Problem 161 - Objective Biology for NEET

Question

The polyarch condition is seen in (a) Monocot stem (b) Monocot root (c) Dicot root (d) Dicot stem

Step-by-Step Solution

Answer

The polyarch condition is seen in Monocot root.

Step 1: Understand the key terms

Polyarch condition refers to a condition where the central vascular cylinder of a root has more than six xylem poles. In other words, it's where more than six primary xylem bundles are observed. It's generally seen in the roots of certain plants.

Step 2: Refer to plant anatomy knowledge

Monocot and dicot plants differ in their anatomy. In general, monocots have a polyarch xylem in the root, whereas dicots have a tetrarch or pentarch xylem.

Step 3: Match with the choices

Given this knowledge, the polyarch condition will likely be seen in the root of a monocot.

Key Concepts

Polyarch Condition

The polyarch condition is a fascinating aspect of plant anatomy often observed in roots. In this condition, the vascular cylinder of the root features multiple xylem poles—specifically, more than six. These are known as polyarch xylem arrangements. This kind of xylem configuration is characteristic of monocot roots, providing a significant distinction from dicot roots.

• Polyarch condition = more than six xylem bundles.
• Typically found in monocot roots.
• Helps identify plant types in studies.

Understanding where and why this condition occurs provides insights into plant adaptation and structure differences among various plant types.

Monocot Root

Monocot roots are one of the primary types observed in plant anatomy, distinguishing themselves by their unique internal structure. Unlike dicots, monocots display a polyarch condition in their roots. This means there are several xylem bundles converging in the centre of the root.

• Monocot roots = polyarch xylem (many xylem poles).
• Aid in identifying monocot plants among others.

The structure helps in the efficient transport of water and nutrients along with providing support to the plant. Learning about monocot roots is essential in understanding overall plant biology and functionality.

Vascular Cylinder

The vascular cylinder is essential to understanding plant physiology. It resides in the center of a plant's root and is made up of different tissues, including xylem and phloem, which are crucial for transportation inside the plant.

• Central part of plant roots.
• Composed mainly of xylem and phloem.

In a polyarch condition, the vascular cylinder includes multiple xylem bundles, which make nutrient and water transport more efficient in monocot roots. This component plays a significant role in plant growth and nutrition.

Xylem Bundles

Xylem bundles are integral in the transportation system of plants, part of the vascular tissues responsible for carrying water and nutrients from the roots throughout the plant. In a polyarch condition, more than six xylem bundles converge within a plant root.

• Major component: transportation of water/nutrients.
• Look for multiple bundles in polyarch roots.

This arrangement can enhance the ability of the root to transport necessary resources, characteristic of monocot roots. Understanding xylem bundles equips us with knowledge about plant efficiency and adaptation.