The Effect of Plant-Derived Biostimulants on White Head Cabbage Seedlings Grown under Controlled Conditions

The aim of this study was to investigate the potential of using natural raw materials that have not been used for the production of biostimulants of plant growth. These products can effectively contribute to overcome the challenge posed by the increasing demand for food. Ultrasound assisted extraction (UAE) was chosen to prepare innovative biostimulants. The expected outcome of this research was to generate products that show beneficial effects on white head cabbage growth, development, and nutritional quality. The results proved that higher plants (mugwort, calendula, purple coneflower, chamomile, basil, giant goldenrod, comfrey, dandelion, and valerian) can be successfully used for the production of biostimulants. For example, products based on common dandelion showed the highest biostimulating activity. In a group treated with 2.5% flower extract, cabbage shoots were 37% longer, whereas in a group treated with 0.5% leaves extract, roots were longer by 76% as compared with a control group treated with water. Biostimulants based on common mugwort (at a dose of 0.5%) and common dandelion (root) (at a dose of 1.0%) increased the mass of cabbage shoots and roots by 106% and 246%, respectively. The majority of biostimulants increased the content of photosynthetic pigments (chlorophyll and carotenoids) and decreased the content of polyphenols. Botanical extracts also showed varied impact on the antioxidant activity of cabbage. Taking into account the benefits for a wide scope of applications, it is expected that the utilization of these types of products should increase in the future. These products can play a key role in sustainable agriculture.