VEGETATIVE GROWTH, NUTRITIONAL STATUS AND YIELD OF TOMATO PLANTS GROWING UNDER SALINITY CONDITIONS AND DIFFERENT NO₃^–:NH₄⁺ RATIOS

The effect of salinity and NO₃^–:NH₄⁺ ratio on vegetative growth, mineral composition and yield of tomato plants was studied in a greenhouse culture experiment.
Seedlings of tomato (Lycopersicon esculentum Mill. cv.
Daniela) were transferred to 120-L tanks containing aerated modified Hoagland solution.
Treatments consisted of three NO₃^–:NH₄⁺ ratios (14:0, 12:2 and 10:4) combined with three salinity levels (0, 30 and 60 mM NaCl). There were four replicates of each treatment except for the 12:2 ratio, which had eight (for each salinity level), of which four were changed to the 14:0 ratio, 60 days after transplanting, when 3rd truss had set.
Salinity had a negative effect on shoot growth.
Ammonium reduced leaf and root fresh weight by about 21% and 24% respectively.
The detrimental effect of ammonium on shoot growth was higher for the low than for the high salinity level.
Salinity decreased leaf NO₃^– concentration (around 60%) and increased leaf Na⁺ and Cl^– concentration.
The presence of ammonium until the end of the experiment increased leaf Na⁺ and Cl^– concentration under the salinity treatments.
Total-N concentration in plant was higher in treatments with ammonium.
Salinity reduced total fruit yield regardless of the NO₃^–:NH₄⁺ ratio.
The increase of NH₄⁺ concentration in the nutrient solution decreased tomato yield.
In conclusion, vegetative growth and yield of tomato are impaired in the presence of ammonium in the nutrient solution when plants are irrigated with saline waters.

V International Symposium on Protected Cultivation in Mild Winter Climates: Current Trends for Suistainable Technologies

P. Flores, M.F. del Amor, M. Carvajal, J.M. Navarro, A. Cerdá, V. Martínez

Lycopersicon esculentum, ammonium, nitrate, stress

https://doi.org/10.17660/ActaHortic.2001.559.53