Monocot Stem

Introduction

Monocotyledonous stems have lateral branches, the circular stem may exhibit depressed characteristics. The cuticle is thick, the epidermis is single-layered, and epidermal hairs are missing. Multicellular trichomes can be found in the single-layered cuticularized epidermis. The cortex and pith of the ground tissues are not separate. The sclerenchymatous hypodermis is frequent. Endodermis and pericycle are not present. Stomata and guard cells can be present in the epidermis. The sclerenchymatous bundle sheath cells that surround scattered vascular bundles are known as atactostele. Each vascular bundle is oval, linked, collateralized, and closed. The phrases pith and pith rays are synonymous. Endarch is xylem, and phloem is only represented by companion cells, sieve tubes, and little phloem fibers.

Anatomical Characteristics of Monocot Stem

• The epidermis is the uppermost uniseriate cuticularised layer of parenchyma with stomata. It is made up of barrel-shaped cells that are normally devoid of epidermal stem hairs
• The hypodermis is only found within the epidermis and is composed of densely packed sclerenchyma with no intercellular gaps. It offers mechanical strength to the plant
• Ground tissue is parenchymatous and does not differentiate into cortex, endodermis, pericycle, and pith as it does in dicots. These cells are smaller, polygonal, compactly arranged (toward the centre), or loosely arranged (toward the peripheral). The scatter vascular bundles are embedded in these tissues. These cells hold reserve resources
• Vascular bundles are conjoint, collateral, and closed. It comes in two sizes: larger and smaller, and it’s dispersed throughout the ground tissue with no rhyme or reason (atactostele). The larger vascular bundles are closer to the centre (fewer in number) and smaller towards the periphery (more in number). Each vascular bundle has an oval contour and is encircled by a sclerenchymatous bundle sheath that encloses Xylem and Phloem
• Xylem is made up of vessels, tracheids, xylem parenchyma, and restricted xylem fibres. The vessel is Y-shaped, with bigger two round pitted metaxylem vessels constituting the arms and smaller annual or spiral protoxylem vessels forming the base. The inner side of the protoxylem contains a big water cavity (schizolysigenous cavity, i.e. created by disintegration of some protoxylem). It holds water and is also known as a lacuna or a water cavity. The xylems are endarch, with exterior metaxylem and inner protoxylem
• In the vascular bundle, the phloem is located outside of the xylem. It is made up of sieve tubes, companion cells, and phloem fibers but lacks phloem parenchyma. The outer phloem is the protophloem, and the inner half is the functional metaphloem

Conclusion

Therefore, in this unit, we study about Monocot stem, its anatomical features, and its characteristics. We also learned about the difference between dicot and monocot stem. Monocot stem is the type of stem with two cotyledons present in its seed.  Examples of monocot stems are grass, maize, wheat, etc. Monocot stems vary in size, but they are rarely as large as dicot stems. It differs from dicot stems in various ways. These stems contain vascular-tissue bundles distributed throughout. In monocots, the vascular bundles are also found on the outside of the stem.