Question

Vascular strand having numerous scattered fibrovascular bundles is?
(a) Eustele
(b) Atactostele
(c) Polycyclic stele
(d) Dictyostele

Answer 1

Hint: Sclerenchymatous sheath-covered vascular bundles are contained in the monocot stem and they are called fibro vascular bundles. It is present in a form of eustele, in which the vascular bundles in a ground tissue are distributed or spirally arranged. In monocots, such as maize and rye, fibro vascular bundles are present.

Complete step by step answer:
Monocot stems, in which the stele consists of a complex arrangement of several vascular bundles, are said to have an atactostele. Atactostele is a stele with fibrovascular bundles distributed in arrangement. The outer vascular bundles of an atactostele are smaller than the inner vascular bundles.
A vascular bundle is an important part of the vascular plant transport system. Transportation itself occurs in vascular tissue, which has two forms: xylem and phloem. Both of these tissues are found in a vascular bundle that may include supporting and protective tissues in addition. Vascular bundles in the monocotyle leaf are covered by parenchymatous bundle sheath.
A stele with rings of vascular bundles is Eustele
A stele is called a siphonostele, with a central pith surrounded by vascular tissue. Such a condition is referred to as polycyclic and such steles are called polycyclic steles.
Dictyostele is a stele in which the entire stele, in the shape of a ring, is divided into smaller steles called meristeles.
So, the correct answer is, ‘Atactostele’.

Note: In the monocot stem, vascular bundles are covered by sclerenchymatous fibers. In the monocot root, there is no coating around the vascular bundles. In the dicot stem, there is no covering around the vascular bundles.