Nitrogen from the air?

[tucker85]

A question for you scientists out there. Can orchids, or any other plant for that matter, use nitrogen taken directly from the air?

[isurus79]

Orchids cannot pull nitrogen from the air. As far as I know, only plants that are considered legumes can do this. Plants like peas and mesquite trees are in this group.

[gnathaniel]

I think yes; AFAIK all plants that fix nitrogen from the air actually do so by symbiotic association with various bacteria and fungi, which do the chemical work. Legumes have root nodules to house nitrogen-fixers, Tillandsias like FL-native recurvata host microbes on their leaves, and a couple of papers online seem to show that other epiphytes including orchids can have these associations as well:

Nitrogen Fixation in the Phyllosphere of Tropical Plants

Detection of Nitrogen-fixing ability in an Epiphytic Orchid Vanda testacea