Question 1

Question 1Distinguish between the following pairs :(a) Monocotyledonous and Dicotyledonous seeds(b) Epicotyl and Hypocotyl(c) Epigeal and Hypogeal germination(d) Radicle and Plumule(e) Albuminous and Exalbuminous seeds

Accepted Answer

(a) Difference between Monocotyledonous and Dicotyledonous seeds:Monocotyledonous seedDicotyledonous seedsSingle cotyledonTwo cotyledonsLarge endospermNo endosperm or less endospermPlumule leaves rolledPlumule leaves foldedHilum and micropyle not visible.Hilum and micropyle visible.Fruit wall and seed wall are fused.Seed are present inside the fruit separately.(b) Difference between Epicotyl and Hypocotyl:EpicotylHypocotylThe segment of the embryo or axis between the plumule and the cotyledons is known as epicotyl.The segment of the embryo or axis between radical and the cotyledons is called Hypocotyl.If the epicotyl elongates, the cotyledons remain underground and the germination is then called hypogeal germination.If the hypocotyl elongates, the cotyledons are pushed above the ground and the germination is then called epigeal germination.(c) Difference between Epigeal and Hypogeal germination:Epigeal germinationHypogeal germinationCotyledons are pushed above the ground.Cotyledons remain underground.Hypocotyl elongates faster.Epicotyl elongates faster.Usually occurs in dicotyledonous seeds.Usually occurs in monocotyledonous seeds.(d) Difference between Radicle and Plumule:RadiclePlumuleRadicle is the part of embryo that gives rise to the root.Plumule is the part of embryo that give rise to the shoot.Radicle is the first structure to emerge during germination.Plumule remains enclosed within the seed until germination occurs.Radicle grows downward into the soil and anchors the plant, absorbing water and nutrients from the ground.Plumule emerges from the seed and grows upwards, eventually developing into the stem and leaves of the plant.(e) Difference between Albuminous and Exalbuminous seeds:Albuminous seedsExalbuminous seedsCotyledons are thin and membranous.Cotyledons are thick and fleshy.Endosperm persists.Endosperm does not persist.

Question 2

Question 2What are the functions of the following in a seed?(a) Seed coat(b) Micropyle(c) Cotyledons(d) Radicle(e) Plumule

Accepted Answer

(a) Seed coat — A seed coat protects the delicate inner parts of the seed from injury and from the attack of bacteria, fungi and insects. It also plays a crucial role in regulating seed dormancy. The seed coat prevents premature germination by providing a barrier that restricts water and gas exchange.(b) Micropyle — It serves two functions:When soaked in water, the seeds absorb water mainly through the micropyle and make it available to the embryo for germination.It provides for the diffusion of respiratory gases for the growing embryo.(c) Cotyledons — Cotyledons contain food for the embryo and protect it.(d) Radicle — Radicle is the embryonic root of the plant. It grows downward into the soil and anchors the plant, absorbing water and nutrients from the ground. It develops into the primary root of the plant, which later gives rise to the entire root system.(e) Plumule — Plumule is the embryonic shoot of the plant. It grows upwards and is responsible for the development of the above-ground parts of the plant, including stems, branches, and leaves.

Question 3

Question 3Suggest an experiment to prove that a suitable temperature is necessary for germination.

Accepted Answer

Aim — To prove that a suitable temperature is necessary for germination.Apparatus — Two beakers, wet cotton wool, refrigeratorProcedure —(1) Take two beakers and label them as A and B.(2) Place some gram seeds on wet cotton wool in each of the beakers.(3) Keep beaker A at ordinary room temperature and beaker B in the refrigerator.(4) In 1-2 days, the seeds in beaker A will germinate, showing the importance of a suitable temperature for germination. Seeds in beaker B may not show the signs of germination or may germinate after several days, though not to the extent as the seeds in beaker A.Inference — Seeds require a suitable temperature for germination.

