Question
Question: Which of the following is made up of dead cells? A) Phloem B) Xylem parenchyma C) Collenchyma ...
Which of the following is made up of dead cells?
A) Phloem
B) Xylem parenchyma
C) Collenchyma
D) Phellem
Solution
-The word tissue is derived from the French word “tisse” which means “ to weave”. tissue is defined as organisation of similar types of cells together that also carry out similar functions. Both animals and plants are made up of tissues but their type and functions are different.
Complete answer:
Plant tissues are broadly categorised into two types- meristematic tissue and permanent tissue. Meristematic tissue are those which are in their actively dividing state. It helps in the primary growth of the plant by causing increase in length and thickness.
Permanent tissues are those that have lost the ability to divide and are committed towards performing a specialized function. They are subdivided into simple and complex permanent tissue. Simple permanent tissues are of three types- parenchyma, collenchyma and sclerenchyma.
Parenchyma is a living tissue and helps in providing support and storing food, collenchyma is also a living tissue that provides tensile strength to plants and sclerenchyma comprises dead cells and provides mechanical support to the plants.
Complex permanent tissue comprises xylem and phloem which form the vascular bundle of plants. Xylem consists of tracheids, vessels , xylem sclerenchyma and xylem parenchyma which together help in the transport of water and mineral salt to different parts of the plant.
Phloem consists of sieve tube, companion cell, phloem fibre or phloem parenchyma all of which help to transport dissolved food material to different parts of the plant. Phellem in turn is a part of cork cambium that is made up of dead cells and helps to provide protection at the outer surface.
Hence the correct answer is option (D) Phellem.
Note: Most of the different plant tissues are made of living cells that help in growth and development of the plant but few tissues that are made up of dead cells provide mechanical support that helps the plants to survive adverse conditions.