Nicotiana sylvestris spent cell culture medium as a potential component of plant biostimulants to improve plant growth and nitrogen use efficiency in greenhouse cherry tomato

In horticultural systems, integrating plant biostimulants (PBs) with reduced N fertilization can reconcile adequate productivity and more sustainable N management. PBs can be sourced from several matrices, but limited research has investigated plant-based cosmetic by-products as a source of PBs to enhance crops’ resilience to reduced N availability. This study explores the use of a foliar-sprayed spent cell culture medium obtained from Nicotiana sylvestris (Nicotiana) under two N levels, assessing its impact on plant physiology, growth and NUE in hydroponically grown cherry tomato plants. The experiment was conducted using nutrient solutions containing11 and 4 mM N (N11 and N4, respectively), including also untreated plants (control) and plants sprayed with a commercial PB (Ilsac-on®). Compared to N11, N4 reduced leaf chlorophyll content (-9%), CO2 assimilation rate (-27%), Fv/Fm ratio (-10%), leaf area (-22%), root and aboveground biomass (-29 and -12%, respectively), whereas promoted Ci and root length (+12 and +8%, respectively). When compared to control, Nicotiana application affected CO2 assimilation rate (+20%) and Ci (-12%), whereas both foliar treatments increased root length, leaf area and aboveground biomass (on average by 11, 14 and 18%, respectively). Total N accumulation in plant and NUE were both influenced by N4 (-41 and +136% compared to N11, respectively), whereas both foliar-sprayed products promoted NUE (+20%). Our study demonstrates the potential of using N. sylvestris spent cell culture medium to improve cherry tomato responses under both nitrogen supplementation levels, highlighting its potential to support low-input cultivation practices in horticultural systems.