
%0 Journal Article
%A Rajagopal, V 
%A Rao, IM 
%T Changes in the Endogenous Level of Auxins and Gibberellin-Like Substances in the Shoot Apices of Nitrogen-Deficient Tomato Plants (<I>Lycopersicon esculentum</I> Mill)
%J Australian Journal of Botany
%D 1974/09/01
%V 22
%N 3
%P 429-435
%K 
%R https://doi.org/10.1071/BT9740429
%U https://www.publish.csiro.au/paper/BT9740429 
%X Tomato plants were grown at three nitrogen levels: normal supply (control), moderate deficiency (one-eighth the normal supply &#8211; 1/8N) and acute deficiency (-N). Plant heights were reduced by 51.4 and 75.7 % respectively at 40 days under the latter two treatments compared with control plants. The biological activity of growth-promoting and growth-inhibiting substances was determined in the shoot apices of the three sets of plants at three stages: 20, 30 and 40 days after sowing. In general, the endogenous auxin was higher in control than in 1/8N and - N plants. The growth inhibitor level was higher in -N plants than in control and 118N plants. Gibberellin activity was less in nitrogen- starved plants than in controls. - N plants exhibited not only loss of gibberellins but an accumulation of inhibitors at the last stage. A negative correlation between growth promotors (auxins and gibberellins) and growth inhibitors was evident. The interaction between auxins, gibberellins and inhibitors is discussed. 
