Effects of innovative plant biostimulants on Lactuca Sativa l.

The growing demand for food, feed and raw materials and the increasing ecosystem degradation impose the use of more sustainable methods in the agriculture production systems. In last years, the use of plant biostimulants has given a huge boost to the exploitation of several biomolecules and microorganisms able to promote natural processes to enhance/benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, and crop quality. Thus, the development of new plant biostimulants with high activity has become an important focus of research interest. The aim of our research was to investigate the biostimulant action of several biomolecules (enzymes and polysaccharide) on biomass and bioactive compounds of lettuce (Lactuca sativa L.), one of the most widely consumed leafy vegetables worldwide, and a significant source of antioxidants and bioactive compounds. Lettuce plants were grown in greenhouse and irrigated, at weekly intervals, with 12 solutions (namely S2-S13) containing the selected biomolecules as single compound or in multiple combinations. Untreated control plants were irrigated with the S1 solution corresponding to the buffer of our biostimulants. Compared to control plants, all biostimulant solutions gave a statistically significant increase (up to 12 %) of the Soil Plant Analysis Development (SPAD index), a non-destructive measurement of leaf chlorophyll content. A statistically significant increase (up to 21 %) of dry plant biomass was observed only with two biostimulant solutions (S2 and S3) containing single enzyme or a mixture of two enzymes, respectively. Currently, biochemical and molecular analyses are underway to determine the effects of all treatments on total phenols content and on genes involved in their biosynthetic pathways. Future work will be required to further investigate their efficacy in different environmental conditions and/or plant species.