Comparative study of Zn deficiency in L. sativa and B. oleracea plants: NH4+ assimilation and nitrogen derived protective compounds

• L. sativa would be more suitable than B. oleracea for growing in soils with low Zn availability.
• NO3− reduction and NH4+ assimilation are reduced and photorespiration is enhanced by Zn deficiency in both species studied.
• Zn deficiency changed the free AAs profile in both species studied.
• Gly accumulation could help L. sativa plants to accumulate more Zn in deficiency conditions.
• B. oleracea is able to accumulate N derived protective compounds to cope with Zn deficiency stress.

Zinc (Zn) deficiency is a major problem in agricultural crops of many world regions. N metabolism plays an essential role in plants and changes in their availability and their metabolism could seriously affect crop productivity. The main objective of the present work was to perform a comparative analysis of different strategies against Zn deficiency between two plant species of great agronomic interest such as Lactuca sativa cv. Phillipus and Brassica oleracea cv. Bronco. For this, both species were grown in hydroponic culture with different Zn doses: 10 μM Zn as control and 0.01 μM Zn as deficiency treatment. Zn deficiency treatment decreased foliar Zn concentration, although in greater extent in B. oleracea plants, and caused similar biomass reduction in both species. Zn deficiency negatively affected NO3− reduction and NH4+ assimilation and enhanced photorespiration in both species. Pro and GB concentrations were reduced in L. sativa but they were increased in B. oleracea. Finally, the AAs profile changed in both species, highlighting a great increase in glycine (Gly) concentration in L. sativa plants. We conclude that L. sativa would be more suitable than B. oleracea for growing in soils with low availability of Zn since it is able to accumulate a higher Zn concentration in leaves with similar biomass reduction. However, B. oleracea is able to accumulate N derived protective compounds to cope with Zn deficiency stress.