Fundamental Study on Plant-based Regenerative Life-support Systems with Sweetpotato Culture in Space

Abstract

Life support of crew in long-duration space missions will be highly dependent on supply of food, O₂ and clean water regenerated by plants in space farming. Therefore, the space farming system with scheduling of crop production, obtaining a high yield with a rapid turnover rate, converting atmospheric CO₂ to O₂ and purifying water will be important. Sweetpotato has been one of candidate crops in space farming. Sweetpotato has a high yield of edible biomass with a little inedible part as waste, because it can be utilized for the leafy vegetable as well as the root crop. In this study, nutritional values of tuberous roots and shoots of sweetpotato were investigated and the balance of yields of tuberous roots and shoots including stems and leaves was examined in order to obtain a fundamental knowledge of harvest management for tuberous roots and shoots as edible biomass in a single leaf and node cutting culture method applicable in space farming. As a result, sweetpotato can be utilized for the leafy vegetable as an antioxidative functional diet as well as the root crop as a high energy diet. Harvest timing of lateral shoots influenced the balance of the biomass yields of tuberous roots and shoots. Frequent harvest of young lateral shoots from plants sustainably having an unfolded leaf increased the tuberous root yield with the less lateral shoot yield and maintained mostly the constant total edible biomass yield.