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![Ans: Vegetative Propagation : The reproduction which occurs with the help of vegetative oprgans like root, stem, leaves or buds
is called vegetative propagation.
Natural methods of vegetative propagation
A]By tuberous roots: In some plants roots are swollen due to storage of food material. These tuberous roots bear adventitious
buds on their surface which under favourable conditions sprout to produce leafy shoots and slips.It is seen in sweet potato,
asperagus, dahlia.
B] By stem tubers: It is underground modification of stem. It bears number of notches on its surface called eyes. The eye is
actually a node bearing one or more small axillartybudsand reduced scaly leaves.One of the axillary bud sprout and give rise to a
new plant. Eg: potato
C] By runner: the runner is subaerial slender branch which creeps horizontallyon the ground and become rooted at the nodes.
Shoots which are produced from upper isdes of the nodes get detached from the parent plant and grow as a independent plant.
Example: cynodon, Fragaria, Oxalis.
D] By leaf buds: In plants like bryophyllum, Kalanchoe and Begonia vegetative propagation occurs with the help of leaf buds. In
bryophillum leaf bears buds in its notched margins. These buds sprout on the leaf to form leafy shoots and adventitious roots which
on separation fall on the wet soil and develop into a new plant.
8. Draw a neat well labeled diagram of Anatropous ovule. (3m)
Ans: refer Q No 2.
9. Give significance of double fertilization. (3m)
Ans: Significance of double Fertilization:
1. Double fertilization leads to the formation of triploid endosperm which ensures better nourishment of the developing
embryo.
2. Double fertilization leads to the formation of an embryo which gives rise to a new plant.
3. Double fertilization is essential for formation of viable seeds.
4. Double fertilization restores diploid condition by the fusion of 2 haploid gametes.
5. Double fertilization brings about the recombinations of characters.
6. Double fertilization stimulates the ovule as a result of which the ovule is converted into the seed and the ovary is
converted into the fruit
10. Explain the development of dicot embryo in angiosperms.
Ans:
1. The development of embryo from a zygote is called embryogenesis.
2. The fusion of male gamete and an egg cell during fertilization results in formation of diploid zygote.
3. The zygote develops a wall around it and is converted into oospore.
4. The oospore undergoes a transverse division to form a large basal cell towards the micropyle and a small
apical cell towards the interior of the embryo sac. This 2 celled structure is called embryosac.
5. The basal cell undergoes repeated transverse divisons to form multicellular structure called suspensor.
6. The suspensor pushes the embryo towards the endosperm to draw its nutrition.
7. The apical cell of the proembryo undergoes a transverse division followed by 2 vertical divisions at right angle
to form an octant stage.
8. The octant forms 8 smaller cells and 8 larger cells.
9. The cells of outer layer forms epidermis.
10. The cells of the inner layer gives rise to an embryonal mass which on differentiation form procambium and
ground meristem.](/proxy?url=https%3A%2F%2Fimage.slidesharecdn.com%2F1-reproduction-in-plants-assignment-notes-250109084333-950b3c86%2F85%2F1-reproduction-in-plants-assignment-notes-pdf-4-320.jpg)
![11. The procambium and ground meristem undergo differentiation and form an embryonal axis consisting of
plumule, a radical and 2 cotyledons.
11. Give functions of tapetum& Suspensor.
Ans: Tapetum:Tapetum is important for the nutrition and development of pollen grains, as well as a source
of precursors for the pollen coat.
Suspensor:The suspensor helps in pushing the embryo into the endosperm. The suspensor functions early
in embryogenesis to provide physical support, nutrition, and growth regulators for proper development of
embryo.
12. Give floral adaptations of anemophily, ornithophily, chiropterophily&entamophily. (3m)
Ans: Anemophily:
1. The transfer of pollen grain through wind is called wind pollination.
2. Plants that are pollinated by wind are called as anemophilous plants.
3. Animophilous plants bear small & inconspicuous flowers without any bright colours fragrance and
nectar.
