[Raven]

Ακριβως ετσι. Οι τιμες τους ομως ειναι πολυ μικρες και τα φυτα στρεφονται προς τα Νιτρικα που ειναι πιο σταθερη η συγκεντρωση τους.
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Δημητρη το εχω ξανασυναντησει το θεμα μεσα απο συζητηση σε ξενο forum:


Quote:
nope. plants prefer what's most available, NH4+ or NO3. However, they prefer NH4... When plants take in NO3, it take energy to for it to convert it back to NH4, which it needs for N.

Maybe I'm not understanding your post, but I think we agree. Yes, plants do prefer NH3/4, but as you say--it takes energy to switch back and forth, so once they are setup to uptake N03....they are somewhat reluctant to switch back to NH3/4 just because a little bit has become available. If I understood things correctly, that's why plants don't really focus on NH3/4 until ~0.5ppm, because N03 is generally more abundant and uptaking NH3/4 requires a switch....This low NH3/4 level niche is something that some algae have adapted to take advantage of....
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