Response of tomato plant to ammonium and nitrate nutrition using the relative addition rate technique

Different N sources (NO₃^–, NH₄⁺, or NH₄NO₃) at relative addition rate (RAR) of 0.25 day^‑1 were supplied to tomato (Lycopersicom esculentum Mill.), a species sensitive to NH₄⁺ toxicity.
At RAR 0.25 day^‑1 growth reduction occurred by NH₄⁺ application, slightly.
Tomato roots had a more efficient NH₄⁺ assimilation than shoots when N was supplied solely in the form of NH₄⁺, and dominant amino acids in tomato were glutamine and asparagine.
Low tissue levels of calcium and magnesium in the NH₄⁺-fed plants constituted part of the NH₄⁺-toxicity syndrome.
The supply of NO₃^– led to the accumulation of Fe in tomato roots, but leaves Fe concentration in NO₃^–-fed plants was low in comparison to NH₄⁺ supply.
It is concluded that due to the high sensitivity of tomato to NH₄⁺, even at RAR 0.25 day^‑1 the relative addition rate technique was not able to reduce the deleterious effects of NH₄⁺ in tomato plants.

I International Conference and X National Horticultural Science Congress of Iran (IrHC2017)

H.R. Roosta, J.K. Schjoerring

amino acid, ammonium, Lycopersicon esculentum, nitrate, relative addition rate technique

https://doi.org/10.17660/ActaHortic.2021.1315.73