CBSE Questions for Class 11 Medical Biology Morphology Of Flowering Plants Quiz 2 - MCQExams.com

• A plant stem that grows horizontally under or along the ground and forms roots and shoots are called rhizomes. 
• The rhizome is the modification of the stem for the production of new plants.  For example, ginger, turmeric, and galangal.

• Thorns are modified branches or stems. Thorns are derived from shoots, they can be branched and they can have leaves. They arise from a bud. Thorns have vascular bundles inside. 
• Spines are derived from leaves and have vascular bundles inside. Spines are modified leaves, stipules, or parts of leaves, such as extensions of leaf veins. 
• Prickles are like coarse hairs. They are extensions of the cortex and epidermis. Prickles do not have vascular bundles inside, so they can be removed more easily.
• Bristles are an extension of a leaf vein that goes beyond the margin.

• The corm is a short underground storage organ of the plant. It is a swollen stem that stores food to survive winter, summer drought, and heat. It is also called a bulbotuber. It is covered with scale leaves or tunics. It is seen in plants like Amorphophallus, Colocasia, Corcus. 
• A corm consists of one or more internodes. Internally, a corm consists of parenchyma cells rich in starch. Corm, bulb, tuber, rhizomes are used for vegetative propagation.

Solution:

• Correct answer is option A.
• Explanation for correct option:
• The leaf is a flattened, lateral outgrowth of the stem in the branch, developing from a node and having a bud in its axil.
• Leaf refers to the organ that forms the main lateral appendage on the stem of vascular plants.
• The main function of a leaf is to carry out photosynthesis, which provides the plant with the food it needs to survive.

A) Correct option (C)
B) Explanation of the correct option

Option C: Corm: It is a condensed structure that grows vertically under the soil surface. They are having a spherical node and internode eg. Colocasia, Alocasia, Zaminkand, Saffron, Gladiolus, Colchicum

C) Explanation of incorrect option.

Option A):  Bulb is reduced and has a disc-like structure and surrounds with numerous fleshly scaly leaves. Many roots arise from its base. Food is stored in flashy leaves. 

Option B): Rhizome: It is fleshy and horizontally stems found below in soil. Small nodes and internodes are found which are covered by scaly leaves.

Option D): Bulbil is a tiny secondary bulb that forms between a leaf and stem or in place of flowers on certain plants.

• In spike, the central axis is elongated but flowers are sessile, e.g., Achyranthes. 
• In capitulum, the receptacle is flat, bears sessile small florets in a centripetal manner, e.g., Zinnia. 
• In dichasial cyme, peduncle bears two bracts at a node from which two branches arise, e.g., Dianthus. 
• In multiparous cyme, the peduncle bears a single terminal flower and below it, more than two lateral branches arise from a node, e.g., Asclepias. 
• In verticillaster, there is a condensed dichasial cyme type inflorescence, e.g., Coleus.

• Cyathium inflorescence is seen in Euphorbia splendens and Euphorbia pulcherrima (Poinsettia). 
• In cyathium inflorescence, the bracts become fused to form a cup-shaped structure. This cup completely encloses a single female flower surrounded by numerous male flowers. 
• The cyathium is surrounded by brightly coloured bracts.

• When fruit is formed from the entire inflorescence, like in pineapple, jackfruit, etc it is a composite fruit.
• Thalamus is the edible part of the apple.
• Gynobasic style is when style originates from the mid-basal part of the ovary, like in Ocimum.
• Cyathium is a special type of inflorescence found in Euphorbia species.

• Corymb (e.g., Cauliflower), catkin (Mulberry) and hypanthodium (Fig) are edible inflorescences. 
• In corymb, the main axis is short and all the flowers are more or less at the same level.
• In catkin, the spike inflorescence is pendulous with sessile flowers.
• In hypanthodium, the fleshy receptacle forms a hollow pear-shaped cavity. 

Solution

Correct answer is option A.

Explanation for correct option: