CBSE Questions for Class 12 Medical Biology Sexual Reproduction In Flowering Plants Quiz 14 - MCQExams.com

• Wind-pollinated flowers need to produce great quantities of pollen to be sure that at least some pollen grains will reach the stigmas of other flowers.
• These flowers are often small and inconspicuous since they do not need to attract insects. 
• They do not produce nectar and they do not have any scent. Most trees and grasses have wind-pollinated flowers. 
• Cross-pollination occurs when pollen is transferred from the anthers of one flower to the stigma of another flower. Self-pollination occurs when the pollen from the anther of a flower is transferred to the stigma of the same flower. 
• Cross-pollination is better than self-pollination. 
• When flowers are cross-pollinated their seeds germinate into strong, healthy plants. Seeds from self-pollinated flowers produce weaker, less healthy plants.

• F.R. Lillie proposed fertilization theory in 1914 which is based on sea urchins. 
• According to this theory, an egg (ovum) secretes a chemical called fertilizin and sperm on its surface a protein called anti-fertilizin. 
• The fertilizin of an egg interacts with the anti-fertilizin of the sperm of the same species. This interaction makes the sperms stick to the egg surface. 
• The adhesion of sperm to the egg of the same species through chemical recognition is known as agglutination.
• He showed that the sperm did not enter into the egg by simple mechanical boring. 
• Instead, the presence of the sperm calls forth a reaction on the part of the egg that leads to the absorption of the former. 
• Here, there is no copulation path where the male pronucleus will move on.

• The term “Xenia” was originally coined to refer direct effect of pollens on seed and fruit characters or effect of gene from male parent on development of fruit and seed. 
• However, as of now, it is restricted to denote effect of pollen grains on endosperms. For example- the colour of endosperm in Maize is determined by pollens. 
• Effect of pollen genes on fruit shape and fruit characters is known as metaxenia 

• Cleistogamous flowers have each male and feminine generative whorls and are closed even at maturity. They show self-fertility. 
• self-pollination may be a form of pollination during which the spore is transferred from the reproductive structure to the stigma of a same flower.
• Hence, cleistogamous flowers invariably show self-fertilization (autogamy).

When stamens are adnate or attached to the tepals, the condition is called epiphyllous.

A. When stamens are adnate to sepals, the condition is called episepalous.

B. When stamens are adnate to petals, the condition is called epipetalous.

C. When stamens are adnate to tepals, the condition is called epiphyllous.

D. When the anthers of the stamens are united and filaments are free, the condition is called synantherous or syngenesious.

Hence, the correct answer is 'Epiphyllous'

Stamens are the units of the androecium. These are male reproductive organs. Stamens bear anthers which contain the sporogenous tissues. The sporogenous tissues form the microspores that mature to develop into pollen grains. So, pollen grains are the microsporangium that bear the male gametes and stamens are the microsporophylls that bear the microsporangia.

A. Stamens represent microsporophylls.

B. Pollen grains represent microsporangia.

C. Ovule represents megasporangium.

D. Carpel represents megasporophyll.

Hence, the correct answer is 'Microsporophyll'

A. Correct option- D
B. Explanation for the correct option

Seeds, which store food materials in their cotyledons are called non- endospermic or exalbuminous seeds.

Seeds, which store food materials in their endosperm are called endospermic or albuminous seeds.

A. Cotyledons- It store food material in exalbuminous seed.

B. Hypocotyl- The portion of the axis between the radicle and cotyledonary node is called hypocotyl.

C. It is a persistent nucellus.

D. Endosperm- It store food material in the albuminous seed.

$$\textbf{Correct Option B}$$

$$\textbf{Solution}$$

$$\bullet$$ Bagging is the process of am emasculating the flower which is enclosed inside a bag in order to prevent the pollination by unwanted pollen.

$$\bullet$$This process is used during the artificial hybridization.This is done by covering the flower in a coil paper or polythene bag.

$$\bullet$$So, the correct option is B.

• Pollination in which the pollen is carried on an insect is called entomophily, and the flower is called entomophilous.
• Pollination of a flowering plant through the birds is called ornithophily.
• Chiropterophily is the pollination of plants by bats. Bat pollination is most common in tropical and desert areas that have many night-blooming plants. Just like bees and birds that pollinate, nectar-consuming bats have evolved ways to find and harvest sweet liquid.
• Humming birds help in the pollination of flowering plants, i.e., ornithophily.