Growth rings are formed due to the activity of
As we know that Intrafascicular or intrastelar cambium is present between xylem and phloem in dicot stem and roots. Pith rays, present between the edges of intrafascicular cambium, divide to form a new cambium strip between the two vascular bundle i.e. interfascicular cambium. Thus, inter and intra fascicular cambium together forms a complete cambium ring called as vascular cambium or just cambium which forms secondary xylem on inner side and secondary phloem on outer side. Differential cambial activity during autumn and spring season result in narrow and wide secondary xylem rings respectively which together forms the annual growth ring. Thus annual growth ring is derived from vascular cambium which is derived from inter and intrastelar cambium.
A cambium is lateral meristem, not intercalary. The extra stelar cambium, present outside the stele region is termed as cork cambium or phellogen. It is derived from pericycle (a primary permanent tissue) and produces cork or phellem towards the periphery and phelloderm or secondary cortex on inside, they are the extra stelar secondary tissues and are not part of annual growth rings.
Primary cambium or procambium is the embryonic tissues that give rise to primary vascular bundle; annual growth rings are formed by secondary vascular bundles.
Therefore, the correct answer is option A.
Read the different components from (a) to (d) in the list given below and tell the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem. (a) Secondary cortex (b) Wood (c) Secondary phloem (d) Phellem
Cut a transverse section of young stem of a plant from your school garden and observe it under the microscope. How would you ascertain whether it is a monocot stem or a dicot stem? Give reasons.
What is a periderm? How does periderm formation take place in the dicot stems?
Hypodermis is _______ in sunflower stem and _________ in maize stem.
In a mature dicot stem. which has undergone secondary growth, the youngest layer of secondary xylem is situated
Read the following statements and select the correct option. Statement 1: Annual rings are distinct in plants growing in temperate regions Statement 2: In temperate regions, the climatic conditions are not uniform through the year
Which of the following statements is incorrect?
Select the correct option: Given are a few peculiar parts/structures found in plants Cucurbita stem, potato tuber, walnut shell, jute fibres. Identify the tissue responsible for the distinguishing feature in each part respectively and select the correct option
A conjoint and open vascular bundle will be observed in the transverse section of
Pith is not well developed in