Question

Bakane disease in rice is associated with discovery of this plant hormone:

• A. Ethylene
• B. Cytokinins
• C. Abscisic acid
• D. Gibberellins

Hint:

Remember: "Bakane" = "Foolish" in Japanese. Tall, spindly, "foolish" growth is the hallmark of excessive GA concentration.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The history of plant hormone discovery often involves the study of plant diseases or unique growth phenomena. Bakane disease, also known as "foolish seedling" disease, was a major agricultural problem in Japan where rice seedlings grew excessively tall, became spindly, and failed to produce grains.

Step 2: Detailed Explanation:
1. The Pathogen: In the early 20th century, Japanese scientists (Kurosawa, Yabuta, and Sumiki) identified that the Bakane disease was caused by a fungus called {Gibberella fujikuroi (now Fusarium fujikuroi).
2. The Discovery: Eiichi Kurosawa (1926) found that sterile filtrates of the fungal culture could induce the same "tall seedling" symptoms in healthy rice plants. This indicated that the fungus was secreting a growth-promoting substance.
3. Isolation: Yabuta and Sumiki (1938) eventually isolated this substance in crystalline form and named it Gibberellin. It was later realized that plants produce their own version of these hormones to regulate natural stem elongation.
4. Thus, the study of the Bakane disease directly led to the discovery of the Gibberellins.

Step 3: Final Answer:
Bakane disease led to the identification and isolation of Gibberellins.