Application of biostimulants in tomato subjected to water deficit: Physiological, enzymatic and production responses

The objective of this study was to evaluate the effect of the application of the biostimulants Seed(+) and Crop(+) on physiological and production variables and on the activity of antioxidant enzymes (superoxide dismutase SOD and guaiacol peroxidase POD) in tomato plants subjected to two soil water conditions. The experiment was carried out in a greenhouse, in a 2 x 2 x 6 factorial scheme, with two times of application of the biostimulants (flowering and fruiting), two soil water conditions (50 and 100% of soil water holding capacity) and six biostimulants (control treatment; Seed(+); Seed(+) + Crop(+) 1x; Seed(+) + Crop(+) 2x; Crop(+) 1x; + Crop(+) 2x). The exprimental design was completely randomized, with four repetitions. The biostimulants Seed(+) and Crop(+) increased the quantum yield of photosystem II (Fv/Fm), regardless of the time of application and water condition of the soil. The biostimulants Seed(+) + Crop(+) 2x and Crop(+) 2x stood out in the pre-morning period, with an average Fv/Fm of 0.813, under the conditions tested. The highest SOD activity (372.12 U mg-1 of protein) was obtained with Crop(+) 2x biostimulant in fruiting and under water deficit. For POD, when under water deficit, the best results were obtained with the biostimulants Seed(+) + Crop(+) 2x, Crop(+) 1x and Crop(+) 2x in flowering (810.94; 691.19 and 921.59 U mg(-1) protein) and in fruiting (703.60; 800.00 and 972.62 U mg(-1) protein). Thus, the use of Seed(+) and Crop(+) biostimulants can be an alternative to help mitigate the damage caused by water deficit in tomato crop.

Automated summary

The study evaluated the effects of applying biostimulants Seed(+) and Crop(+) on physiological and production variables, as well as antioxidant enzyme activity, in tomato plants under different soil water conditions. The results showed that the biostimulants improved the quantum yield of photosystem II and enzyme activity, indicating their potential as a mitigation strategy for water deficit in tomato crops.