Question

The meristem that occurs in the mature regions of roots and shoots of many plants, particularly those that produce woody axis and appear later than primary meristem, is called (a) Intercalary meristem (b) Apical meristem (c) Secondary or lateral meristem (d) All the above

Short answer

The correct answer is (c) Secondary or lateral meristem.

Step-by-step solution

Understand the different types of meristems

Apical meristems are found at the tips of roots and shoots, and they are responsible for the primary growth (lengthening) of the plant. Intercalary meristems are found at the base of leaves or internodes, contributing to the elongation of the stem. Secondary or lateral meristems are responsible for the secondary growth (widening) of the plant and are typically found in woody plants.

Identify the meristem described in the question

The problem states that this type of meristem occurs in mature regions of roots and shoots, particularly in woody plants, and appears later than the primary meristem. This aligns more with the description of secondary or lateral meristem.

Select the correct option

Based on our understanding, the most fitting option that describes the meristem in the question is secondary or lateral meristem.

Key concepts

Apical Meristem

Apical meristems are essential components of plant growth and development, marking the regions where plants grow in height and root length. These meristems are located at the very tips or "apexes" of the plant, such as the root tips and shoot tips. They play a crucial role in a plant's primary growth by actively dividing to add cells that elongate stems and roots.

The activity in the apical meristem is crucial for plants to reach new sources of light and nutrients, a process vital for survival. In addition to contributing to the elongation, the apical meristem also participates in forming leaves and flowers by providing new cells.

Plants rely on the apical meristem for ongoing growth throughout their lifecycle. This capability grants them the plasticity to adapt to environmental changes, expanding their access to resources over time. Understanding the function of apical meristems illuminates how plants can sustain growth and develop intricate structures necessary for their survival and reproduction.

Intercalary Meristem

The intercalary meristem is another type of plant tissue that contributes significantly to how plants grow, but it functions differently from the apical meristem. Found at the bases of leaves and internodes—the sections between the places where leaves attach to the stem—this meristematic tissue is primarily responsible for the elongation of these areas.

Unlike apical meristems, intercalary meristems allow plants, such as grasses and bamboos, to rapidly regrow leaves and stems from the base. This type of growth is particularly important for plants that frequently experience grazing or require rapid recovery from damage.

The active division of cells in the intercalary meristem permits parts of the plant to extend, offering a strategic advantage. This type of growth is vital for the regeneration of plant parts, ensuring new growth even after parts of the plant have been eaten or cut. Thus, it plays a pivotal role in the resilience and vitality of many plant species.

Plant Growth

Plant growth is a dynamic process involving various types of meristematic tissues that contribute to a plant's structural development and adaptation to its environment. In essence, plant growth can be divided into primary and secondary growth.

**Primary Growth:** This type of growth involves courtesy of the apical meristems, contributing to height and length. This provides the plant with the ability to reach toward resources like light for photosynthesis and penetrate deeper into the soil for nutrients and water.

**Secondary Growth:** Conducted by secondary or lateral meristems, such as the vascular cambium and cork cambium, this growth is vital for the thickening of plant tissues, particularly in woody plants. It allows trees and shrubs to expand their girth, providing support to the plant and accommodating increased vascular flow to sustain larger leaf and root mass.

Overall, the fine-tuned coordination between apical, intercalary, and secondary meristems facilitates both extensive and intensive plant growth, empowering the plant to thrive and adapt in its habitat. Understanding these processes is key to comprehending how plants develop intricate systems to maintain life and reproduce effectively.