why cant higher plants take nitrogen directly from atmosphere?

Answer 1

There aren't any plants (lower or higher) that can utilize N2 on their own - Some higher plants have co-evolved with nitrogen fixing bacteria (Rhizobium) that fix nitrogen for them. Examples are plants in the pea family that have root nodules that house the nitrogen fixing bacteria.

Answer 2

It is true the biochemical pathway never developed in plants for atmospheric Nitrogen, only bacteria managed that. It is important to note that the process to make nitrogen into something useful is an intensive process that requires a very unique enzyme complexed with the metal Molybdenum. While Moly. is important in higher plants for other things, it lacks this enzyme that helps fix nitrogen. It is however, the lofty dream to bio-engineer all crops to behave like legumes. Whose to say they won't try to skip the middleman?

Answer 3

No. they can in reality take it in by the roots in the type of nitrates dissolved in the soil water. some flowers at the same time with those in the Pea relations have colonies of micro organism residing interior of nodules on the roots. those micro organism are waiting to 'restoration' atmospheric nitrogen and, by 2 or 3 degrees, bypass it to the host plant

Answer 4

They don't have the metabolic pathways for fixing atmospheric nitrogen, and have no intracellular structures for doing so.

Yes, I know that's like a "they can't because they weren't made that way" kind of answer.

Answer 5

because the nitrogen could not be utilised straight away. It has to be in nitrogen compound that to be utilised by plants

Answer 6

Higher plants are more specialized than lower ones. Nutrient intake is in the structure that has evolved for it. i.e. roots.

Answer 7

sounds silly but the fact is they aren't made that way - they could be but that isn't the path evolution took ( like we live in air and have no gills )