Question

Vegetative Propagation in Cycas occurs by
A. Scale leaves
B. Sporophylls
C. Bulbils
D. Fragmentation

Answer 1

Hint: Vegetative reproduction is also called as vegetative propagation, vegetative multiplication or cloning. It is a kind of asexual reproduction that occurs in plants where a new plant grows from a part of the parent plant or specialised reproductive structures; root, stem and leaves.

Complete answer: Vegetative reproduction in Cycas occurs by bulbils. Bulbils (cresting adventitious buds) are produced on the stem in the axil of scale leaves. Bulbils are protected by scale leaves. During favourable conditions, bulbils detach itself from the parent plant and grow into an independent sporophyte. These young plants are generally the clone of the parent plant and have identical genetic material with the parent. Bulbils are the airy propagating structures of Dioscorea that appear on the axil of a leaf or bract, which shows diversity in size and shape. The bulbil is the same as that of the tuberous underground stem in having cork, cork cambium and parenchyma ground tissue with distributed vascular bundles. The bulbil develops as a composite structure especially due to diffused growth of more than one accessory bud which arises on the abaxial side of the axillary bud. Though some bulbs meet the botanical criteria to be considered a true bulb, there are a variety of different morphological forms of bulbils, out of some of them are not considered as bulbs. For example, some bulbous plant groups, like onions and lilies, produce bulbils in the form of a secondary, small bulb. Onion and lily bulbils meet the botanical criteria to be called a true bulb. All bulbils that are produced by bulbous plants are considered to be bulbs, but not all bulbils are to be considered bulbs.
Hence, the correct answer is option C.

Note: Another non-bulbous plant groups, various genera within the subfamily Agavoideae are generally known as to produce bulbils that actually do not meet the botanical criteria as to be considered a bulb.