Effects of application of GABA and calcium lactate on photosynthesis and nitrate ‎accumulation in Lactuca sativa ‘Dimayo’ ‎

Nitrate uptake in plants is very important due to environmental concerns and the quality of agricultural products. On the other hand, photosynthetic efficiency is considered as the principal indicator of plant growth and yield, therefore the ability to sustain crop stability in different environmental conditions is crucial. In this study, some physiological characteristics and nitrate accumulation were investigated using γ-aminobutyric acid (GABA) and calcium lactate in lettuce of Dimayo cultivar. For this purpose, GABA solutions with three concentrations (0, 0.5 and 1.5 mg/l) and calcium lactate with three concentrations (0, 1 and 2 %) and their interaction were used, as foliar spraying during two times including after seedling transplant and two weeks later. This factorial experiment was performed in a completely randomized design in the greenhouse. GABA treatment of 1.5 mg/l + calcium lactate 2% showed the highest yield, total chlorophyll and relative water content. However, the highest ion leakage and nitrate accumulation were obtained in the leaves of control plants. Also, the lowest amount of nitrate accumulation was measured in GABA treatment with a concentration of 1.5 mg/l, which reduced the amount of nitrate accumulation compared to control plants by four times.