Page 104 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

11. Reproduction in Plants

Chapter in a Nutshell

v The process by which organisms produce new organisms of its own kind is called reproduction.
v The various methods by which plants reproduce are–asexual reproduction and sexual
reproduction.

v The mode of reproduction where a new offspring is produced by a single parent is called
asexual reproduction. offspring reproduced by this method is geneticaly similar to the

parent organism.
v Vegetative propagation is a type of asexual reproduction in which the vegetative parts of the

plants, such as roots, stems, leaves and buds give rise to new plants. Vegtetive propagation
can be done through natural or artificial methods.

v Natural vegetative propagation occurs naturally in plants without any human interference
by leaves, by roots or by stems. For example,
(a) in Bryophyllum, small plantlets arise at leaf tip which when reach the soil, grow into

a new plant.

(b) Plants, such as sweet potato have swollen roots, also called tuberous roots which
develop into adventitious buds that grow into new plants.

(c) Like roots, underground modified stems also help in developing new plants. These
include tuber, rhizome, bulb, etc.

Artificial methods of vegetative propagation are.

(a) Cutting is a method in which a cutting from a plant is taken & planted to grow new
plants. For example, rose.

(b) Grafting is similar to cutting except that the cut part of the plant is attached to another
rooted plant of similar variety. For example, apple.

(c) Layering is a method where a mature branch of the parent plant is bent down in the

soil. It develops into a new plant. For example, strawberry.
(d) Tissue culture is the cultivation of plant cells, tissues or organs in specially formulated

nutrient media. It is also called micropropagation & is widely used in forestry &

horticulture.
v Budding is a type of asexual reproduction which is seen in unicellular organisms. Yeast cell

produces a bud which develops & then detaches from the mother cell to produce a new

yeast cell.

104