Effects of irrigation regime, leaf biostimulant application and nitrogen rate on gas exchange parameters of wild rocket
Biostimulants can have physiological effects on plants that improve yield, quality, and nutrients use efficiency. The mechanisms activated by these compounds are unknown and are difficult to identify, because the most part of these substances is composed mainly by plant extracts, algae extracts, amino acids, vitamins and mineral nutrients. Therefore, their effect is the result of many components that may work synergistically. In the recent years, the biostimulants are gaining importance for their possible use in organic and sustainable agriculture. The results of a study conducted to assess the interactive effects of irrigation regime, leaf application of a biostimulant based on brown seaweed extract and nitrogen rate on leaf net photosynthesis (A), transpiration (T), stomatal conductance (gs), internal CO2 concentration (Ci) and intrinsic water use efficiency (WUEi), are reported. The research was carried out during November-February 2016-2017, under greenhouse located in southern Italy. Two irrigation regimes (restoration of 100 and 50% of crop evapotranspiration, respectively named I100 and I50), two leaf biostimulant application (Bioproject SM23-BioKimia® International S.r.l., and a control without biostimulant, respectively named B and C) and three nitrogen rates (0, 75 and 150 kg ha-1 N, respectively named N0, N1 and N2) on wild rocket [Diplotaxis tenuifolia (L.) DC.] grown in pots, were compared. A split plot experimental design with three reps was utilized. All treatments affected gas exchange parameters. I50 in respect to I100 reduced A, T and gs, but improved WUEi, and the differences were raised with increasing soil water content gap between treatments. N rate increase improved A but, in condition of high water stress, the higher N rate was detrimental. Biostimulant improved A by 8.9% and WUEi by 7.5%, and the positive effect was greater in water shortage conditions. Positive effects of Bioproject SM23® on A and WUEi suggest its use to improve the performances of wild rocket and mitigate harmful effects of water stress.
Schiattone, M.I., Leoni, B., Cantore, V., Todorovic, M., Perniola, M. and Candido, V. (2018). Effects of irrigation regime, leaf biostimulant application and nitrogen rate on gas exchange parameters of wild rocket. Acta Hortic. 1202, 17-24
Diplotaxis tenuifolia, photosynthesis, transpiration, WUEi, water stress