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Unit-3, Flower to flower, In what respects, are the flowers different?, , , •, •, •, •, •, •, •, , Number of petals, Colour, Size, Shape, fragrance, Single flower/ inflorescence, Day blooming/ night blooming, , Parts of flowers
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Parts of flowers and their functions, Name of part, , Function, , Pedicel, , Connects the plant with the flower, , Thalamus, , Holds different parts of the flower, , Calyx, , Protects the flower when it is a bud., Holds petals after it blooms, , Corolla (Petals), , Provides colour, fragrance and, attractiveness to the flower, , Androecium, , Male reproductive part of the flower, , Gynoecium, , Female reproductive part of the, flower
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Reproduction in plants, Reproduction is the process by which organisms produce their young ones to, retain their ancestry. Flowers perform the function of reproduction in plants., , Sex organs in flowers, Androecium and gynoecium are the sex organs in flowers. Gynoecium has three, parts named ovary, style and stigma. Inside the ovary, ovules are found. Egg is, found inside ovule. Androecium is a group of stamens. Anther and filament are, the parts of stamen. Pollen grains are seen in anthers. Male, gametes are seen inside the pollen grains., , Unisexual and bisexual flowers, Flowers which have both androecium and gynoecim are called bisexual, flowers.Eg:- Hibiscus ( ചെമ്പരത്തി), Oleander ( അരളി ), Clitoria ( ശംഖുപുഷ്പം ),, Ladies finger ( വെണ്ട )
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In some flowers, either androecium or gynoecium is present. Such, flowers are called unisexual flowers., Eg:-Pumpkin, papaya, coconut, arecanut, snake gourd, , Male and female flowers, Flowers that have only androecium are male flowers and those with only, gynoecium are female flowers. Papaya, pumpkin, cucumber, bitter gourd,, snake gourd, ash gourd, coconut and arecanut trees have both male and female, flowers., , Male and female plant, Some plants bear male flowers only. They are called male plants. Some plants, bear female flowers only. They are called female plants. There are male and, female plants among fan palm ( കുടപ്പന ), gambooge ( കുടംപുളി ), nutmeg ( ജാതി ), etc., , Seed formation
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For the formation of fruits and seeds, the male gamete from the pollen grain, should reach the ovary and fuse with the egg. This involves two processes named, pollination and fertilization., Fertilization, Fusion of male gamete with the egg is called fertilization., Pollination, Transfer of pollen grains to the stigma is called pollination., Pollinating agents, Factors that help pollination are called pollinating agents., Eg:- Organisms like butterflies, honey bees, beetles, ants, flies, birds, bats, wind,, water etc., Peculiarities seen in flowers to attract pollinating agents, 1. Presence of honey, 2. Attractive colour, 3. Fragrance, 4. Night blooming flower have white colour and more fragrance, (Eg; Jasmine, nisagandhi), 5. Flowers in which pollinating agents are flies have foul odour, ( Eg:- Taro,elephantyam,rufflessia), 6. Small flowers are seen as inflorescence (Eg:-Lantana, ixora), 7. Tender leaves of non attractive flowers change their colour like petals, (Eg:- Mussaenda, Bouggainvillea), Pollination through wind and water, Wind is the pollinating agent of many plants., Eg:- Paddy, wheat, maize, sugarcane., Water is the pollinating agent in some aquatic plants like valisneria and, hydrilla. Water (dew drops) is the pollinating agent in pepper too. Flowers that, pollinate through wind and water have some, adaptations., Adaptations for flowers in which pollination happens through wind, • Have a large number of pollen grains, • Pollen grains are lighter in weight, Adaptations for flowers in which pollination happens through water, • Pollen grains have a wax coating, • Stigma is sticky, Match the following (Page 39), Light weight pollen grains, Colourful flowers, , -, , Wind, Honey bee
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White flowers that bloom at night, Pollination in pepper, , -, , Moth, Water (Dew drops), , Artificial pollination, Pollen grains from superior quality plants are collected and dusted on the stigma, of other plants to produce high quality seeds. This is artificial pollination. We, had to adopt artificial pollination to cultivate vanilla, as there is no melipona, bees in our country which are the pollinating agents of vanilla., Effective pollination, Pollination becomes effective when the pollen grains fall on the stigma of flowers, of the same, . Pollen grains that fall on the stigma of other kinds of flowers may get, destroyed., Eg:- If pollen grains of a pumpkin flower fall on the stigma of an ash gourd, plant, the pollination will not be effective., Self and cross pollination, There are two types of pollination named self pollination and cross pollination. If, pollination happens by reaching the pollen grains of a flower on the stigma of, the same flower or on the stigma of another flower of the same plant, it is called, self pollination. If pollination happens by reaching the pollen grains of a flower, on the stigma of another flower of another plant, it is called cross, pollination., Do both types of pollination occur in plants like cucumber, bitter gourd,, pumpkin etc.? Why?, No. Because they are unisexual flowers. Pollen grains and stigma are seen in, separate flowers in them, , Changes happening to flowers after pollination, Parts of the flower, , Change, , Pedicel, Calyx, Corolla, Androecium, Ovary, Ovules, , Becomes thicker and stronger, Becomes thicker and stronger, Withers, Withers, Becomes fruit, Becomes seed
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Thalamus, , Becomes thicker and stronger, Types of fruits, , Simple fruits, In some plants, only one fruit is formed from each flower. These fruits, are called simple fruits., Eg:- mango, ash gourd, tomato, coconut, rice, papaya, ladies finger., Aggregate fruits, In some plants, more than one fruit is formed from a flower. Such, fruits are called aggregate fruits. Eg:- custard apple, black berry,, polyalthia fruit, frangipani, strawberry., Multiple fruits, In some plants, many flowers are arranged on a common stalk. After, fertilization, fruits are formed from each of these flowers and are, arranged inside a common covering. Such fruits are called, multiple fruits. Eg:- Jack fruit, pineapple, noni fruit., What is chakkachula, chakkukkuru and chakkachavini in a jackfruit?, In jackfruit, chakkachulas are the fruits, chakkakkurus are the seeds, and chakkachavinis are the flowers in which pollination failed., False fruits, In some plants, parts like the pedicel, thalamus etc., develop into fruit, like structures. These are called false fruits. Eg:- cashew apple, (pedecil), apple (thalamus), pear (thalamus), Explain the advantage of false fruits based on seed dispersal., In false fruits, the real fruits are not fleshy. Instead, the false fruits are, fleshy. The birds and bats that help in seed dispersal will take these, fruits, eat the fleshy part and leave the seeds., Examine the figures given in page 43 of the text book and find out the, right statement related to each fruit., Strawberry - More than one ovary in a flower, Chilli - Flowers are seen ony by one (single flower), Arecanut - Flowers Are seen as inflorescence, , Let us assess
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1. Observe the picture. What inferences can be made, about bitter gourd flower, , , , • It has one ovary, • It’s ovary is elongated, • It’s ovary contains many ovules, 1. Parts like petals, androecium etc., wither and fall down after, fertilization. The pedicel, thalamus and calyx become stronger., Explain the reason., Petals are to attract pollinating agents and androecium is to provide, pollen grains. So they are useless after pollination. The pedicel,, thalamus and calyx become stronger because, they have to hold the, fruit.
