Nutritional characterization on growth and ionome profiles in Japanese wasabi cultivars ( Eutrema japonicum ) under hydroponics

ABSTRACTJapanese wasabi is traditionally cultivated in terraced fields with running stream water conditions which typically produce a high-quality of yield. Previous studies have explored some of the effects of water nutrient status under such conditions; however, the relationship between water nutrient status in these cultivation conditions and the growth and quality of wasabi is still completely unknown. We evaluated the effects of nutrient strength, inorganic nitrogen sources, and pH of the medium on the growth of wasabi plants. Then, we analyzed the photosynthetic capacity and the ionomes of two major Japanese wasabi cultivars (‘Onimidori,’ an early-growing green-stem type; and ‘Mazuma No.1,’ a late-growing red-stem type) grown under a range of pH conditions. These experiments were conducted using a hydroponic system. Wasabi plants showed the best shoot and root growth in 1/10- and 1/2-strength Hoagland’s solution with a 50:50 ratio of NH4-N:NO3-N. On the basis of the accumulation patterns of NO3−, amino acids, and chlorophylls, the 1/10-strength nutrient solution provided optimal conditions for wasabi growth. For both wasabi cultivars, the best shoot and root growth was in medium at pH 6.0. The photosynthetic capacity of ‘Onimidori’ was greater than that of ‘Mazuma No.1,’ suggesting that this may contribute to the faster growth of ‘Onimidori.’ Ionome analyses revealed tissue-specific mineral accumulation patterns and their differences among different pH conditions and between the two cultivars. Ionome-based multiple-regression analysis revealed a relationship between element concentration profiles in the wasabi plants, especially those in root, and the shoot growth. Wasabi plants are ammonium-sensitive and nitrate-preferring plants, in addition to relatively low nutrient requirements for optimal growth. The results of this study describe the basic nutritional characteristics of wasabi plants. These findings represent an important step toward optimizing fertilization to control wasabi quality and growth in the traditional flooded cultivation system.KEY WORDS: Ionomenitrogenphphotosynthesiswasabi AcknowledgmentsWe thank Jennifer Smith, PhD, from Edanz (https://jp.edanz.com/ac) for editing a draft of this manuscript.Disclosure statementNo potential conflict of interest was reported by the author(s).Supplementary materialSupplemental data for this article can be accessed online at https://doi.org/10.1080/00380768.2023.2276716Additional informationFundingThis work was supported by Kurita Water and Environment Foundation, number 19B001 (T.I.) and Urakami Foundation for Food and Food Culture Promotion (T.I.).