Pharmaceutical College, Guangxi Medical University, Nanning, 530021, China.
Guangxi Key Laboratory of Medicinal Resources Protection and Genetic Improvement, Guangxi Botanical Garden of Medicinal Plants, Nanning, 530023, China.
Sci Rep. 2022 Mar 22;12(1):4906. doi: 10.1038/s41598-022-08971-x.
The effects of exogenous sucrose (Suc) concentrations (0, 0.5, 1, 5, 10 mmol L) on carbon (C) and nitrogen (N) metabolisms were investigated in a medicinal plant Andrographis paniculata (Chuanxinlian). Suc application with the concentration of 0.5-5 mmol L significantly promoted plant growth. In contrast, 10 mmol L Suc retarded plant growth and increased contents of anthocyanin and MDA and activity of SOD in comparison to 0.5-5 mmol L Suc. Suc application increased contents of leaf soluble sugar, reducing sugar and trerhalose, as well as isocitrate dehydrogenase (ICDH) activity, increasing supply of C-skeleton for N assimilation. However, total leaf N was peaked at 1 mmol L Suc, which was consistent with root activity, suggesting that exogenous Suc enhanced root N uptake. At 10 mmol L Suc, total leaf N and activities of glutamine synthase (GS), glutamate synthase (GOGAT), NADH-dependent glutamate dehydrogenase (NADH-GDH) and glutamic-pyruvic transaminase (GPT) were strongly reduced but NH concentration was significantly increased. The results revealed that exogenous Suc is an effective stimulant for A. paniculata plant growth. Low Suc concentration (e.g. 1 mmol L) increased supply of C-skeleton and promoted N uptake and assimilation in A. paniculata plant, whereas high Suc concentration (e.g. 10 mmol L) uncoupled C and N metabolisms, reduced N metabolism and induced plant senescence.
外源蔗糖（Suc）浓度（0、0.5、1、5、10 mmol/L）对药用植物穿心莲碳（C）和氮（N）代谢的影响。0.5-5 mmol/L 的 Suc 处理显著促进了植物生长。相比之下，10 mmol/L 的 Suc 处理会减缓植物生长，增加花色素苷和 MDA 的含量，以及 SOD 的活性，与 0.5-5 mmol/L 的 Suc 相比。Suc 处理增加了叶片可溶性糖、还原糖和海藻糖的含量，以及异柠檬酸脱氢酶（ICDH）的活性，为 N 同化提供了更多的 C 骨架。然而，总叶片 N 在 1 mmol/L Suc 时达到峰值，这与根活性一致，表明外源 Suc 增强了根对 N 的吸收。在 10 mmol/L Suc 时，总叶片 N 以及谷氨酰胺合成酶（GS）、谷氨酸合酶（GOGAT）、NADH 依赖性谷氨酸脱氢酶（NADH-GDH）和谷氨酸-丙酮酸转氨酶（GPT）的活性均显著降低，但 NH4+浓度显著增加。结果表明，外源 Suc 是穿心莲植物生长的有效刺激物。低 Suc 浓度（例如 1 mmol/L）增加了 C 骨架的供应，促进了穿心莲植物对 N 的吸收和同化，而高 Suc 浓度（例如 10 mmol/L）则使 C 和 N 代谢解偶联，降低了 N 代谢并诱导植物衰老。