4. Flowers are produced in large numbers
5. Stamens are long with versatile anthers.
6. Stigma is feathery to receive pollen grains coming along with the wind.
7. Example: grass, maize, Jowar& sugarcane.
Ornithophily:
1. The transfer of pollen grain through birds is called ornithophily.
2. Plants that are pollinated by wind are called as ornithophilous plants.
3. Ornithophilous plants bear large and fleshy flowers.
4. Flowers are brightly coloured to attract birds for pollination
5. Ornithophilous flowers lack fragrance as birds have poor sense of smell.
6. Pollen grains are sticky.
7. Example: Callistemon, Bignonia, Bombax, Butea.
Chiroterophily;
1. The transfer of pollen grain through bats is called ornithophily.
2. Plants that are pollinated by bats are called as chiroterophilous plants
3. Bat-pollinated flowers tend to be large and show, white or light coloured, open at night and have
strong musty odours.
4. They are often large and bell-shaped or a ball of stamens.
5. Flowers are typically borne away from the trunk or other obstructions
6. Example:Adansonia, kigellia.
Entamophily:
1. The transfer of pollen grain through insects is called entamophily.
2. Plants that are pollinated by insects are called as entamophilous plants.
3. Flowers are large and attractive.
4. When small, flowers are clustered in a n inflorescence.
5. Flowers are brightly coloured with pleasant smell
6. Flower produce nectar which is food for insects.
7. Poleln grains are spiny and sticky for easy adherence to stigma.
8. Example: Hibiscus, rose, mogra.
[ each pollination can be asked for 3/2 marks example is necessary, can be asked as diference between also]
Hydrophily
Hydro means water and phily means affinity. Hydrophily are water pollinated plants. One example is Vallisneria.
The characteristics of water-pollinated plants are:
- Pollen grains are produced in large numbers.
-The weight of the pollen grains is equal to that of water. That is why they float on the surface of water.
-The pollen grains continue to float on the surface of water till they meet the female flowers. The same procedure is
followed in the water pollinated flower called Vallisneria.](/proxy?url=https%3A%2F%2Fimage.slidesharecdn.com%2F1-reproduction-in-plants-assignment-notes-250109084333-950b3c86%2F85%2F1-reproduction-in-plants-assignment-notes-pdf-5-320.jpg)
![3. It is more economical because they do not have to develop large, attractive flowers, fragrance nectar
& honey etc.
4. There is least wastage of pollen grains during self pollination.
5. Genetic stability is maintained in the progeny.
6. Pure line plants can be preserved through self pollination.
7. Improved varieties of plants can be multiplied by preserving their desirable characters.
Dichogamy favors cross pollination
Maturation of stigma and anther at different times is called dichogamy. As they do not mature together they
can’t self pollinate. Hence dichogamyfavours cross pollination.
It is of 2 types:
A] Protandry : In plants like sunflower pollen grains are mature much before stigma, such plants are called
protandry.
B] Protogyny: : In plants like Michelia stigma get mature much before pollen grains, such plants are called
protogyyny..
17. Formation of primary endosperm nucleus is called triple fusion. Give Reason.
Ans: 1. Triple fusion is the fusion of the male gamete with two polar nuclei inside the embryo sac of the angiosperm.
2. This process of fusion takes place inside the embryo sac.
3. One male gamete nucleus and two polar nuclei are involved in this process.
4. When pollen grains fall on the stigma, they germinate and give rise to the pollen tube that passes through the style and enters
into the ovule.
5. After this, the pollen tube enters one of synergids and releases two male gametes there.
6. Out of the two male gametes, one gamete fuses with the nucleus of the egg cell and forms the zygote (syngamy).
7. The other male gamete fuses with the two polar nuclei present in the central cell to form a triploid primary endosperm
nucleus.
8. Since this process involves the fusion of three haploid nuclei, it is known as triple fusion. It results in the formation of the
endosperm.
18. Sketch & label T. S of angiospermic anther.
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1-reproduction-in-plants-assignment-notes.pdf
The document provides a detailed overview of plant reproduction, focusing on angiosperms, including the structure of pollen grains and anatropous ovules, as well as the process of double fertilization. It discusses various methods of vegetative propagation and the significance of double fertilization in forming viable seeds and nourishing the developing embryo. Additionally, it covers different pollination types, advantages and disadvantages of self- and cross-pollination, and the formation of the primary endosperm nucleus through triple fusion.
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