Biostimulant effects of algae species, arbuscular mycorrhizal fungi and their combinations on yield and quality of yellow tomato landrace

Recent agricultural research has prioritized the development of environmentally friendly management strategies to ensure food security, among which the application of biostimulants such as brown algae extracts, arbuscular mycorrhizal fungi (AMF) and their combination. The experimental protocol was based on the comparison between seven biostimulant treatments (three brown algae species, Cystoseria spp. – C.T., Fucus vesiculosus – F.V., Padina pavonica – P.P.; Arbuscular mycorrhizal fungi – AMF; C.T. + AMF; F.V. + A.M.F.; P.P. + AMF) plus an untreated control, in terms of effects on tomato yield, fruit quality, antioxidant properties, and biochemical activities. Plants treated with F.V. and P.P. brown algae extracts and A.M.F. + F.V. produced the highest number of fruits (20.3 plant-1 on average). The highest tomato yield was recorded under the application of the P.P. extract (57.9 t ha-1), though all the treatments resulted in higher production compared to the untreated control. The P.P. extract led to the highest hydrophilic antioxidant activity and total ascorbic acid levels (5.78 eq. 100 g-1 f.w. and 226.6 mg g-1 f.w., respectively), whereas the lipophilic antioxidant activity was best affected by the A.M.F. + P.P. combination (14.1 trolox eq. 100 g-1 f.w.). Catalase activity was enhanced at most by the A.M.F. + P.P. combination (3.3 mmol min-1 mg-1 Prot), whereas the highest GPOX value (25 mmol min-1 mg-1 Prot) was recorded upon the P.P. application, both treatments leading to the encouragement of enzymatic antioxidant mechanisms. Overall, our study highlights the potential of biostimulants, particularly brown algae extracts and their combination with A.M.F., to improve tomato yield, antioxidant properties and biochemical activities.