H. Nonami, K. Mohri, T. Fukuyama, Y. Hashimoto
In plant factories, hydroponic culture is used commonly for cultivating seedlings, and changes in concentrations of nutrient solutions used in hydroponic culture cause changes in growth of plants. In the present study, kidney bean (Phascolus vulgaris L.) seedlings were used to study how ion compositions in the nutrient solution influenced the growth and water status of the seedlings when water stress was applied by either increasing concentrations of the nutrient solution or by adding additional NaCl, KCl or CaCl2 to the hydroponic culture solution. Ion permeability through the root tissue was measured with a pressure chamber. When water stress was applied to the root, the root growth was inhibited immediately, and subsequently the stem growth was inhibited. Water potential of the root decreased most rapidly in Ca-treated plants, and most slowly in K-treated plants. Permeability of Ca ions was the lowest and K permeated the root tissue well. In the stem elongation zone, water potential decreased most rapidly in Na-treated plants and slowly in Ca-treated plants. Turgor of cells in the stem elongation zone increased most in K-treated plants due to a rapid decrease in osmotic potential. Although the nutrient solution contained a large proportion of K and Ca ions as ionic components, the water status of tissue did not coincide with phenomena observed in K- and Ca-treated plants. This indicates that a solution composed of a variety of ions influences absorption and water status completely differently from what one might expect from a solution composed of single ions. Thus, the composition of nutrient solution perhaps should not be decided solely by studying physiological function of single ionic components.
Nonami, H., Mohri, K., Fukuyama, T. and Hashimoto, Y. (1992). GROWTH REGULATION OF PLANT SEEDLINGS BY ION CONCENTRATION MANAGEMENT IN HYDROPONIC CULTURE. Acta Hortic. 319, 477-482
DOI: 10.17660/ActaHortic.1992.319.74

Acta Horticulturae