In plant physiology, the growth hormone gibberellin was first discovered in which country while studying the “foolish seedling” disease in rice?

Introduction / Context:
Gibberellins are important plant hormones that promote stem elongation, seed germination, and other growth processes. Their discovery is a classic story in plant physiology and agricultural science. This question asks you to recall the country in which gibberellin was first discovered, in connection with a peculiar rice disease that caused abnormal overgrowth of seedlings. Knowing this helps you connect basic biology with historical research in crop science.

Given Data / Assumptions:

• The question is about the plant hormone gibberellin.
• It was discovered while studying “foolish seedling” disease in rice plants.
• We must identify the country of discovery, not the individual scientist.
• The options are major countries including India, Japan, China, and Russia.

Concept / Approach:
The disease called “bakanae” or “foolish seedling” in rice makes plants grow unusually tall, thin, and weak, often leading to lodging and yield loss. Scientists investigating this disease isolated a substance produced by the fungus Gibberella fujikuroi, which caused the abnormal elongation. This substance was named gibberellin. Historically, this research began in Japan, where rice is a staple crop and such diseases have serious economic impact. To answer, we must connect the term gibberellin and the “foolish seedling” disease with Japanese plant pathology and physiology research.

Step-by-Step Solution:

Verification / Alternative check:
Standard botany and plant physiology textbooks typically state that gibberellins were first discovered in Japan when scientists were investigating the bakanae disease of rice. They describe how extracts from the fungus caused rice seedlings to exhibit the same overgrowth symptoms, leading to isolation and naming of the hormone. There is no similar claim for India, China, or Russia as the country of initial discovery, which strongly verifies that Japan is correct.

Why Other Options Are Wrong:
India is a major rice-growing country and has contributed greatly to agricultural research, but the first discovery of gibberellin was not made there. China also grows a large amount of rice, yet historical accounts of gibberellin discovery point to Japanese scientists as the pioneers. Russia contributed to plant physiology in other areas, but not to the initial identification of gibberellins in the bakanae context. Therefore, these countries do not match the historical origin of the hormone’s discovery.

Common Pitfalls:
Students sometimes guess India or China because they associate rice production with those countries or because they are familiar from their own regional context. Others simply pick any rice-growing nation without recalling the specific term “bakanae” and its Japanese origin. To avoid this, remember that both the disease name and the fungus name Gibberella fujikuroi are linked with Japan, which provides a strong clue that the discovery of gibberellin also took place there.

Final Answer:
The plant hormone gibberellin was first discovered in Japan while studying the "foolish seedling" disease in rice.