Effects of Drought Stress on Resistance Physiology, Total Alkaloids, and Total Polysaccharides of Pinellia ternate

In this study, a potting water control experiment was conducted indoors. Using Pinellia ternata from five different producing areas (Leshan, Sichuan; Zhangjiakou, Hebei; Heze, Shandong; Yongzhou, Hunan; Shangluo, Shaanxi) as experimental materials, we set up three treatment groups with different soil water contents to investigate the effects of drought stress on the growth, physiology, contents of total alkaloids and total polysaccharides of Pinellia ternata. The results showed that stem tuber weight, leaf net photosynthetic rate, stomatal conductance, transpiration rate, Electron transport rate (ETR), Photochemical quenching coefficient (qP), Relative water content (RWC) and Peroxidase (POD) were gnificantly decreased. The contents of Soluble Protein (SP) and Proline (PRO) were significantly increased, Catalase (CAT) and Glutathione (GSH) increased first and then decreased.Under the treatment of regular watering for 20 days followed by a 10-day period without watering, the contents of total alkaloids and total polysaccharides in certain Pinellia ternata germplasms increased significantly. First water normally for 20 days and then stop watering and grow for 10 days, the total alkaloid content and total polysaccharide content of some Pinellia ternata germplasm were significantly increased. Principal component analysis showed that ground diameter, transpiration rate, GSH content, Chlorophyll b content and intercellular CO2 concentration played a leading role in drought resistance evaluation of Pinellia ternata. Correlation analysis showed that GSH content was significantly negatively correlated with POD activity (P < 0.05), SP was significantly negatively correlated with SP (P < 0.01), and total alkaloid content was significantly positively correlated with GSH content (P < 0.01), alkaloids and total polysaccharides among the five Pinellia ternata species (P < 0.05). It can be concluded that there are significant differences in resistance physiological indicators, total alkaloids and total polysaccharides among the five Pinellia ternata species (P < 0.05), the underground biomass and leaf photosynthesis ability of Pinellia ternata are significantly reduced by drought stress. To some extent, drought stress promotes the accumulation of total alkaloids and total polysaccharides in P. ternata, except for the P. ternata from Zhangjiakou, the contents of total alkaloids in P. ternata from the other producing areas increased significantly under drought stress. The contents of total polysaccharides in P. ternata from Leshan, Yongzhou and Heze increased to varying degrees under the influence of drought stress.