Evaluation of the growth and metabolic response of grapevine saplings in different doses of five commercial biostimulants

A challenge in todayRSQUOs agriculture is to increase production by using as small quantities of inputs as possible with small environmental footprint. The aim of this study was to evaluate the action and appropriate dose of five commercial biostimulant formulations in grapevine saplings Vitis vinifera L. The work took place in a greenhouse of the agricultural school of the University of Ioannina. The experiment was performed in a completely randomized design, with 3 replications and 16 treatments including a control one (where no biostimulants were applied) (0), in pots (9 L) within 114 days from June to October 2021. A clay soil composition with perlite in a ratio of 5:1 was used as a growth substrate. The following biostimulant formulations were applied as aqueous suspension to the grapevine samplings in the recommended dose of commercial formulations, as well in double and quadruple doses: HF) humic and fulvic acids (>25% w/w); GBP) glycine-betaine (80% w/w) - proline (10% w/w); SM) Sinorhizobium meliloti B2352 (2%w/w); BA) Bacillus amyloliquefaciens (96.69% w/w); and AA) amino acids (9.0% w/w). Plant growth parameters, length, fresh and dry weight, number of leaves, leaf area, and the plant total chlorophyll content were measured. Folin determination was performed to assess the total phenolic content of leaf tissue in plants and proline determination, to obtain the metabolic response of plants to abiotic stress under greenhouse conditions. Among the treatments, the most significant differences relative to control treatment, were those containing beneficial bacteria and amino acids, which resulted in the greatest plant growth. It was concluded that microbial biostimulants containing beneficial bacteria, amino acids and humic and fulvic acids can enhance plant growth even in greenhouse conditions. This is very promising in the future demands of agriculture for high yields even under abiotic stresses.