Question

Does pant absorb Ammonia or nitrate.?

Answer 1

Plants absort anything in the soil, ammonia, ammonium ion, nitrate ions, ...even gold and silver ions ...

This absorption is due to concentration difference. If concentration of something is more outside the plant body, tge roots will absorb it.

But, plants require both ammonia or ammonium ions and nitrate ions . Ammonia is used to store nitrogen, while nitrate is used as a method to easily produce nitrogen or to directly use for amino acids.

Ammonia is mainly used for transport. It is used in large plants, to help plant to transport nitrogen from roots to topmost leaves , by creating concentration difference.

What plants actually need for metabolism is nitrogen. Nitrogen is needed for amino acid synthesis. This nitrogen can be derived easily from nitrates.

So, to summarize,
plants need ammonia and nitrate.

Ammonia is for storage.
Nitrate is for direct use for amino acids.