What is Ethylene (Plant Hormone)?

S6-SA5-0119

Grade Level:

Class 10

AI/ML, Physics, Biotechnology, Space Technology, Chemistry, Engineering, Medicine

Definition

What is it?

Ethylene is a simple gaseous plant hormone that plays a crucial role in plant growth and development. It is primarily known for its involvement in fruit ripening and the aging (senescence) of plant parts.

Simple Example

Quick Example

Imagine you buy raw mangoes from the market to make aamras. If you keep them in a paper bag with a ripe banana, they ripen much faster. This happens because the ripe banana releases ethylene, which tells the raw mangoes to ripen quickly too.

Worked Example

Step-by-Step

Let's say you have 10 raw tomatoes. You want to ripen them quickly for a salad.
---STEP 1: Identify the ripening agent. Ethylene is the natural ripening hormone.
---STEP 2: Find a source of ethylene. Ripe fruits like bananas or apples naturally produce ethylene.
---STEP 3: Place the raw tomatoes in a sealed container (like a paper bag or a closed box) along with 1-2 ripe bananas.
---STEP 4: The ethylene gas released by the bananas will accumulate in the container.
---STEP 5: This concentrated ethylene gas will signal the raw tomatoes to speed up their ripening process.
---STEP 6: After 1-2 days, you will notice the tomatoes have started to turn red and soften, ready for your salad.
ANSWER: The tomatoes ripened faster due to the ethylene gas from the bananas.

Why It Matters

Understanding ethylene is vital in Biotechnology for improving crop shelf-life and in Agriculture for managing fruit ripening. It helps scientists develop new ways to store fruits longer or ripen them on demand, impacting food security and reducing waste globally.

Common Mistakes

MISTAKE: Thinking ethylene only helps fruits ripen. | CORRECTION: While fruit ripening is a key function, ethylene also plays roles in flower senescence (aging), leaf abscission (falling off), and responses to stress.

MISTAKE: Confusing ethylene with other plant hormones like auxins or gibberellins. | CORRECTION: Ethylene is unique because it's a gaseous hormone, unlike auxins, gibberellins, cytokinins, and abscisic acid, which are non-gaseous.

MISTAKE: Believing all fruits ripen with external ethylene. | CORRECTION: Climacteric fruits (like bananas, mangoes, apples) ripen significantly in response to ethylene, but non-climacteric fruits (like grapes, oranges, strawberries) do not ripen further once picked, even with ethylene.

Practice Questions

Try It Yourself

QUESTION: Which gas is primarily responsible for fruit ripening? | ANSWER: Ethylene

QUESTION: A farmer wants to delay the ripening of his apples during transport. What hormone's effect should he try to reduce? | ANSWER: Ethylene

QUESTION: Why is it advised not to store ripe bananas with fresh vegetables like cucumbers or carrots in the same sealed bag? | ANSWER: Ripe bananas release ethylene, which can cause fresh vegetables to age and spoil faster.

MCQ

Quick Quiz

Which of the following is a gaseous plant hormone?

Auxin

Gibberellin

Ethylene

Cytokinin

The Correct Answer Is:

Ethylene is the only plant hormone listed that exists in a gaseous form and is known for its role in fruit ripening. Auxin, gibberellin, and cytokinin are non-gaseous hormones.

Real World Connection

In the Real World

In India, cold storage facilities and mandis (wholesale markets) often use controlled environments to manage ethylene levels. For example, some facilities remove ethylene gas to keep fruits and vegetables fresh for longer, while others might introduce it to ripen fruits like bananas and mangoes on demand for festivals or peak season sales.

Key Vocabulary

Key Terms

HORMONE: A chemical substance produced in the body that controls specific processes | RIPENING: The process by which fruit becomes ready to eat | SENESCENCE: The biological process of aging and deterioration | CLIMACTERIC FRUIT: Fruits that continue to ripen after being harvested, often due to ethylene | ABSCISSION: The natural detachment of parts of a plant, typically leaves and ripe fruit

What's Next

What to Learn Next

Now that you understand ethylene, explore other plant hormones like auxins and gibberellins. You'll see how these different chemical messengers work together in a plant to control its entire life cycle, from tiny seeds to towering trees!