Influence of planting region and soil chemical properties on medicinal compound contents in Cistanche tubulosa

Abstract

Cistanche tubulosa is a valuable herbal remedy in China. In this study, we aimed to identify and analyze how bioactive compounds are affected by planting region and soil properties. Plant and soil samples in desert and alkaline-saline environments were collected, and measurements were obtained for (i) dry weight and medicinal compounds of plant samples and (ii) soil salinity and pH of soil samples. The effect of soil salinity on the medicinal compounds revealed that the dry weight per plant of C. tubulosa was relatively high in low salinity soil. However, under high salinity conditions, echinacoside and verbascoside contents increased. No visible effects of individual soil pH were found on dry weight and echinacoside, verbascoside, and mannitol contents. Regarding the interaction between soil salinity and pH, only mannitol content showed a significant difference. The mannitol content was unaffected by pH in the presence of slight salinity conditions; meanwhile, in severe salinity conditions, high pH dramatically lowered the mannitol content. In loam with saline soil, a lower dry weight per plant was observed but the planting density was higher. The good water and fertilizer retention abilities of loam can lead to a higher yield per unit area. To improve yield and quality simultaneously in the introduction regions, the crucial points for cultivation techniques of C. tubulosa in seashore saline land include a high seed dosage of C. tubulosa and moderate soil salinity