Question

Phloem parenchyma is absent in______
(a) Dicot leaf
(b) Monocot stem
(C) Dicot stem
(d) Dicot root

Answer 1

Phloem parenchyma is a type of cell found in the phloem which performs the function of transporting organic food in the plant body. It is absent in the plant body where no secondary growth occurs.

Complete answer:
Xylem and phloem are collectively known as vascular bundles. Xylem transport water and minerals from the roots to the entire plant body while phloem transports the organic food inside the body of the plant. Phloem parenchyma is a part of the complex tissue phloem. These are living and elongated parenchymatous cells that store food, resins, latex, etc. It has abundant plasmodesmata for the lateral conduction of food. Phloem parenchyma is absent in most of the monocots. Thus, the monocot stem is the one among the options that do not contain phloem parenchyma.

Additional Information: The other parts of phloem include:
Sieve tubes: A sieve tube is made of shorter segments or cells called sieve tube elements or members. They are placed end to end. The end walls contain sieve pits and it is the reason it is also known as sieve plate. Also, the sieve member is enucleated.
Companion cells: They are narrow, elongated, thin-walled living cells which lie beside the sieve tubes. Their close companionship is maintained by plasmodesmata. Its nuclei control the activities of sieve cells also.
Phloem or Bast Fibres: They are absent in primary phloem but abundant in secondary phloem. They provide mechanical strength and occur in sheets or cylinders. The fibers of jute and hemp are phloem fibers.
So, the correct answer is ‘(b) Monocot stem.’

Note: Xylem and phloem are an example of complex permanent tissues. These tissues are named so because they are made up of more than one type of cell and all these different types of cells coordinate to perform the same function. They ultimately achieve the same goal despite their different structures and function.