Response of potato (Solanum tuberosum L., cv. Iwa) nodal explants to low inorganic nitrogen supply in vitro

Abstract The effect of low inorganic nitrogen (N) supply on potato plantlets developed from nodal explants cultured in vitro on modified Murashige and Skoog media supplemented with 3% sucrose was investigated. Lowering the inorganic nitrogen supply from 60 mM to 1.88 mM, while keeping the ratio of ammonium and nitrate at 0.52, did not result in a significant decrease in the fresh and dry weights of the plantlets, the number of new leaves formed and shoot length. Moreover, the plantlets cultured on the medium supplemented with 3.75 and 7.5 mM inorganic N exhibited greater biomass and shoot lengths than those on the medium with 60 mM inorganic N. Lowering the inorganic N supply in the media resulted in increased chlorosis with accompanying decreases in the chlorophyll and carotenoid contents of the leaves, but faster development of lateral roots and increased phenolic content in the roots.