Question

Angular collenchyma occurs in:
(a)Datura
(b)Helianthus
(c)Cucurbita
(d)Both a and c

Answer 1

Hint: Collenchyma is the tissue found in plants whose cells are strengthened by the thickening around walls. The cells of these tissues are differentially thickened or the deposition may be restricted to the corner.

Complete answer:
Datura shows angular collenchyma i.e. thickening at the angles of the cells. There are four main types of collenchyma:
-Angular collenchyma: in this, the cells are thickened at intercellular contact points. Example: tomato and datura.
-Tangential collenchyma: in this, the cells arranged into ordered rows and thickened at the tangential face of the cell wall. Example: sunflower.
-Annular collenchyma: in this, the cells have uniformly thickened cell walls. Example: Nerium.
-Lacunar collenchyma: in this, the collenchyma is with intercellular spaces. Example: Cucurbita.
-The sclerified collenchyma is the mechanical support of mature plants.
-Collenchyma can aid as storage sites for defensive antimicrobial compounds. The compounds are rich in hydroxyproline bacterial agglutinins found in Solanum tuberosum.
So the correct answer is “Datura”.

Note: The functions of collenchyma are
-The cells are flexible with a significant degree of plasticity and so support the organs in which they occur.
-Chloroplast containing collenchyma can help in photosynthesis.
-In some cases, the bordering thick-walled collenchyma becomes thin and recovers the meristematic activity, e.g., phellogen, the cork cambium, which divides to produce the periderm.