Endive (Cichorium endivia L.) is a leaf vegetable with high vitamin and nutritional values. Therefore, an increase of its cultivation in Poland and other European countries has been observed in recent years. The aim of this research was to study the effect of different growth media on the quality and photosynthetic efficiency of different endive cultivars. The experiment was conducted in controlled greenhouse conditions. Endive was grown in three independent NFT cultivation systems: a standard culture medium (control, A1), a culture medium concentrated three-fold (A2) and a medium concentrated five-fold (A3). Four cultivars were used: ‘Kethel’, ‘Barundi’, ‘Galanti’ and ‘Perceval’. The plants were examined for the number and weight of fully-grown leaves and the weight of roots, dry matter content and chemical quality attributes of endive such as ascorbic acid (AA), total soluble solids (TSS), chlorophyll and proline. In addition, several physiological traits such as modulated chlorophyll a fluorescence were measured.
Both three-fold and five-fold increases of ion concentration in the nutrient solution induced stress in the endive plants. Our results showed that the photosynthetic efficiency of the tested endive plants was affected by the cultivar factor and only the highest (five-fold) ion concentration in the nutrient solution. Growth under a medium of three-fold ion concentration did not affect the photosynthetic efficiency, despite observed changes in the growth and quality parameters of the endive plants. This study suggests that the type of fluorescence measurements used in this experiment (modulated) cannot be recommended as a sufficient bioindicator during endive production.