Question

describe the TS of a dicot stem like 8 marks question​

Answer 1

ANATOMY OF DICOT STEM - DEFINITION

concept

The Dicot Stem contains vascular bundles arranged in a ring around the pith. Vascular bundle is conjoint, collateral, open and endarch. Stem contains two cotyledon or embryonic leaf called as dicotyledonous stem or dicot stems.

1. Epidermis

It is a protective outermost single layer of parenchymatous cells without intercellular spaces.

The outer walls of the epidermal cells have a layer called cuticle and multicellular hairs (trichomes).

2. Cortex

Below the epidermis, cortex is differentiated into few layers of collenchyma cells that make hypodermis which gives mechanical strength to the stem.

A few layers of chlorenchyma cells are present with conspicuous intercellular spaces. Some resin ducts also occur here.

The third zone is made up of parenchyma cells. These cells store food materials.

3. Endodermis: (Starch sheath)

The cells of this layer are barrel shaped arranged compactly without intercellular spaces.

Due to abundant starch grains in these cells, this layer is also known as starch sheath.

3. Stele

It consists of pericycle, vascular bundles and pith.

A) Pericycle (Bundle cap)

Pericycle occurs between the endodermis and vascular bundles in the form of a few layers of sclerenchyma cells.

B) Vascular bundles

In dicot stem, vascular bundles are arranged in a ring around the pith.

Each vascular bundle is conjoint, collateral, open and endarch.

C) Pith

The large central portion called pith composed of parenchyma cells with intercellular spaces.

The extension of pith between vascular bundles are called as pith ray or medullary rays.

Function of the pith is storage of food.

I even have attached a picture.

Hope it's helpful...

Answer 2

The TS of a dicot stem is conjoint, collateral, endarch and has open vascular bundles.

Anatomy of TS of dicot stem

• Epidermis: It is a single layer of parenchymatous cells that protects the outermost layer of the body and has no intercellular gaps.
• Cortex: Cortex differentiates into a few layers of collenchyma cells beneath the epidermis, forming the hypodermis, which provides mechanical strength to the stem.
• Endodermis: This layer's cells are barrel-shaped and tightly packed, with no intercellular gaps. This layer is also known as the starch sheath because of the abundance of starch granules in these cells.
• Pericycle: Pericycle occurs in the form of a few layers of sclerenchyma cells between the endodermis and vascular bundles.
• Medullary rays: The spaces between the vascular bundles are where the medullary rays are found. This void is filled with thin-walled parenchymatous cells distributed radially in a few rows. It aids in the storage of food and the lateral transport of water and food.
• Vascular Bundles: The pith is surrounded by a ring of vascular bundles which could be conjoint, collateral and open.
• Pith: The pith is a big centre section made up of parenchyma cells with intercellular gaps. The pith's purpose is to store food.