Question 4

Question 5Give two differences in each of the following pairs:(a) Coleorhiza and coleoptile(b) Bean seed and maize grain(c) Germination and vivipary

Accepted Answer

(a) Two differences between Coleorhiza and Coleoptile:ColeorhizaColeoptileProtective sheath of radicleProtective sheath of plumulePresent towards the pointed end of embryonic regionPresent towards the upper broader side of the embryonic region(b) Two differences between Bean seed and Maize grain:Bean seedMaize grainTwo cotyledonsOne cotyledonNo endospermLarge endosperm present(c) Two differences between Germination and vivipary:GerminationViviparyWhen the embryo in the seed becomes activated and begins to grow into a new plant, then it is known as germination.Vivipary is known as the germination of seed within the fruit, while it is still attached to the parent plant.Germination is a common and widespread method of plant reproduction.Vivipary is less common and is typically observed in plant species adapted to specific environments, such as wetlands or coastal areas.

Question 5

Question 6Justify the statement that the maize grain is a 'one seeded fruit'.

Accepted Answer

A fruit is the enlarged ripened ovary in which the ovarian wall forms the fruit wall and encloses the seed. The fruit protects the seed and helps in seed dispersal. The maize grain is regarded as a 'one-seeded fruit' because the fruit wall and the seed coat are fused to form a protective layer. Such a fruit is called grain.

Question 6

Question 8Draw a neat and labelled diagram of :(a) A twig of viviparous plant showing its germination.(b) A seedling growing in soil.

Accepted Answer

(a) Diagram of a twig of viviparous plant showing its germination:(b) Diagram of a seedling growing in soil:

Question 7

Question 9Draw a neat and labelled diagram of the 'Experimental set-up of three-bean seed experiment' and mention the necessity of each condition for the germination of seeds.

Accepted Answer

Experimental set-up of three-bean seed experiment is shown in the diagram below:The observations of the three-bean seed experiment are as follows:The middle seed germinates. It gets both oxygen and water.The top seed does not germinate at all. It gets only oxygen but no water.The bottom seed does not germinate or stops germinating after the emergence of a small radicle. It gets water but very little oxygen (from the air dissolved in water).Water, suitable temperature and air (oxygen) are necessary for germination.Water — Water is necessary because:By absorbing water, the seed swells and consequently the seed coat ruptures allowing the elongating radicle to come out and form the root system.Water is essential for chemical reactions and enzyme action on stored food in cotyledons or endosperm, converting it into a diffusable (dissolved) form for the developing embryo.Suitable temperature — A moderately warm temperature (25°C to 35°C) is usually favourable for germination which is also called optimum temperature. A very low temperature inhibits the growth of the embryo and a very high temperature destroys its delicate tissues.Oxygen — Oxygen is needed for respiration that provides energy for the rapid cell division and cell growth during germination.

Question 8

Question 1(x)The kind of germination in which the cotyledons remain underground is :Viviparous germinationEpigeal germinationVegetative germinationHypogeal germination

Accepted Answer

Hypogeal germinationReason — When epicotyl elongates, the cotyledons remain underground. This type of germination is known as Hypogeal germination.

Question 9

Question 1(xi)Seeds germinate in two ways. The type in which the cotyledons remain underground is called (P) ............... germination. During this type of germination, the (Q) ............... elongates faster.P — Epigeal, Q — HypocotylP — Epigeal, Q — EpicotylP — Hypogeal, Q — EpicotylP — Hypogeal, Q — Hypocotyl

Accepted Answer

P — Hypogeal, Q — EpicotylReason — In hypogeal germination, the cotyledons remain below the ground. The epicotyl elongates faster, pushing the plumule above the soil.

Question 10

Question 4Given below is the longitudinal section of a maize grain. Match the structures marked (a) to (e) with their correct functions/characteristics.Example: (f)-6: Separates the endosperm and the embryonic part.

Accepted Answer

L.S. of maize grainFunction characteristic(a) Radicle1. Develops into root system.(b) Plumule3. Later forms the shoot.(c) Scutellum (cotyledon)2. Single cotyledon.(d) Aleurone layer4. Rich in protein.(e) Endosperm5. Rich in starch.(f) Epithelium6. Separates the endosperm and the embryonic part.

Question 11

Question 7Match the terms given in column A with those of column B.Column AColumn BColeoptileRoot systemColeorhizaCotyledonRadicleRadiclePlumulePlumuleScutellumShoot system

Accepted Answer

Column AColumn BColeoptilePlumuleColeorhizaRadicleRadicleRoot systemPlumuleShoot systemScutellumCotyledon

Seeds - Structure and Germination

Long Answer Type

Multiple Choice Type

Very Short Answer Type