Problem 8 - Objective Biology for NEET

Question

Which tissue occurs in grasses and regenerate parts removed by the grazing herbivores? (a) Apical meristem (b) Lateral meristem (c) Intercalary meristem (d) All of these

Step-by-Step Solution

Answer

The tissue that occurs in grasses and can regenerate parts removed by grazing herbivores is the (c) Intercalary meristem.

Step 1: Understanding the function of the meristems

Plant tissues are divided into meristems (active tissues that cause growth) and permanent tissues. There are three types of meristems: Apical meristem (located at the tips of stems and roots), Lateral meristem (allows plants to grow in diameter or thickness), and Intercalary meristem (located at the base of leaves or internodes, primarily responsible for elongation).

Step 2: Identifying which meristem can regenerate tissues

Considering that the question asked about the regeneration of parts removed by grazing herbivores, the focus is on the meristem found at the base where regrowth can quickly occur without starting from the tip. Environmental adaptation of grasses allows them to regrow effectively after being grazed - this places an emphasis on Intercalary meristem.

Step 3: Making the selection

Considering the information in previous steps, it can be concluded that the tissue which occurs in grasses that regenerates parts removed by grazing herbivores is the Intercalary meristem. So, the correct answer is (c) Intercalary meristem.

Key Concepts

Intercalary Meristem

Intercalary meristem is a special type of growth tissue predominantly found in the grasses. This meristem is located at the base of leaves or just above the nodes of grass plants. Its unique position allows grasses to quickly regrow parts that are removed during grazing by herbivores. The presence of intercalary meristem is why grasses can be routinely cut or eaten and still continue to grow without much disturbance.

• The primary function of intercalary meristem is to facilitate regrowth and elongate the stem.
• It plays a pivotal role in the adaptation of grasses to environments where grazing is common.

Unlike other plants that rely on growth from the tip, grasses can regrow from these centralized growth points. This advantage ensures that leaves and stems can rapidly regenerate, making grasses resilient and adaptive to regular cuttings. This ability contributes significantly to the overall longevity and survival of grass species in diverse ecosystems.

Apical Meristem

The apical meristem is found at the tips of roots and shoots in plants, playing a crucial role in primary growth. This type of meristem is where cells continuously divide, pushing the root or shoot to grow longer. As a result, the plant can expand its reach – roots delve deeper into the soil, while shoots stretch further towards sunlight.

• Apical meristems are the reason plants can grow upwards and downwards effectively.
• This growth process is vital for ensuring that a plant can access water, nutrients, and light resources.

While apical meristems are integral to initial plant growth, they are not the primary tissue responsible for regeneration of grazed areas in grasses. They are more about extending the length and height of the plant rather than aiding in regrowing eaten parts. Still, their role is indispensable in a plant's developmental framework.

Lateral Meristem

Lateral meristems differ from other types of meristematic tissues as they are responsible for the plant's growth in thickness. Found in woody and some herbaceous plants, these meristems allow for secondary growth, which is crucial as the plant matures and requires additional support. The most well-known lateral meristems are the vascular cambium and the cork cambium.

• Vascular cambium contributes to the thickening of stems and roots by producing new layers of vascular tissues.
• Cork cambium forms the outer protective layer of bark.

In grasses, lateral meristems do not play a significant role in regeneration after grazing. Their primary function is expanding plant girth, making them essential in the life cycle of many trees and shrubs. However, they do not contribute to the quick replacement of lost tissues like intercalary meristems do in response to grazing.