Question

Which one of the following has the bast fibers
a. Parenchyma
b. Sclerenchyma
c. Phloem
d. Xylem

Answer 1

Hint: Bast fibers are found in the stems of the dicotyledonous plants. Bast fibers are part of vascular tissue. They run across the full length of the stem and are very long. Examples of these are jute, rattan, industrial hemp, flax, and vine fibers.

Complete answer:
- The term “bast” derives from the word baest which means the inner bark of trees from which ropes are made.
- Bast fibers are the plant fibers which are collected from the phloem (inner bark) or are obtained from the skin or bast surrounding the stem of dicotyledonous plants.
- Bast fibers support the conductive cells of the phloem and it also provides strength to the stem.
- Whereas, parenchyma consists of living cells which are thin-walled and unspecialized in structure. Their functions are such as photosynthesis, gas exchange, sap secretion, and food storage.
- Sclerenchyma tissue makes the plant hard and stiff and their cell walls are formed of cellulose, hemicellulose, and lignin.
- Xylem is a vascular tissue that transports water and dissolved substances from the roots to the other parts of the plant. It also provides support to the plant.

Hence, the correct answer is option (C).

Additional information:
Phloem is the vascular tissue that is responsible for the translocation of sugar from source tissues to the sink tissues. Economically important bast fibers are collected from the herbs which are cultivated in agriculture, for instance, hemp, flax. Bast fibers are used in yarn, rope, carpet, packaging, and paper.

Note: Bast fiber is collected from the phloem or from the bast that surrounds the stem of certain dicotyledonous plants. Bast fibers provide support to the connective cells of the phloem and also strengthens the stem.
Phloem fibers are also known as bast fibers because they are present in inner bark or in the bast which is surrounding the stem of certain dicotyledonous plants.