The Growth Characteristics and Ginsenoside Content in Two-year-old Panax notoginseng under Potassium Regimes

Purpose To explore the effects of different potassium levels on agronomic traits and quality traits of the two-year-old Panax notoginseng.

Method The effects of different potassium levels 0, 225, 450, 900, 1 350 kg/hm² potassium oxide (K₂O) on the appearance, biomass, leaf anatomical structure and saponin content of two-year-old P. notoginseng were examined by pot experiment.

Result At the 450 kg/hm² level of potassium, the plant height, crown width, leaf area, stem diameter and plant dry weight of P. notoginseng reached a maximum value, however, there were no significant differences in root-shoot ratio, root-mass ratio and leaf-mass ratio. At the 900 kg/hm² level of potassium, the number of fibrous roots were the most, and at the 450 kg/hm² level of potassium, the taproot length, tuber root length, tuber root diameter and root volume reached the maximum. Leaf thickness, upper epidermis thickness, palisade tissue/sponge tissue and palisade tissue/leaf thickness were significantly lower than those of other potassium treatments at 450 kg/hm² potassium level. Both the percentage of total saponins in rhizome and taproot reached the maximum value at the level of 450 kg/hm² potassium level, and the highest percentage of total saponins in fibrous root was appearance under 1 350 kg/hm² potassium level. The content of total saponins per plant of rhizome, taproot and fibrous root reached the maximum under 450 kg/hm² potassium level.

Conclusion In the present experimental conditions, the potassium level of 450 kg/hm² was most beneficial to the growth and accumulation of saponins in two-year-old P. notoginseng.