The Relationship between the Growth Rate of Young Plants and their Total-N Concentration is Unique and Simple: a Comment

A series of experiments with cabbage and lettuce, where nitrogensupply is interrupted at a given and the future developmentof plants mass and of nitrogen concentration are observed, isre-analysed. Using the nitrogen productivity theory, it is shownthat plant properties determined from growth under unlimitednitrogen supply also explain the behaviour under interruptednitrogen supply. This is in contrast to the suggestion of theoriginal author Burns 1994, Annals of Botany 74: 143-157, whoquestions the existence of a unique relationship between plantrelative growth rate (RGR) and nitrogen concentration. Someserious problems in the models suggested by the author are alsoindicated.Copyright 1995, 1999 Academic Press Cabbage, lettuce, model, nitrogen limitation, nitrogen productivity, relative growth rate