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Tomato cultivars respond differently to nitrogen (N) sources and to saline conditions, in terms of both yield and fruit quality. Interactions between salinity and ratios with tomato genotypes were studied. The effect of four ammonium levels (0, 1, 2, 4 mM of total 8 mM N) and two salinity levels (0 and 45 mM NaCl) on cv. “R-144”, and the effect of two salinity levels (0 and 45 mM NaCl) on four tomato hybrids (“R-144”, “R-175”, “FA612”, and “FA624”) were studied in two greenhouse experiments. The effects of two levels, (0 and 2 mM out of total N at 8 mM), and two salinity levels (0 and 20 mM NaCl) on large-fruit (“R-144”) and small-fruit (“FA612”) tomato hybrids were also studied in a net-house. The NaCl at 45 mM resulted in a smaller leaf area index (LAI), lower plant dry matter and lower fruit yield than controls. Addition of 1 mM to the nutrient solution contributed to improved growth. Genotypes bearing large fruits were more prone to suffer yield losses under saline conditions than those with ...

Fruit load in melon plants may cause a reduction in fruit quality especially when several fruits are ripening simultaneously on a single plant. Three experiments using Galia F1 hybrid (Cucumis melo L.) were conducted in an insect proof net house during the autumn (August–October) growing season in Israel. The plants were grown on silica pumice in a recycled hydroponic system. The influence of the duration of P application at four concentrations (0.3, 0.5, 0.75, and 1 mM P) in the nutrient solution (NS) on the number and quality of simultaneously ripening fruits were measured (Experiment 1). In a second experiment three levels of P in the NS (0.5, 0.75, and 1 mM) were tested on two concentrations of nitrate (2.6 and 5.2 mM). In a third experiment, two ratios of ammonium (10 and 20%) were tested each with two levels of N:P ratios (5.2 : 0.5 and 7.2 : 0.8 mM). Withholding phosphorus (P) at 10–26 or 10–33 days after germination (DAG) or delay in P (25–60 DAG) at concentration of 0.3 or 0.5 mM resulte...

Significant tomato matrix effects on the volatility of certain fresh tomato odorants were found. The concentrations of odorants such as (E,E)-2,4-decadienal, beta-damascenone, and beta-ionone, in crushed fresh tomato fruit obtained by solid-phase microextraction (SPME), resulting from a tomato matrix calibration curve were 5.5-, 2-, and 12-fold higher, respectively, than those calculated by calibration based on buffer solutions. Static headspace analyses indicated that, in most cases, the tomato matrix significantly retains the odorants relative to the buffer solution. Thus, the concentration of odorants in the headspace of tomato is lower than expected compared to a simple matrix such as buffer. CaCl(2), although needed in crushed fruit tissue to block enzymatic activity, was found to interact specifically with 2-isobutylthiazole, reducing its content in the headspace by at least 6-fold. If a matrix effect is found, analysis of the odorant molecule contents in the headspace rather than in the food is recommended in order to better evaluate their access to the olfactory receptors.