Question

Periderm is formed from
(a) Vascular cambium
(b) Phellogen
(c) Fascicular cambium
(d) Interfascicular cambium

Answer 1

Hint: It refers to the collective term wanting to signify phellogen, phellem, and phelloderm during a plant stem. It's formed in plants, mainly occurring to exchange the prevailing epidermis. It's composed of thin-walled, narrow, and rectangular cells.

Complete answer:
A. Vascular cambium – produces secondary vascular tissues and ray parenchyma.
B. Fascicular cambium – a strip of cambium present between the xylem and phloem of a vascular strand is named fascicular cambium. It involves secondary growth.
C. Phellogen – a hoop of cambium formed within the cortex of dicot stem, by the dedifferentiation of parenchyma is named Phellogen. it's involved within the formation of the periderm.
D. Intrafascicular cambium - a strip of cambium present between the xylem and phloem of a vascular strand is named fascicular cambium. It involves secondary growth.

Additional information: The formation of periderm occurs during secondary growth. During this process, to exchange the broken outer epidermal layer and therefore the cortical layer, the cells of the cortex turn meristematic.

Thus, cork cambium or phellogen is made. The phellogen comprises slightly walled, restricted, and rectangular cells. Later on, the phellogen cuts off cells on either side. The cells of the external side produce the phellem or plug which because of the statement of suberin in its cell layer is impenetrable to water. Additionally, the inward side structures the optional cortex or phelloderm which is particularly parenchymatous in nature.
So the correct answer is ‘Phellogen’.

Note: Analysis of mature tuber periderm, however, might not produce easily identifiable phellogen or phelloderm. A study of all three periderm cell types in immature and mature periderm was needed to work out maturational changes. Recently have these periderm cell structures been plainly shown for simpler identification and related morphological depiction. The suberization measures engaged with phellem improvement are just halfway described.