FRANK Solutions for Class 9 Biology Chapter 8 - Pollination and Fertilization
Learn about the adaptations in pollinated plants with our Frank Solutions for ICSE Class 9 Biology Chapter 8 Pollination and Fertilization. Understand self-pollination and cross-pollination with relevant examples. Also, revise the solutions to learn to explain the function of a pollen tube with a supporting diagram.
Revise the critical topic of double fertilization with TopperLearning’s Frank textbook solutions. ICSE Class 9 Biology study materials like online practice tests, video lessons, solved question papers are also available on our e-learning portal. These resources are created by experienced teachers and will further help you to excel in your Biology exam.
Chapter 8 - Pollination and Fertilization Exercise 72
The male gametes are produced inside pollen grains located in the anthers of androecium whereas the female gametes are produced in the ovules located in the ovary of gynoecium. For forming zygote, the male gametes need to be transferred to the gynoecium for fusing with the female gametes. This is achieved through pollination. Pollination occurs through insects, wind or other agents.
There are two types of pollination - Self pollination and cross pollination.
(i) Self-pollination - It is the transfer of pollens produced within the anther of a flower to the stigma of the same flower or to the stigma of another flower of the same plant. In such flowers, pollination is ensured since the flowers bear similar genetic characters. Self pollination can occur in bisexual or monoecious flowers. Examples of plants showing self pollination are Mirabilis, Arachis etc.
(ii) Cross pollination - It is the transfer of pollen grains from the anthers of a flower of one plant to the stigma of a flower of another plant. Cross pollination occurs in unisexual or dioecious flowers such as papaya, maize, jasmine, rose etc.
(i) Bisexuality - Self pollination occurs only in bisexual flowers.
(ii) Homogamy - Both anther and stigma need to mature at the same time.
(iii) Cleistogamy - Flowers which are bisexual and never open are called cleistogamous flowers. They are small, colourless, odourless and without nectar. The pollen grains fall on the stigma inside the closed flower. Example - Arachis
Adaptations required by cross pollinated plants are:
(i) Unisexuality - The stamens and carpels are found in different flowers. The male and female flowers may be borne on the same or different plants.
(ii) Dichogamy - In bisexual flowers, stamens and carpels mature at different times. It is of two kinds:
(a) Protandry wherein stamens mature before carpels. E.g - jasmine
(b) Protogyny wherein carpels mature before stamens. E.g. - Rose
(iii) Heterostyly - Here the style is either longer or shorter, thereby preventing self pollination.
(iv) Herkogamy - Stigma and stamen mature at the same time, but some type of barrier prevents self pollination. E.g. - In caryophyllaceous flower, the stigma projects beyond the stamens so that pollens cannot fall on it.
(v) Self-sterility - Pollen of one flower cannot fertilize the female gametes of the same flower.
Significance - Due to double fertilization, triploid nucleus develops into endosperm which serves as nutrition for embryo.
(i) The ovules develop into seeds
(ii) The ovary walls thicken and ripen into pericarp or fruit wall.
(i) Pollination by insect is known as
(d) none of these
(ii) Chiropterophily means pollination by
(iii) Pollination carried by birds is
(iv) One male gamete fuses with the egg and forms a diploid zygote. This process is called
(b) triple fusion
(d) none of these
(v) The study of fruits is known as
(vi) When only ovary forms fruits they are known as
(a) false fruits
(b) true fruits
(d) none of these
(ii) (a) bats
(iii) (a) ornithophily
(iv) (a) syngamy
(v) (c) pomology
(vi) (b) true fruits
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