LESSON: Reproduction in Plants
When leaves and stems give rise to new plant what is it called?
Name the different types of asexual reproduction in plants.
· Vegetative propagation
· Spore formation
How do plants produce offspring?
Plants can reproduce in two ways:
i. Asexual reproduction
ii. Sexual reproduction
What are the two reproductive parts of a plant ?
Pistils and stamens present in the flower
Name the parts of a pistil.
Stigma, style and ovary
During pollination where do the pollen grains land on?
What are the two types of pollination?
Pollination is of two types; Self-pollination and Cross-pollination
If you plant a potato in the soil what will happen to it?
With favourable soil conditions the eye or the potato will give rise to buds that will develop into new plants.
What happens when yeast is added to warm water with sugar?
When yeast is added to warm water with a pinch of sugar, the sugar promotes asexual reproduction in yeast, which leads to rapid formation of buds and new yeast cells in a short time period.
How do slimy green patches on ponds spread so fast?
The slimy green patches seen on stagnant waters of a pond are algae. Under favourable conditions, the algae divide rapidly by fragmentation, where the parent alga breaks to form two or more fragments. These fragments then grow into new individuals and soon they cover the entire pond.
During the rainy season if you check the underside of a fern leaf what will you see?
During rainy season the ferns produce large number of spores which are seen as brown small particles under their leaves. These spores are a part of asexual reproduction and help in the spread and formation of new fern plants.
If you dust some pollen grains on the stigma of a flower in the same plant what kind of pollination would it be?
It would be cross pollination.
What are the advantages of seed dispersal?
Seed dispersal helps in
i. Preventing overcrowding around the parent plant
ii. Avoiding competition among the offspring for minerals, water and sunlight
iii. Finding new or foreign habitats and wider spread of the species
What is the unique characteristic of asexual reproduction?
Asexual reproduction is unique in the sense that it forms new plants without producing any seeds.
Draw and label the budding in yeast.
The small projection on the yeast cell is a bud, which grows, and later detaches itself from the parent body, forming a new cell, which in turn grows, and develops more yeast cells. Sometimes, a chain of buds are seen, which can rapidly produce a large number of yeast cells in a very short time.
Draw and label the reproductive parts of a flower.
Explain cross and self-pollination with a diagram?
The process of pollen transfer from anther (male part) to the stigma (female part) of a flower is called pollination. When the pollen grain falls on the stigma of the same flower the process is termed self-pollination. When pollen grains land on the stigma of a flower growing on the same plant or on a different plant of the same variety, the process is termed cross-pollination.
Explain fertilisation plants with a diagram?
Fertlisation is the fusion of a male germ-cell produced by the pollen grains, with the female gamete present in the ovary to form zygote. The steps involved in the process are:
1. Pollen is transferred from one flower to another with the help of wind, water or insects.
2. The pollen grain lands on the stigma and needs to reach the ovary for fertlisation. It does this with the help of a pollen tube which grows out of the pollen grain and travels through the style to reach the ovary.
3. The nucleus of the pollen grain fertilises the egg cell present in the ovary.
4. After fertilization, the fertilized egg cell (zygote) divides many times and forms an embryo.
Explain how a new rose plant will develop from a stem cutting.
When a cut branch of rose with a node is planted in the soil and watered regularly, it produces a new plant. This is a type of asexual reproduction which gives rise to new plant without a seed. In some plants such as the rose and champak, there are buds in the axil (the node, which is the point of attachment of the leaf to the stem) which produces new shoots. These buds are known as vegetative buds and consist of a short stem that is surrounded by immature, folded leaves that overlap each other. The vegetative buds can produce new plants.
Explain the seed dispersal methods.
Seed dispersal is the process of scattering seeds from the parent plant so that new plants have room to grow and do not compete for resources such as light, water and nutrients in the soil.
The common methods of seed dispersal are wind, water, animals and explosion.
Wind: Seeds from plants like dandelions, swan plants, grass and cottonwood trees are light and have feather structures. These can be easily carried by the wind to long distances. Example: Maple, Dandelion, Sunflower, Madar, etc.
Water: The plants that live near water have seeds that can easily float and carried by water. These seeds have floating ability. Examples are water lily, lotus, coconut etc.
Animal: Many animals help in the dispersal of seeds. Some plants have hooks or barb structure that get stuck into fur, feathers or skin of the animals and the seeds get carried away to distant places. Examples are Xanthium and urea.
Explosion: Some plants, like peas, gorse and flax, have seedpods that dry out once the seeds are ripe. When dry, the pods split open and the seeds scatter. Example: castor, ladyfinger, and balsam.