Question

In which stem the scattered vascular bundles are found?

Answer 1

Hint: Scattered vascular bundles are advanced characteristics in the evolutionary line. Vascular bundles are made up of conducting tissue called xylem and phloem.

Complete step by step solution:
The stem of a monocot plant possesses scattered vascular bundles and lacks a distinct pith. The vascular bundles are arranged in a centrifugal pattern, i.e., the older ones lie towards the center whereas the new bundles are arranged towards the periphery. Younger bundles are smaller in diameter when compared to older ones. Each bundle contains xylem and phloem surrounded by a layer of sclerenchyma


Additinal Information:
The theory of evolution of stele suggests that the scattered vascular bundle is an evolutionarily advanced characteristic. The monocots are more evolved than the dicots and have scattered vascular bundles. Such vascular bundles are said to be closed because they lack cambium and do not produce any secondary xylem or phloem. On the other hand, dicot stems have open vascular bundles arranged in rings. They have cambium and produce secondary conductive tissues.

Note: Vascular bundles contain xylem and phloem. Xylem and phloem are conducting tissue of plants. Xylem conducts water and minerals from roots to other parts of the plant whereas phloem is responsible for conducting food from leaves to different parts of the plant. The cambium is a type of actively dividing tissue. It can be cork cambium or vascular cambium. The one which gives rise to the xylem and phloem and plays a role in the lateral growth of the plant is called the vascular cambium.