Write Dicotyledonous and Monocotyledonous Stem.

Question: 

Write Dicotyledonous and Monocotyledonous Stem.

Answer

Dicot Stem

The dicotyledonous stem is usually solid. The transverse section of a typical young dicotyledonous stem consists of the following parts:

• The epidermis is the outermost protective layer, which is covered with a thin layer of cuticle.
• Epidermis possesses trichomes and a few stomata.
• Cortex is multi-layered cells sandwiched between epidermis and pericycle.
• The outer layer, hypodermis (collenchymatous cells), the cortical layers (parenchymatous cells) and the inner layer, endodermis together make up the three subzones of the cortex.
• Next to endodermis is the pericycle, which is constituted of semi-lunar patches of sclerenchyma.
• ‘Circled’/ ‘ring’ arrangement of vascular bundles is present only in dicot stem.
• The Vascular bundle is conjoint, open and with endarch protoxylem.
• Pith is evident and is made of parenchymatous cells.

Monocot Stem

Monocot stem is usually hollow with no secondary growth. The anatomy of monocot and dicot stem are similar, however, some notable differences are as follows:

• The hypodermis of the cortex in monocots is made of sclerenchymatous cells.
• Vascular bundles are numerous, but scattered, conjoint and closed, surrounded by the ground tissue.
• Phloem parenchyma is absent.