Question

Why nickel is not strictly essential elements for plant growth?

Answer 1

as nickel is micronutrient and only use in small amount by plant ..
so nickel have onle one role in plants that is activation of urease
hope this will help you ...

Answer 2

Answer:

Nickel is a component of some plant enzymes, most notably urease, which metabolizes urea nitrogen into useable ammonia within the plant. Without nickel, toxic levels of urea can accumulate within the tissue forming necrotic legions on the leaf tips.