Question

The most primitive type of stele is
A. Eustyle
B. Solenstele
C. Protostele
D. Siphonostele

Answer 1

Hint: A column containing vascular tissues (xylem and phloem) surrounded by pericycle is called stele. Stele is surrounded by pericycle and it is separated from ground tissue by means of endodermis.

Complete Answer:
The most primitive type of stele is protostele. The stele is a column of tissue that consists of vascular tissues and ground tissues. The vascular tissues are the conducting tissues that help in the transportation and conduction of materials along the plant. These vascular tissues are also called conducting tissues and they provide mechanical support to plants.
Stele turns are used for stem and roots to describe vascular state.
(a) Protostele: Protostele is the most primitive type of stele. When present in stem, it has no gaps. They form the core of xylem. Example: Haplostele, Actinostele and plectostele

(b) Siphonostele: These are hollow cylinders of xylem and have leaf gaps present in its structure. It shows pith in its structure. These steles are common in stem of ferns.
Siphonostele are of two types:
(1) Solenostele: It is the simplest type of siphons tale that has few gaps. It can form one to several leaves at a time.
(2) Dictyostele: This type of stele highly dissected siphonostele. These steles have gaps in their structure because they form several leaves at one time.

(c) Eustele: In eustele no true leaf gaps are presented. They show the presence of pith. The xylem and phloem are arranged in the form of a vascular ring.

Therefore, from the above explanation the correct option is (C) Protostele.

Note: Vascular bundles are conducting tissue. They are of two types xylem and phloem, xylem functions in transportation of water and minerals and phloem functions in transportation of food material.