Physiological disorders of the nicotianamineauxotroph tomato mutant chloronerva at different levels of iron nutrition. I. Growth characteristics and physiological abnormalities related to iron and nicotianamine supply

The mutant chloronerva of Lycopersicon esculentum Mill. cv. Bonner Beste suffers from retarded growth of shoots and roots and a diminished chlorophyll content of the youngest leaves. The roots exhibit thickened tips and root hair zones as symptoms of iron deficiency. These abnormalities were diminished to a certain degree by an increased iron supply. Nicotianamine (NA) supply to the leaves leads to a shift in the mutant characteristics towards the wild-type (so-called phenotypical normalization). The relationships between expression of the genetic defect and iron nutrition and the degree of phenotypical normalization by exogenous NA are discussed.