Mother plant nutrition and growing condition affect amino and fatty acid compositions of hybrid sweet pepper seeds

The effect of mineral nutrition status of mother plant on the concentrations of amino and fatty acids and the emergence quality of hybrid sweet pepper seeds (cv. 'Hazera' 1195) was studied in two hydroponics experiments. Three concentrations of potassium (K) (0.5, 2.5 and 5.0 mM) combined with NH₄-N to NO₃-N ratios (mM/mM: 0/6.0, 0.9/5.1, 1.8/4.2 and 3.0/3.0) were conducted during the seasons from spring to summer and from autumn to winter, respectively. Seeds developed in the summer showed lower emergence percentage than those developed in the winter. When the mother plants were supplied by the same nitrogen (N) form and K concentration, the summer seeds contained significant higher K and chloride (Cl), total free amino acids, oleic acids, stearic acid, and palmitoleic acid, but lower phosphorus (P), calcium (Ca), magnesium (Mg), proline and linoleic acid than the winter seeds. No difference was found in the concentrations of N, sulfur (S), palmitic acid and total fatty acids of seeds between the two seasons. Replacing of 3 mM NO₃-N (50% of total N) by NH₄-N or the reduction of K concentration in the solution from 2.5 mM to 0.5 mM decreased proline, histidine, total amino acids, linoleic acid, and increased the ratio of oleic acid to stearic acid in the summer seeds. The correlation and stepwise regression analysis suggested that the emergence percentage of seeds developed in the summer was positively correlated to the proline concentration, but negatively correlated to the concentrations of Cl and K and the ratio of oleic to stearic acid.