Effects of Nutrient Solution Electrical Conductivity and pH on the Productivity of the Medicinal Plant Pinellia ternata Breit.

Medicinal plants (Pinellia ternata Breit.) were cultivated under four nutrient solution conditions, namely a pH of 4 and electrical conductivity (EC) of 2.2 mS cm^-1, pH of 4 and EC of 1.2 mS cm^-1, pH of 6 and EC of 2.2 mS cm^-1, and pH of 6 and EC of 1.2 mS cm^-1. Plants were grown for 15 weeks in phytotron glass rooms controlled at an air temperature of 25℃ and a relative humidity of 70%. The leaf number per plant was measured every week, the leaf chlorophyll content (SPAD) was measured at 100 d after planting, and the corm yield and the effective ingredient, namely araban, content in the corm were evaluated after 15 weeks of cultivation. No clear effects of the nutrient solution EC and pH on the corm growth, the corm quality, and leaf chlorophyll content were not observed in this experiment. The EC and pH of the nutrient solution will not affect the productivity of the P. ternate in the ranges of EC 1.2–2.2 mS cm^-1 and pH 4–6, respectively.