Question

Meristems are found in
A. Cycas stem
B. Pinus needle
C. Fern leaf
D. Fern rhizome

Answer 1

Hint: A meristele is an amphiphloic siphonostele. It is mainly present in vascular plants of the class Polypodiopsida. This plant first appeared in the fossil record about 360 million years ago in the middle Devonian period.

Complete answer: Meristeles are one of the totals of the vascular tissue in a polystele. Moreover, the meristele is a strand of the vascular tissue which is embedded in case of the endodermis and makes a portion of the dictyostele. The siphonosteles are of different types. The gaps present in the leaf which are overlapping in the siphonostele are called the dictyostele. Inside the leaf gaps, tissues are present. The meristele is the vascular tissues found inside the gaps. These types of meristeles are seen in the rhizomes of the fern. Out of all the living plants, this type of stele is found only in the stems of ferns.
i. Cycas stem: It is a perennial and slowly growing evergreen plant also referred to as the living fossil since it occurs as a fossil, for example, C. fusiana. It looks like a palm tree. Its main plant body is sporophytic, diploid and dominant and can also be differentiated into three parts like roots, stem and leaves.
ii. Pinus needle: The needle of the pines are arranged in a spiral around the stem. Every year as the branch of a pine tree grows; it produces a whorl of new leaves which is called the candle.
iii. Fern leaf: The leaves of the ferns are frequently known as fronds. The fronds are usually composed of a leafy blade and the petiole.
iv. Fern rhizome: The stem of a fern is referred to as the rhizome. The rhizome develops horizontally beneath the surface of the soil. Some of the rhizomes elevate closer to the surface level of the ground at the tip.
Therefore, the correct answer is option D.

Note: The fern is a member of a group of the vascular plants, i.e. these plants have xylem and phloem and reproduce through spores. They have neither seeds nor the flowers. The ferns are unique in land plants in having two separate living structures, hence, the fern plant that we see out in the bush produces spores.