Nitrogen is Available to Plants Only in the Form Of

Question

Nitrogen is available to plants only in the form of
A)N₂ in the atmosphere.
B)nitrite ions in the soil.
C)uric acid from animal excretions.
D)amino acids from decomposing plant and animal proteins.
E)nitrate ions in the soil.

Accepted Answer

The most readily available form of nitrogen for plants is in the form of nitrate ions (NO₃⁻) in the soil. While nitrogen gas (N₂) is abundant in the atmosphere, it is not easily usable by most plants without the help of nitrogen-fixing bacteria. Nitrite ions (NO₂⁻) are toxic to plants in large quantities and are usually converted to nitrate ions by other bacteria. Uric acid from animal excretions and amino acids from decomposing plant and animal proteins may contain nitrogen, but they must first be broken down by bacteria and converted to nitrate ions before plants can use them.