Market is increasingly demanding vegetables with high quality and nutraceutical characteristics. Leafy vegetables can get benefit from biostimulants, for the reduction of nitrate concentration and the increment of antioxidants, with potential benefit for human health. This work was conducted by a team of researchers which included Roberta Bulgari, Giacomo Cocetta and Antonio Ferrante from DiSAA, in collaboration with Alice Trivellini of Scuola Superiore Sant’Anna Pisa. The research purpose was to investigate on the role of a novel plant-based biostimulant in affecting nitrogen and carbon metabolism in wild rocket (Diplotaxis tenuifolia L.). Foliar spray treatments were performed with extracts obtained from borage (Borago officinalis L.) leaves and flowers. To evaluate the treatments effect, in vivo determinations (chlorophyll a fluorescence and chlorophyll content) were performed. At harvest, nitrate concentration, sucrose, total sugars, chlorophyll, and carotenoids levels were measured in leaves. In order to characterize the mechanism of action also at molecular level, a set of genes encoding for some of the key enzymes implicated in nitrate and carbon metabolism was selected and their expression was measured by qRT-PCR. Interesting results concerned the increment of sucrose, coherent with a higher light use efficiency, in addition to a significant reduction of nitrate and a to the enhanced nitrate reductase in vivo activity. Also, genes expression was influenced by extracts, with a more pronounced effect on nitrogen-related genes. The data obtained allowed to broaden the knowledge related to the mechanism of action of this new class of products, currently of great interest. The reduction of nitrate is an important result which suggests the possibility of using biostimulants as important agronomic tools for the control of this molecule, which represents a potential problem for consumers, especially in the case of leafy vegetables
Bulgari, R., Cocetta, G., Trivellini, A., & Ferrante, A. (2020). Borage extracts affect wild rocket quality and influence nitrate and carbon metabolism. Physiology and Molecular Biology of Plants, 1-12. DOI:10.1007/s12298-020-00783-5.