Problem 100 - Objective Biology for NEET

Question

Addition of what to auxins in nutrients medium causes proliferation of callus? (a) DNA (b) Yeast extract (c) Coconut milk (d) All of these

Step-by-Step Solution

Answer

The correct answer is (c) Coconut milk

Step 1: Understand the Terminology

Callus - In plant biology, callus refers to an unorganized mass of cells that are undifferentiated. This tissue can be induced to regenerate into whole plants, under the right conditions with specific plant hormones.

Step 2: Evaluating Options

Option (a), DNA, is not usually added to nutrient medium to cause proliferation of callus. It's involved in the plant's genetic makeup but isn't usually an added substance. Moving on to option (b), Yeast extract, it is typically used as a nutrient source in yeast cultures, and not accustomed for callus proliferation. Option (c), Coconut milk is commonly used in addition to auxins in growth medium to aid in callus proliferation due to it specifically contains substances that promote plant cell growth. Option (d) All of these is incorrect as DNA and yeast extract are not generally added to auxins for callus growth.

Step 3: Choose the Appropriate Answer

Based on the above examination of each option, it becomes clear that the correct answer is (c) Coconut milk.

Key Concepts

Callus Formation

Callus formation is a fascinating process in plant biology where an unorganized mass of cells called a callus is developed. These cells are undifferentiated, meaning they haven't decided what specific part of the plant they will become. Under the right conditions and with the correct mix of plant hormones, these cells can eventually develop into full plants.
This process is important because it allows scientists and farmers to clone plants and maintain desirable traits such as disease resistance or higher yield.

• Callus is often used in plant tissue culture techniques for propagation.
• These tissues can also be genetically manipulated to introduce new traits.

Understanding callus formation is key to advancing agricultural biotechnology and ensuring food security.

Auxins

Auxins are a class of plant hormones that play a crucial role in plant growth and development. They are responsible for stimulating cell elongation, which is essential for the growth of plant tissues. In the context of callus formation, auxins are particularly noteworthy.
They help in maintaining the right balance of plant hormones necessary for the callus cells to proliferate and eventually differentiate into various types of plant cells.

• High concentrations of auxins can lead to the formation of callus tissue.
• Auxins are essential for root development from stem cuttings.

The precise application of auxins in growth media is therefore pivotal when attempting to achieve successful callus formation.

Coconut Milk

Coconut milk plays a unique and essential role in plant tissue culture, particularly for callus proliferation. Containing various growth-promoting substances such as cytokinins and vitamins, coconut milk acts as an excellent natural supplement to auxins in the nutrient medium.
This combination fosters an ideal environment for the proliferation of callus, thereby enhancing the efficiency of the tissue culture process.

• Coconut milk provides organic compounds that are beneficial for plant tissue growth.
• It is often used in the tissue culture of orchids, where enhancing callus formation is crucial.

By incorporating coconut milk in the growth medium, researchers and horticulturists can optimize conditions to produce healthier, more robust plant tissues.