Question

Utilization of N from atmosphere by legumes was first observed by:

• A. Jean-Baptiste Boussingault
• B. David Baltimore
• C. Martinus W. Beijerinck
• D. Sergei N. Winogradsky

Hint:

Boussingault is often called the "Father of Field Experimentation." He was the first to use chemical analysis to solve agricultural problems.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Biological Nitrogen Fixation (BNF) is the process where atmospheric nitrogen (\( N_2 \)) is converted into ammonia (\( NH_3 \)) by specific organisms.
The history of discovering this process involved several key scientists in the 19th century.

Step 2: Detailed Explanation:
Jean-Baptiste Boussingault (Statement 1), a French chemist and agronomist, conducted meticulous field experiments in the 1830s.
By performing nitrogen balance sheets on his farm, he demonstrated that legumes (like clover and alfalfa) could increase the nitrogen content of the soil and plant tissue beyond what was added as fertilizer, whereas cereals could not.
He concluded that legumes must be obtaining nitrogen from an "external" source, which he correctly identified as the atmosphere.
Martinus W. Beijerinck (Statement 3) later isolated the bacteria (Rhizobium) responsible for this in 18
Sergei Winogradsky (Statement 4) discovered free-living nitrogen fixation (e.g., Clostridium pasteurianum).
Boussingault's work was foundational as it proved the "fact" of nitrogen utilization by legumes, even before the microbiological mechanism was fully understood.

Step 3: Final Answer:
Jean-Baptiste Boussingault was the first to observe and document that legumes utilize atmospheric nitrogen.