Soil with deficient inorganic elements promotes the accumulation of hesperidin , nobiletin  and tangeretin  in pericarps of Citrus reticulata ‘Chachi’

Aims: Environmental conditions, such as soil stress, are crucial for the accumulation of secondary metabolites in medicinal plants. This study aims to determine which soil type and environmental factors can promote the accumulation of hesperidin , nobiletin and tangeretin in the pericarps of Citrus reticulata ‘Chachi’ ( Citrus reticulata cv. Chachiensis). Methods: This study selected Citrus reticulata ‘Chachi’ planted in paddy soil, red soil, alluvial soil and conducted correlation between meteorological, soil factors and the three components. Then, linear regression models (LRMs) and random forest models (RFMs) were used to screen the soil factors affecting accumulation of the three components. Structural equation models (SEMs) were established to further explore how key soil factors affect the accumulation of the three components. Results: Our results indicated that there was no significant difference in meteorological factors among the three regions ( p  > 0.05), and no correlation was found between the meteorological factors and the three components. Soil factors in three soil types, such as K, Ca, Mg, Mn, salinity and pH, have significant impacts on the content variation of hesperidin , nobiletin and tangeretin . The deficiency of K and Ca, play a crucial role in the accumulation of the three components. Conclusions: Citrus reticulata ‘Chachi’ cultivated in soil with deficient K and Ca is more inclined to accumulate hesperidin , nobiletin and tangeretin in pericarps, which provides guidance for reasonable cultivation and paddy, red and alluvial soil improvement to promote the contents of medicinal components and the quality of medicinal plants.