Q: Pollen grains are produced by

Solution Correct answer is option B. Explanation for correct option In plants, pollen grains are male gametophytes.Pollen is produced within the anthers (microsporangia or pollen sacs) of the flower.Pollen grains develop from sporogenous tissue in angiosperms.

Question 1

Identify each part in a flowering plant and write whether it is haploid (n) or diploid (2n).(a) Ovary (b) Anther (c) Egg (d) Pollen (e) Male gamete (f) Zygote

Accepted Answer

(a) Ovary - It is the female part of the plant which has ovules. It is a diploid (2n) structure.(b) Anther - It is the male part of the flower and contains pollen grain. It is a  diploid structure (2n).(c) Egg - Ovules are known as egg. It is female gamete present  in the ovary. It is a haploid structure (n).(d) Pollen - Pollens are male gamete. It is a haploid (n) gamete.(e) Male gamete - Pollens are male gamete. It is a haploid (n) gamete.(f) Zygote - It is formed by the fusion of male and female gamete. It is a diploid structure (2n).

Question 2

Differentiate between racemose and cymose inflorescence

Accepted Answer

Racemose inflorescence Cymose inflorescence This is an indefinite or indeterminate type of inflorescence This is a definite or determinate type of inflorescence The main axis does not end the growth with a flower The main axis ends the growth with a flower The flowers are borne in acropetal succession, that is, lower ones are older and upper ones are younger flowers The flowers are borne in basipetal succession, that is, lower ones are younger flowers and upper ones are older flowers Flowers are borne laterally  Flowers are borne terminallyThe opening of flowers occurs at short intervals Opening of successive flowers take long intervals

Question 3

Name the male and female reproductive parts in plants.

Accepted Answer

1) The male reproductive part in a plant is called stamen.It consists of anther and filament.The anther is a lobed structure which produces pollen grains.The filament is a slender stalk-like structure.2) The female reproductive part in a plant is called the pistil.It consists of three parts- stigma, style and ovary.The sticky part at the top called a stigma.A thin tube passing down is called a style.A swollen sac-like structure at the bottom is called an ovary. The pollen grains are transferred onto the stigma which then travels down the style into the ovary, where it meets with the ovules and fertilization takes place.

Question 4

Root pressure develops due to

Accepted Answer

Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day. Root pressure is caused by active absorption of mineral nutrient ions into the root xylem. Without transpiration to carry the ions up the stem, they accumulate in the root xylem and lower the water potential. Water then diffuses from the soil into the root xylem due to osmosis. Root pressure is caused by this accumulation of water in the xylem pushing on the rigid cells.Thus, the correct answer is option B.

Question 5

Describe the various types of placentations found in flowering plants.

Accepted Answer

Placentation refers to the arrangement of ovules inside the ovary. It is of five basic types:(A) Marginal placentation-The ovary in which the placenta forms a ridge along the ventral suture of the ovary and the ovules develop on two separate rows is known to have marginal placentation. This type of placentation is found in peas.(B) Parietal placentation-When the ovules develop on the inner walls of the ovary, the ovary is said to have parietal placentation.C) Axile placentation-In axile placentation, the placenta is axial and ovules are attached to it. Examples include China rose, lemon and tomato.(D) Basal placentation-The ovary in which the placenta develops from its base and a single ovule is found attached to the base is said to have basal placentation. It is found in marigold and sunflower.(E) Free central placentation-In free central placentation, the ovules develop on the central axis while the septa are absent. This type of placentation is found in Dianthus and primrose.

Question 6

Describe important features of family Solanaceae. Write its floral formula and economic importance.

Accepted Answer

It is a large family commonly called as potato family.Vegetative CharactersStem: herbaceous rarely woody, aerial, erect, cylindrical, branched, solid or hollow, hairy or glabrous, underground stem in potato.Leaves: alternate, simple, rarely pinnately compound, exstipulate; reticulate venation.Floral CharactersInflorescence: Solitary, axillary or cymose as in Solanum.Flower: bisexual, actinomorphic.Calyx: sepals five, united persistent, valvate aestivation.Corolla:petals five, united, valvate aestivation.Androecium: stamens five, epipetalous.Gynoecium:bicarpellary, syncarpous; superior ovary, bilocular, placenta swollen with many ovules.Fruits: berry or capsule.Seeds: Many, endospermousFloral formula:Economic Importance:-Medicinal plants:-belladonna, ashwagandha, datura(stramonium leaves dried and used as asthma medicine).Food plants:-various vegetables like the tomato, potato, brinjal etc are belongs to this family.Spice:-Chili.Tobacco plants which a source of alkaloid nicotine belongs to this family.Ornamentals:-Petunia is well known for its different colored flowers.

Question 7

What is venation? Give its types.

Accepted Answer

Venation is the phenomenon of arrangement of veins in the lamina of the leaf surface. It is of three types, reticulate, parallel and furcate venation. In reticulate venation, veins form the network like structure. For example, leaves of dicot plants. In parallel venation, veins arise from the mid rib and run parallel. For example, leaves of monocot plants. In furcate venation, veins form dichotomous branching. For example, leaves of fern.

Question 8

Pollen grains are produced by

Accepted Answer

Solution&#10;&#10;Correct answer is option B.&#10;&#10;Explanation for correct option&#10;&#10;In plants, pollen grains are male gametophytes.Pollen is produced within the anthers (microsporangia&#10;or pollen sacs) of the flower.Pollen grains develop from sporogenous tissue in&#10;angiosperms.&#10;&#10;&#10;&#10;

Question 9

Write the floral formula of a actinomorphic, bisexual, hypogynous flower with five united sepals, five free petals, five free stamens and two united carpels with superior ovary and axile placentation.

Accepted Answer

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Question 10

Differentiate between monocot and dicot with three examples. Draw necessary diagram.

Accepted Answer

Monocots Dicots Plants that have only one cotyledon in seeds are monocots Plants that have two cotyledons in seeds are dicots The floral parts are in multiples of three The floral parts are in multiples of four or five The pollen tube is monocolpateThe Pollen tube is tricolpate The leaves have parallel venation The leaves have reticulate venation Dorsiventral leaves are present Isobilateral leaves are present Stomata are present on both the upper and lower epidermis of leaves Stomata are more on the lower surface of leaves The adventitious root system is present The taproot system is present Vascular bundles in the stem are scattered.Vascular bundles in the stem are present in a ring. Secondary cambium is absent Secondary Cambium is present Secondary growth does not occur Secondary growth occurs dominantly These are the herbaceous plants These are both herbaceous and woody plants Sugarcane, wheat, rice, palm, etc are the examples Mango, mint, tomato, lettuce etc are the examples.