An innovative co-cultivation of microalgae in a hydroponic system for the sustainable development of a food and agriculture

Providing a population with high-quality food products is an important task in modern science and production. Global climate change has led to an increase in the frequency of natural hazards, such as floods, droughts, hurricanes, tornadoes, and frost. In addition, because of economic activity and irrational environmental management, the area of arable land has been reduced. These negative factors threaten crop production and global food security, and pose serious challenges to the production of staple foods through conventional agriculture. Hydroponics is a soilless farming method used to combat the shortage of cultivable land and improve food security in urban areas. In recent years, there has been a growing trend towards the use of microalgal inoculants as replacements for chemical fertilizers and non-renewable resources. The ncorporation of microalgae into hydroponic systems has many potential benefits. These organisms are biostimulants that positively affect plant growth by increasing their resistance to abiotic stress and nutrient absorption efficiency (Chiaiese et al., 2018). In a hydroponic system, there is often a symbiotic association between microalgae and plants, providing the root respiration of plants with oxygen produced by microalgal photosynthesis. The basic idea of our practice is co-cultivation vegetables together with algae. We grew cucumber plants together with Chlorella vulgaris – a model algae–in different physiological experiments in hydroponics. In our study, we created a simple hydroponic system (Vildanova et al., 2023). Cucumber seeds were soaked in distilled water in petri dishes for germination for 3 days. Glass cans with volumes of 150–200 mL were used as a simple hydroponic system. Knop solution was added to the Chlorella vulgaris suspension at a ratio of 1:1. Shoot and root lengths were measured using a ruler. Parts of the seedlings were laid on a filter paper until they were completely dry. Then, the weight of each shoot and root was measured on an analytical scale. During cultivation in a Knop medium with the addition of Chlorella suspension, the length of the shoots was shortened from 11.30 to 8.15 cm, while Root length also decreased from 16.41 to 10.59 cm. At the same time, root biomass increased from 0.04 0.05 g. Our research demonstrates that, under the influence of Chlorella vulgaris suspension, changes in the length of the shoots and roots do not always coincide with a difference in dry biomass. The change in biomass more accurately reflects the influence of algae because the shortening of shoots and roots is accompanied by an increase in their thickness. Thus, this study allows us to recommend it as a biostimulator for growth in hydroponic systems for wider use in agriculture.