Growth characteristics and nitrogen, carbon and nitrate concentration of red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.

Nitrogen (N) concentration in the nutrient solution is given in millimol per liter (mM). Photosynthetic photon flux density (PPFD) is given in μmol m−2 s−1. Head mass is given in gram fresh matter. Nitrogen, carbon (C) and nitrate (NO3) concentration is given in milligram per gram dry matter. Data was evaluated via two-way ANOVA, factors: mM N and PPFD, α = 0,05, followed by Tukey HSD test (mean, n = 3). Identical letters indicate that values do not differ significantly. Asterisks indicate significantly influential factors.Growth characteristics and nitrogen, carbon and nitrate concentration of red and green lettuce cultivated at different nitrogen concentration and photosynthetic photon flux density.