Effects of lime and oxalic acid on antioxidant enzymes and active components of Panax notoginseng under cadmium stress

Abstract

Cadmium (Cd) pollution poses potential safety risks for Panax notoginseng cultivation, a medicinal plant in Yunnan. Under exogenous Cd stress, field experiments were conducted to understand the effects of lime (0, 750, 2250 and 3750 kg hm−2) applied and oxalic acid (0, 0.1 and 0.2 mol L−1) leaves sprayed on Cd accumulation, antioxidant system and medicinal components of P. notoginseng. The results showed that Lime and foliar spray of oxalic acid were able to elevate Ca2+ and alleviate Cd2+ toxicity in P. notoginseng under Cd stress. The addition of lime and oxalic acid increased the activities of antioxidant enzymes and alters osmoregulator metabolism. The most significant increase in CAT activities increased by 2.77 folds. And the highest increase of SOD activities was 1.78 folds under the application of oxalic acid. While MDA content decreased by 58.38%. There were very significant correlation with soluble sugar, free amino acid, proline and soluble protein. Lime and oxalic acid were able to increase calcium ions (Ca2+), decrease Cd content and improve the stress resistance of P. notoginseng, while increasing the production of total saponins and flavonoids. Cd content were the lowest, 68.57% lower than controls, and met the standard value (Cd ≤ 0.5 mg kg−1, GB/T 19086-2008). The proportion of SPN was 7.73%, which reached the highest level of all treatments, the flavonoids content increased significantly by 21.74%, which reached the medicinal standard value and optimal yield.

Exogenous leucine alleviates heat stress and improves saponin synthesis in Panax notoginseng by improving antioxidant capacity and maintaining metabolic homeostasis

“…Pan et al. (2015) reported that the addition of oxalate could improve the accumulation of saponins in Psammosilene tunicoides cell suspensions, and Li et al. (2022a) reported that the application of oxalate could improve the accumulation of PNSs under Cd stress.…”

“…Moreover, the oxalate content in the stems and roots of P. notoginseng increased significantly after leucine application (Figure 4). Pan et al (2015) reported that the addition of oxalate could improve the accumulation of saponins in Psammosilene tunicoides cell suspensions, and Li et al (2022a) reported that the application of oxalate could improve the accumulation of PNSs under Cd stress. It is thus suggested that the increase in oxalate content after leucine application may also contribute to the accumulation of PNSs.…”

Crater–Spectrum Feature Fusion Method for Panax notoginseng Cadmium Detection Using Laser-Induced Breakdown Spectroscopy

“…The efficacy of P. notoginseng is affected by toxic metal contamination, a topic of increasing interest because of the abundance of mineral resources in P. notoginseng-cultivated soil. Cadmium (Cd) absorption and enrichment in P. notoginseng is relatively strong, and Cd is more easily transferred to the ground [3]. Cd contamination not only reduces the yield of P. notoginseng and diminishes the accumulation of bioactive compounds [4], but it also poses risks to environmental pollution and human health [5].…”