ہمارے اسکول کئ لائبرئرئ مضمون لکھے
Answers
Explanation:
In case of Hydra, under favourable
conditions, at specific part of its body, an
outgrowth is formed by repeated divisions of
regenerative cells of body wall. This outgrowth
is called as bud. Bud grows up progressively
and finally forms a small hydra. Dermal layers
and digestive cavity of the budding hydra are
in continuity with those of parent hydra. Parent
hydra supplies nutrition to the budding hydra.
Budding hydra separates from parent hydra and
starts to lead an independent life when it grows
up and becomes able to lead an independent life.
4. Vegetative Propagation
Reproduction in plants with the help of
vegetative parts like root, stem, leaf and bud is
called as vegetative reproduction. Vegetative
propagation in potatoes is performed with
the help of ‘eyes’ present on tuber whereas in
Bryophyllum it is performed with the help of buds
present on leaf margin. In case of plants like
sugarcane & grasses, vegetative propagation
occurs with the help of buds present on nodes.
5. Spore Formation
Take a piece of wet bread or ‘bhakari’ and
keep it in humid place. Fungus will grow on it
within 2 – 3 days. Observe the fungus under
compound microscope and draw its diagram.
Fungi like Mucor have filamentous body. They
have sporangia. Once the spores are formed,
sporangia burst and spores are released. Spores
germinate in moist and warm place and new
fungal colony is formed.
Sweet
Potato
Bryophyllum
Potato
Hydra Bud
Nascent Hydra
3.9 Budding
3.10 Vegetative
reproduction
Sexual Reproduction
Sexual reproduction always occurs with the help of two germ cells. Female gamete and
male gamete are those two germ cells. Two main processes occur in the sexual reproduction.
1. Gamete formation: Gametes are formed by the meiosis. In meiosis, chromosome
number is reduced to half; hence haploid gametes are formed.