Hydroponic Cultivation of Medicinal Plants-Plant Organs and Hydroponic Systems: Techniques and Trends

Medicinal plants are a globally important resource for the treatment of disease and improvement of human health, and the only form of healthcare used by millions of people. Currently, the status of many medicinal species is threatened by overharvesting caused by increasing demand. While many species have been cultivated in soil, the resulting material often contains lower levels of medicinal compounds than that of wild-harvested plants. Hydroponic cultivation of medicinal plants may provide sustainable access, with research demonstrating increased secondary metabolite content in some species compared to both wild and soil-grown plants. There are a variety of hydroponic systems and techniques available, each with its own advantages and disadvantages. As medicinal compounds are often localised within specific plant organs, selecting hydroponic systems that maximise the yield of the desired organs and metabolites is necessary. However, as of yet there has been no attempt to examine the literature with regards to the cultivation of specific plant organs of medicinal plants in hydroponics. This article explores the use of different hydroponic systems to cultivate medicinal plants and how the choice of system differs depending on the desired plant organ, as well as highlighting studies with novel outcomes that may provide value to the field.