Problem 126 - Objective Biology for NEET

Question

Initially formed cambium in dicot root is (a) Circular (b) Rectangular (c) Oval (d) Wavy

Step-by-Step Solution

Answer

The initial formation of cambium in a dicot root is (a) Circular.

Step 1: Recall the concept of Cambium in Dicot Root

Cambium in dicot root refers to the layer of cells in plants that separates the xylem and phloem and contributes to secondary growth making the plant thicker over time. The initial shape of cambium in dicot root is significant in understanding its function.

Step 2: Identify the Initial Structure

Based on botanical studies, initially formed cambium in a dicot root is circular in shape. Hence, the choice is (a) Circular.

Key Concepts

Secondary Growth

Secondary growth refers to the process that helps plants increase in thickness or girth. This growth is an essential function for woody plants as it allows them to support larger structures and to transport water and nutrients effectively. Secondary growth mainly occurs in the stem and root of dicotyledons, commonly known as dicot roots.

During secondary growth, a plant forms secondary vascular tissues like secondary xylem (wood) and secondary phloem. This process essentially thickens the existing layers. The cambium, which is a lateral meristem located between xylem and phloem, facilitates this growth.

• The formation of new cells from the cambium enhances the diameter of roots and stems.
• Secondary growth is crucial for the longevity and stability of trees and shrubs.

Ultimately, secondary growth is vital for a plant's survival and adaptation, allowing the plant to sustain taller and more complex above-ground structures.

Xylem and Phloem

Xylem and phloem are the two main types of transport tissues in vascular plants, each serving a distinct purpose.

Xylem is responsible for transporting water and dissolved minerals from the soil upward through the plant to the stems and leaves. This process is crucial for photosynthesis and overall plant health. Newly formed xylem tissue from the cambium is added annually, contributing to the plant’s secondary growth.

• Xylem helps form the woody component of the tree.
• It also supports the plant structurally.

In contrast, phloem is responsible for transporting nutrients, primarily sugars, throughout the plant. These nutrients are produced in the leaves during photosynthesis and are essential for plant growth and development. Like xylem, the cambium adds new layers of phloem each year, allowing the plant to expand.

• Phloem distribution is crucial for feeding all parts of the plant.
• Protection of phloem helps prevent starvation of plant tissues.

Together, xylem and phloem facilitate both growth and nutrient distribution, ensuring the plant thrives and remains healthy.

Plant Anatomy

Plant anatomy is the study of the internal structure of plants. It is key to understanding how plants function, grow, and survive. Focusing on components like tissues and cells, plant anatomy reveals how plants perform various life-sustaining functions.

A fundamental component in plant anatomy is the vascular system, comprised of xylem and phloem.

• The vascular system allows the distribution of water, minerals, and nutrients throughout the plant.
• It also provides structural support and aids in growth.

Another crucial element in plant anatomy is the cambium, a layer of actively dividing cells. Situated between the xylem and phloem, the cambium is pivotal for secondary growth.

• Cambium activity leads to the thickening of stems and roots.
• It also plays a role in healing and repairing plant tissues.

Understanding plant anatomy, including all its tissues and functions, demystifies how plants maintain growth and resilience, efficiently interacting with their environment.