Plant material - potato
Plant cultivation and stress treatments of two genotypes contrasting in
their N deficiency response, namely ‘Lambada’ (sensitive) and ‘Topas’
(tolerant), were performed exactly as described (Jozefowicz et al.,
2017). At the time of root appearance, after one week of cultivation,
the nutrient solution was exchanged. Control plants were moved to fresh
medium containing the original 20.6 mM
NH4NO3 and 18.8 mM KNO3)
and the plants for deficiency treatment were transferred to a medium
with 1/16 of the N level. The loss of K (as a result of withholding
KNO3) was compensated by the addition of KCl. After
seven days, roots were harvested, snap-frozen in liquid
N2 and stored at -80 °C. The experiment was performed in
triplicate with six vessels per condition and cultivar.