Directions: In the following questions, a statement of assertion is followed by a statement of reason.
Mark the correct choice as:
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.
Q.1. Assertion : Apical meristem of root is subterminal.
Reason : At the terminal end of root, root cap is present.
AnswerAnswer: (a) Root cap is the terminal part of root.
Q.2. Assertion: Fibrous root stem.
Reason: Fibrous root system is found in dicots only.
AnswerAnswer: (c) A number of thin, thread-like branched roots develop from the base of the stem in fibrous root system. The roots are of nearly equal size. They form a bunch which helps in holding the soil firmly. It provides good anchorage to the plant, helps in proper absorption of water and minerals. This root system is found in many monocots. Examples of plants having fibrous root system are wheat and barley.
Q.3. Assertion : Ginger has a prostrate-growing rhizome.
Reason : Shoot growth is not effected by gravity.
AnswerAnswer: (b) Ginger is horizontal in position and generally branched and producing aerial leaves or shoots above ground and adventitious roots on lower side in favourable season. Thus, shoot growth is not effected by gravity.
Q.4. Assertion: Avicennia has pneumatophores.
Reason: Pneumatophores help the plant to get oxygen for respiration.
AnswerAnswer: (a) In plants such as Avicennia, growing in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots are called pneumatophores which help to get oxygen for respiration. These roots are also known as respiratory roots.
Q.5. Assertion: Roots do not possess nodes but no leaves or buds.
Reason: Root branches arise endogenously.
AnswerAnswer: (b) Root is typically a non green underground cylindrical structure forming the descending axis of the plant which gives rise to endogenous branches and does not possess nodes, leaves or buds. Presence of nodes and internodes is the characteristic feature of stems.
Q.6. Assertion: Root caps are absent in floating aquatic plants.
Reason: Root pockets are present in aquatic plants.
AnswerAnswer: (b) The root cap protects the root meristem from friction of the soil particles. In the process, its outer cells are continuously peeled off and replaced by new cells formed from root meristem. In floating aquatic plants, the root apices possess finger glove-like coverings called root pockets instead of root cap.
Q.7. Assertion: Root pockets are very similar to root caps.
Reason: Root caps and root pockets have the ability to regenerate.
AnswerAnswer: (d) Root pockets are present in floating aquatic plants. They act as balancers. They are structurally similar to root caps but differ from them, in the fact, that the damaged root pockets are not regenerated. Pandanus, possess multiple root caps with a number of sheaths found successfully one after the other because they are not peeled off in the absence of soil friction.
Q.8. Assertion: Root hairs are not present on whole of root surface.
Reason: Root hairs absorb water.
AnswerAnswer: (b) Root hair zone is 1-6 cm in length. The root hairs increase the exposed surface of the root for absorption of water and minerals.
Q.9. Assertion: Deep feeder tap root system is called racemose tap root system.
Reason: It is found in trees.
AnswerAnswer: (a) Deep feeder tap root system has an elongated tap root which penetrates the deeper layers of the soil. It is mostly found in trees. Deep feeder tap root is also called racemose tap root system. In surface feeders, the tap root does not elongate very much. The secondary roots spread to a greater extent. Such a system is also named as cymose tap root system.
Q.10. Assertion: Orchis root resembles human hand.
Reason: It is an example of fasciculated fleshy roots.
AnswerAnswer: (c) The fleshy roots are thickened like the palm of human hand. They similarly possess finger like outgrowth, e.g., Orchis. They are palmate roots. Fasciculated fleshy roots are the swollen roots or root tubers occurring in clusters.
Q.11. Assertion: Momordica roots look like necklace.
Reason: Momordica possess moniliform roots.
AnswerAnswer: (b) Moniliform of beaded roots are swollen at regular intervals like beads of a necklace. Hence, the roots have the appearance of necklace. Such roots are found in Discorealata, Momordica charauter etc.
Q.12. Assertion: Assimilatory roots can photosynthesize.
Reason: Assimilatory roots possess chlorophyll.
AnswerAnswer: (a) Assimilatory roots are green roots (as they contain chlorophyll) which are capable of photosynthesis. e.g., Taeniophyllum, is a leafless epiphytic orchid with thick flattened photosynthetic roots.
Q.13. Assertion: Epiphytes are called space parasites.
Reason: Their roots possess velamen.
AnswerAnswer: (b) Epiphytes live on the surface of other plants for shelter and space only, hence are also called space parasites. Epiphytic roots possess a covering of dead spongy tissue known as velamen. They are able to absorb water from moist atmosphere, dew and rain with the help of velamen.
Q.14. Assertion: Pneumataphores are seen in Rhizophora.
Reason: From the region of elongation, some of the epidermal cells form root hairs.
AnswerAnswer: (c) The zone of elongation region of a root lies behind the growing point. The cells of this region are newly formed cells which lose the power of division. They elongate rapidly. This increases the length of the root. The root hair zone represents the zone of differentiation or maturation because of different types of primary tissues differentiates or matures in this region. Some of the outer cells of this zone give rise to lateral tubular outgrowths called root hairs.
Q.15. Assertion : Bud may form leaves and flowers.
Reason : Bud is a condensed shoot.