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Microspheres/microcapsules loaded with chemical and biological agents – a new type of biofertilizers

Trichoderma species are known as important biocontrol agents as well as a promotor of plants growth. Loading in biopolymer matrices has been recognized as an effective method for controlled release of T. species used for plant protection and nutrition. Calcium is an essential plant nutrient and its lack causes a significant plant physiological disorder. Simultaneous addition of calcium chloride and biocontrol agents can improve the activity of biocontrol agents due to their synergistic interactions. The main aim of simultaneous addition of Trichoderma viride (STP) spores and calcium ions loaded in alginate matrix are to protect the bioactive components and successful delivery of both active agents at the right place and the right time. We have developed and characterized alginate microspheres and microcapsules (with chitosan layer) prepared by the ionic gelation using calcium chloride as a crosslinking agent and loaded with T. viride spores. The in vitro results pointed out remarkable differences in the release behavior of T. viride spores and calcium ions on calcium chloride concentration and the presence of chitosan layer on microcapsule surface. The increase in calcium chloride concentration promoted, but the chitosan layer on microcapsule surface slowed both, T. viride spores and calcium release. Applications of novel microspheres/microcapsules during hydroponic tomato cultivation revealed the better development of seedlings, buds and fertilization, number and weight of fruits, and maturation. The most significant effect of the application was observed in the increasing number of the tomato fruits. The amount of most important active components in tomato fruits (lycopene, beta-carotene, calcium ions, total phenol content and their DPPH/ABTS antioxidative profile) was also investigated. Tomato fruits reached a significant increase in almost all measured parameters compared to the control. According to our findings, this is also a unique attempt to apply biologically (T. viride spores) and chemically (calcium ions) bioactive components on hydroponic tomato cultivation that would be of particular importance to ecological growth and in the process of functional food production.

microspheres (microcapsules), Trichoderma viride (STP), calcium ions, hydroponic cultivation, tomato

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