
TY  - JOUR
A1  - Rajagopal, V 
A1  - Rao, IM 
T1  - 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)
JF  - Australian Journal of Botany
JO  - Aust. J. Bot.
Y1  - 1974
VL  - 22
IS  - 3
SP  - 429
EP  - 435
KW  - 
UR  - https://doi.org/10.1071/BT9740429 
N2  - 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. 
ER  -

