Continuity in Plant Life

Continuity in Plant Life

Ø How do you think plants reproduce?

By producing seeds or fruits or flowers.

Explain that asexual reproduction

® Involves simple division of the plant body into two or more parts or spore

formation.

® New plant body is formed from a single parent under favourable conditions.

Ø Why do you think that Spirogyra reproduces by fragmentation only and not

any other mode of reproduction such as seeds, flowers, etc.?

It does not have well developed body system.

Therefore it follows a simple way of reproduction like fragmentation.

explain the process of fragmentation in spirogyra.

Fragmentation- method of reproduction where the parent plant is divided into

two equal halves which grow into new individual plants.

Ø What does vegetative reproduction mean?

As the word- vegetative

suggests, it means reproduction from a part of the plant that is capable of

growth.

Explain depending on the part of plant that is used for reproduction,

 natural

methods of vegetative reproduction are further classified into three categories:

® Reproduction through roots

® Reproduction through stems

® Reproduction through leaves

Ø How does the ginger grow under the soil with respect to its orientation?

(horizontally)

plant that grows from ginger, would look like any other plant,

with branches, leaves, etc?

 (yes/no)

stems such as ginger, turmeric, canna are capable of growing a

new plant, these are called as rhizomes.

Ø What are these little growths on the margin of the leaf?

Buds or tiny leaves.

Ø Is it like any other leaf of plants you commonly see around?

(no, it has)

What do you think happens to these buds along the margin? (the buds get

detached from the main leaf and grow into new plant)

® A groups can present an interview with a Horticulturist.

 (an expert in different

methods of growing plants)

® A group can perform the role of stems and discuss how they grow.

     plants such as cactus, onion and lilies develop vegetative bulbs that

give rise to a new plant.

the horizontally running stem that gives rise to a new plant from it.

· Explain that such stems are called runners.

Ø Which leaf is this? (Bryophllum)

Ø What are these little growths on the margin of the leaf?

(buds or tiny leaves)

Ø Is it like any other leaf of plants you commonly see around?

 (no, it has)

Ø What do you think happens to these buds along the margin?

 (the buds get

detached from the main leaf and grow into new plant)

® A groups can present an interview with a Horticulturist

(an expert in different

methods of growing plants)

® A group can perform the role of stems and discuss how they grow.

Ø What are two types of vegetative reproduction?

(natural and artificial)

Ø How is natural method different than artificial method?

(natural method doesnot require human involvement, whereas in artificial method involves growth

from the vegetative part with human effort of planting it)

Ø Name the vegetative parts of the plants that are used in natural vegetative

reproduction?

 (roots, leaves and stems)

Ø Give examples of the plants that grow from roots?

 (radish, carrot, sweet potato)

Ø Give examples of the plants that grow from leaves?

(Bryophllum, Chinese tea

Ø Which plants are these? (rose)

Ø Are both plants same? (no)

Ø What is the difference between the two plants?

(one produces red colured

flowers while the other one has yellow flowers)

Ø If you have to grow these plants in your pots at home, how would you plant

them?

 (cut a young stem of the plant and plant it in moist soil)

Ø Suggest any other way by which one can grow rose plant?

 (purchase a sapling from green grower and plant it in a pot)

Ø If I want a plant which produces roses with shades of red and yellow, how

can I obtain such a plant?

 (Cut the stem of both the rose plants at appropriate sites and tie them together. After few months when the plant will

produce flowers they may show different types of variations in the colour)

Ø What are the reproductive parts of a flower?

(carpel and stamen)

Ø When a flower is called unisexual?

(when a flower contains only one

reproductive part- either carpel or stamen it is called as unisexual flower)

Ø Which parts of the flower are called as the male and female reproductive

parts respectively?

 (stamen is the male reproductive part while carpel is the

female reproductive part)

Ø What are the parts of a female reproductive part in the flower?

 (ovary at the bottom, middle elongated tube called as style and a terminal sticky partstigma)

Ø What does the male reproductive part do?

(it produces yellow coloured pollen grains)

Ø What do you think the petals and sepals do in a flower?

A flower is also referred as incomplete or unisexual flower when either of the

reproductive part is absent. While it is referred as a complete or bisexual flower

when both the reproductive parts are present.

Ø Why do you think some plants have brightly coloured flowers?

 (The brightly coloured flowers attract the insects and birds, which aid in pollination.

Whereas plants that have light coloured flowers, either self pollinate or have

other means of pollination like, wind or water)

Ø How do you think aquatic plants pollinate? (they release the pollens in the

water and with the water currents these pollens reach to distant places)

The received pollen grain is absorbed by the stigma in the pollen tube from

where it travels down and then enters the ovary.

· The male gamete from the pollen grain fuses with the female gamete (egg cell)

in the ovary. This process is called as fertilization.

· A zygote is formed as a result of fertilization.

® Ovule- the part of the ovary of seed plants that contains the female germ

cell and after fertilization becomes the seed

® Gametes- a mature male or female germ cell which is able to unite with

another of the opposite sex in sexual reproduction to form a zygote

® Zygote- A zygote is a single cell formed as a result of fusion of a male gamete

with the female gamete.

® Fertilization- the action or process of fertilizing an egg or a female plant,

involving the fusion of male and female gametes to form a zygote

Ø Why do you get to see same plants in different areas?

 (wind pollination takes

 Ø What would have happened if all the plants of same kind would grow in one

place?

 (the soil quality will be affected)

Ø How do plants like mosses, liverworts, ferns, etc. reproduce?

 (they form spores for reproduction)