The aim of the present study was to evaluate the possible effects of two different biostimulant
formulations at different application regimes and combined or not with mineral fertilizers
(e.g., W1–W8, including the control treatment (no formulations added)) on the yield parameters and
fruit quality of watermelon plants. The highest yield was recorded for the W5 treatment due to the
formation of more fruit. The highest content of fat, proteins and ash was recorded for treatment
W1, whereas carbohydrates were the most abundant in the control treatment, resulting also in the
highest energetic value. The main detected sugars in all the tested samples were sucrose and fructose,
which were the highest for the W4 and W5 treatments (sucrose) and W4 treatment (fructose). Malic
and citric acid were the most abundant compounds, especially in the W4 treatment. In terms of
tocopherols, only -tocopherol was detected, with the highest amounts being recorded for the W4
treatment. Regarding bioactive properties, the lowest IC50 values for OxHLIA were recorded for
the W2, W3 and W8 formulations. Moreover, all the extracts exhibited significant anti-inflammatory
activity comparable to the positive control, while a variable efficacy of the tested extracts against
the studied bacteria and fungi was recorded. In conclusion, our results indicate that simple agronomic
practices such as biostimulant application may improve crop performance and improve the
proximal composition and the overall quality of watermelon fruit within the context of sustainable
crop production.
This research was funded by Agrology S.A., grant number 6089. The authors are grateful
to the Foundation for Science and Technology (FCT, Portugal) for financial support through national
funds FCT/MCTES to the CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC
(LA/P/0007/2020). In addition, national funding was received by F.C.T., P.I., through the institutional
scientific employment program contract for Â.F. This work is funded by the European Regional
Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope
of Project GreenHealth (Norte-01-0145-FEDER-000042).
