The Effects of Hypergravity and Radiation Exposure on Plants and their Terrestrial and Space Applications

Introduction: The Bellagio II Summit discussed several aspects related to space nutrition, space pharmacy and the influence of the space environment on plants and their compounds. Plant germination and growth are influenced by innumerous environmental factors, such as the level of gravity and type of radiation. Since several plants have nutritive and medicinal value, the importance of their cultivation and consumption during space missions are unquestionable. Studies have demonstrated that simulated hypergravity through centrifuge exposure increases the number of seed germination, accelerates plant growth and the modifies metabolitesproduced by some plants. The radiation of space, either in Low Earth Orbit or in deep space, can also positively impact on plant growth and metabolite production.Methods: The effects of different levels of gravitational fields and types of radiation on plant germination and development were reviewed for application in space missions and food and pharmaceutical industries on Earth.Results: Faster germination and increased growth of Rocket plant seeds, as well as higher rates of germination of carrot seeds were observed when subjected to intermittent exposure at +7Gz. The scientific literature shows that using UV-C radiation (non-ionizing radiation) on arugula increased its production of antioxidant and polyphenols compounds, and shortened strawberry maturation by 4 to 8 days, without affecting the average weight of the fruit. Gamma (ionizing) radiation, however, reduced the average height of fava beans, but did not affect germination. It can also be used to disinfect vegetables.Discussion: This paper reviewed the literature related to the effects of hypergravity conditions, as well as different types of radiation exposure on the plant life cycle and production of their compounds. The findings reviewed suggest that several plants present faster rates of germination and growth under hypergravity conditions. This may motivate the cultivation of such plants and vegetables using this method, not only on Earth, but also in more extreme environments, such as those found on space stations and extra-terrestrial bases. Studies conducted worldwide have demonstrated the potential advantages of applying radiation onplants. Hypergravity and radiation exposure, therefore, might be useful for terrestrial applications, especially in food production and medication development.