Get premium membership and access questions with answers, video lessons as well as revision papers.

Describe the process of secondary thickening in a woody stem

      

Describe the process of secondary thickening in a woody stem

  

Answers


edwin
Facilitated by meristematic cells (cambium) located between the phloem and the xylem (intervascular cambium); it divides radially to form cambium tissues; with xylem forming the outer ring/to the inside; while the phloem forming the outer ring/to the outside; division of the cambium ring; form a secondary parenchyma; hence increases/forms the medullary rays; other xylems (secondary xylem) are formed; hence pushes the phloem and cambium ring outwards; this creates pressure on the outer cells; resulting in stretching and eventual rupturing of epidermal cells; a new band/volume of cambium cells are formed in the cortex beneath the epidermis (cork cambium cells/phellogen); to replace these ruptured cells; the phellogen cells divide on either side; where the inner cells become the secondary cortex; while those produced on the outside become cork cells; which are tightly packed; and become coated with an oily/waxy water-proof material/suberin; further multiplication of cork cells; lead to formation of the bark; which forms a protective layer (against water loss and damage by organisms); seasons results into annual rings; some cork cells form a loose mass/lenticels that allow gaseous exchange through the stem
Edwinnyongesa8 answered the question on December 4, 2018 at 03:37


Next: What is secondary growth
Previous: Discuss Lamarck’s and Darwin’s theories of evolution

View More Biology Questions and Answers | Return to Questions Index


Learn High School English on YouTube

Related Questions