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Reproduction in Plants, Reproduction and Modes of Reproduction, , → It is a process of production of new individuals from their parents is known, as reproduction., Mode of reproduction:, → There are two modes of reproduction:, (i) Sexual reproduction, (ii) Asexual reproduction, , Sexual reproduction, , • Two parents are involved in this reproduction., • Fusion of a female and male cells produced gametes., • Parents and offspring are non-identical, • Variation is present in the same species.
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Asexual reproduction and its different Types, , → There is no need for production of seed to obtain new plant., → Single parents is involved in asexual reproduction., → There is no gametes produced., → The parent and offspring are identical., Different types of Asexual Reproduction:, (i) Vegetative reproduction, (ii) Budding, (iii) Fragmentation, (iv) Spore formation, ➢ Vegetative reproduction and its Advantages, , → New plants are produced from vegetative parts of plants like roots, stems,, leaves and buds, it is known as vegetative reproduction., • Advantages of vegetative propagation, → Method of propagation for seedless plants., → Exact copies of parent plant are produced., → Large numbers of offsprings are produced., → Disease free plants can be propagated., , 2
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➢ Budding, , → Small bulb-like cellular out growth called bud., → It is formed on parent cell that develops into an independent organism, called yeast., ➢ Fragmentation, , → Adult organism breaks into two or more pieces and forms a new individuals, called fragments., Examples: spirogyra, focus, , ➢ Spore formation, , → It is an asexual reproductive microscopic single or multi-celled spherical, bodies which germinate into new plants during favorable conditions., Examples: mosses, ferns, , 3
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Sexual reproduction in Plants, → A plant reproduces sexually with the help of flowers., Flower: Flower is a special organ of flowering plants, (angiosperms) which works as the reproductive, system., → Stamen and pistil are the reproductive parts of a, flower., → • Stamens: It is a male reproductive part., • Pistil: it is a female reproductive part., (i) Bisexual flowers: Flowers which contains both pistil and stamens are called, bisexual flowers., (ii) Unisexual flowers: Flower which contains either pistil of stamens is called, unisexual flowers., Different Stages of Sexual Reproduction in Plants are:-Pollination, -Fertilization, -Formation of fruits, -Seed dispersal, , ❖ Pollination, → It is a transfer of pollen grains from, anther to stigma of a flower is known as, pollination., → Pollination is a first step of seed, formation., Types of pollination, → There are two types of pollintaion:, (i) Self-pollination, (ii) Cross pollination, , (i) Self-pollination: In this pollination pollen grains are transferred from anther, to stigma of the same flower., (ii) Cross-pollination: In this pollination pollen grains are transferred from, anther of one flower to stigma of another flower., , 4
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❖ Fertilization, , → It is process of fusion of male gamete and female gamete is called, fertilization., → Fertilization produces zygote., → Zygote develops into an embryo., ❖ Formation of fruits and seed, , → After fertilization process the ovary enlarges to form the fruit., → Wall of ovary become the fruit wall., → Ovules become seeds., → The remaining part of the flower i.e., petals, sepals and other part usually, dry up and fall off., → Embryo enclosed in a protective seed coat., , ❖ Seed dispersal, , → It is a process by which seeds or fruits are scattered is called dispersal., Dispersal of Seeds, If all the seeds were to germinate near the mother plant, the new plants shall, not get adequate resources; like sunlight, air and nutrients. For proper growth, of the new plants, it is necessary that they develop away from the mother, plant. For this, it is necessary that seeds are spread far and wide. The, process of spreading seeds to different places is called dispersal of seeds., Many agents of seed dispersal assist the plants in this process., , 5
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Dispersal by Wind: Seeds of some plants are light-weight and some hair-like, or wing-like structures are present on them. Such seeds float on air and are, thus dispersed by wind. Example: Dandelion, maple, drumstick, etc., Dispersal by Water: Dispersal by water takes place in some aquatic plants, and in some which grow near a water body. Seeds of water lily float and thus, dispersed by water. The coconut seed has a tough fibrous covering which has, plenty of air inside. This helps the coconut seeds in floating on water., Dispersal by Animals: Some seeds have spine like structures on them. They, get stuck to the fur of animals and thus get spread to different places., Examples; Beggar tick, Xanthium, Urena, etc. Some seeds are swallowed by, birds and animals along with fruits. These seeds get dispersed with bird or, animal droppings., Dispersal by Bursting: Some fruits burst open when they mature. The force, of bursting is enough to spread the seeds. Examples; Ladyfinger, castor,, balsam, etc., Dispersal by Humans: Human beings also help in dispersal of seeds,, especially during farming., , 6
