NITRATE MEASUREMENTS IN PROCESSING TOMATO LEAVES BY A QUICK TEST
In two plots of a field of processing tomato cv Brigade grown with a nitrogen (N) fertilization equal to 110 kg N ha‑1 or to 298 kg N ha‑1 the leaf NO3-N concentration was estimated in recently mature leaf samples collected every week, for twelve weeks, by a quick test (QT) in fresh material and also in the same samples by the ion chromatography (CH) method after drying and grinding. The NO3-N concentration in the dry matter of petioles measured by QT (NO3-N)QT ranged from 74 to 5584 mg kg‑1 and from 202 to 5924 mg kg‑1 dm in the low N and high N treatments, respectively, while the concentration of NO3-N measured by CH (NO3-N)CH ranged from 262 to 10518 and from 657 to 15405 mg kg‑1 in the low N and high N treatments, respectively. The values of NO3-N in petioles and blades decreased over the crop development according to typical data from literature. Petioles gave a closer correlation (higher R2) between (NO3-N)QT and (NO3-N)CH than the blades and thus could be considered as better indicator plant part for shoot nitrate content evaluation. The linear regression between the NO3-N values measured by the QT and the CH in all the analysed plant samples (n=48) resulted in the linear relationship: (NO3-N)QT=0.44*(NO3-N)CH+17.75 with R2=0.93.
Christou, M., Vassiliou, Z., Liakopoulou, N. and Dumas, Y. (2003). NITRATE MEASUREMENTS IN PROCESSING TOMATO LEAVES BY A QUICK TEST. Acta Hortic. 613, 177-180
Nitrogen fertilization, leaf petiole, leaf blade, ion chromatography, Lycopersicon esculentum