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REPRODUCTION IN
LOWER AND
HIGHER PLANT
Mcq

Q
...
Name the part of gynoecium that determines the compatible nature of pollen grain
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How many haploid cells are present in a mature embryo sac ?
ANS : An unfertilized embryo sac of angiosperm is composed of 7 cells i
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, 7-celled and
8-nuclei
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3
...

4
...
It
occurs inside the nucellus of ovule of angiosperm
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5
...
Some plants
distribute their pollen to the surface of water and some plants distribute pollens
beneath the surface of water
...
Name the layer which supplies nourishment to the developing pollen grains
...
It provides nourishment to the
developing pollen grains

7
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ANS: Parthenocarpy is the development of fruit without the formation of seeds due to lack of
pollination, fertilization and embryo development
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Such fruits are seedless
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8
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Pollination and
fertilization are not necessary in apomixis

9
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ANS: A pistil has three parts , i
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, stigma (receives pollen), which grows down through style to ovary
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The ovary develops into the fruit and ovule develops
into a seeds

10
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Q
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How polyembryony can be commercially exploited ?
ANS :
• It offers consequent result of multiple seedlings in an emergency
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• It makes to improve the probability of survival under different conditions
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2
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Justify the
statement
ANS :
• TRANSFERENCE OF POLLEN GRAIN FROM THE ANTHER TO THE STIGMA IS POLLINATION
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• THEN ONLY FERTILISATION OCCURS
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OVARY
INTO FRUIT
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WITHOUT THESE PROCESSES FRUITS are NOT
FORMED
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Incompatibility is a natural barrier in the fusion of gametes
...

• Prezygotic isolation mechanisms are defined as the mechanisms which prevent the
formation of zygote between incompatible organisms
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• Hence, incompatibility act as a natural barrier for fusion of gametes to prevent
reproduction between individuals of different species
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Describe three devices by which cross pollination is encouraged in
Angiosperms by avoiding self pollination
...
e
...

• Self-incompatibility: A genetic method to prevent pollens from fertilizing ovules of the
same flower by inhibiting their germination on stigma or pistil
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e
...

• This prevents both autogamy and geitonogamy
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4 Long Answer Questions :
1
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The
flowers form the reproductive part of angiosperms with separate male and female reproductive
organs
...
Pollination helps the pollen grains to
reach stigma via style
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This proceeds to
fertilization
...

• Double fertilization is a complex process where out of two sperm cells, one fuses with the egg cell
and the other fuses with two polar nuclei which result in a diploid (2n) zygote and a triploid (3n)
primary endosperm nucleus (PEN) respectively
...

• Eventually, the primary endosperm nucleus develops into the primary endosperm cell (PEC) and
then into the endosperm
...


2
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This process is called microsporogenesis
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These
are now called microspores or pollen grains
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differentiates into pollen grain
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• The partition walls between the sporangia get destroyed and the microspores are
liberated by the dehiscence of the anther
...
Explain the development of dicot embryo
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The cell
towards the micropylar end of the embryo sac is the suspensor cell (i
...
, basal cell) and the
other one makes to the embryo
...
e
...
The terminal cell by subsequent divisions gives rise to the embryo
while the basal cell contributes the formation of suspensor
...
In
certain plants the basal cell also forms the hypocotyl (i
...
, the root end of the embryo) in
addition of suspensor
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Now each of the four cells divides transversely forming the
octant stage (8-celled) of the embryo
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• The epibasal octants give rise to plumule and the cotyledons, whereas the hybobasal
octants give rise to the hypocotyl with the exception of its tip
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The
outer cells divide further by anticlinal division forming a peripheral layer of epidermal cells,
the dermatogen
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• The cells of periblem give rise to the cortex while that of plerome form the stele
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• The suspensor pushes the embryo cells down into the endosperm
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The lowermost cell of the suspensor is known as hypophysis
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• With the continuous growth, the embryo becomes heart-shaped which is made up
of two primordia of cotyledons
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• Each cotyledon appears on either side of the hypocotyl
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4
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S
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• Antipodals degenerate

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