclear endosperm.
II. In dioecious plants, autogamy is prevented but geitonogamy occurs.
III. Cleistogamous flowers are always selfpollinated.
IV. Castor is an endospermic seed.
II, IV
II, III
I, II
III, IV
In Zostera, the marine angiosperm, the pollen grains are long ribbon-like and without exine. They have same specific gravity as that of water. How is this feature helpful in their pollination?
The pollen grains become unwettable
The pollen grains spread over large and they are lighter
The pollen grains can float below the surface of water
None of the above
Cleistogamous flowers are
bisexual flowers which remain opened
bisexual flowers which remain closed
open female flower
open male flower
Advantage of cleistogamy is
higher genetic variability
more vigorous offspring
no dependence on pollinators
vivipary
