To explore the response of nitrogen metabolism in Masson pine (Pinus massoniana) to high CO₂ concentrations, needles from one-year-old seedlings were used as materials to detect key enzyme activities, gene expression and different forms of nitrogen metabolites after CO₂ stress for different durations (0 h, 6 h, 12 h, 24 h). The results show that elevated CO₂ affected the efficiency of nitrogen metabolism in Masson pine needles, inhibiting the expression of key genes involved in nitrogen metabolism, including glutamate synthase (GOGAT), nitrite reductase (NiR), glutamine synthase (GS), nitrate reductase (NR) and glutamate dehydrogenase (GDH), and decreasing the activities of GOGAT, NiR, and GS. The decrease in enzyme activities and gene expression caused a decrease in different forms of nitrogen metabolites, including total nitrogen, ammonium, nitrite and specific amino acids. With prolonged stress, the nitrate content increased first and then decreased. In this study, the response pattern of nitrogen metabolism to CO₂ stress in Masson pine needles was described, which may aid future research on nitrogen utilization in Masson pine.

中文翻译：

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马尾松针氮代谢对CO2升高的响应

为了探讨马尾松（Masonon massoniana）氮代谢对高CO ₂浓度的响应，以一岁大幼苗的针叶为材料，检测CO ₂胁迫后关键酶活性，基因表达和不同形式的氮代谢产物。不同的持续时间（0小时，6小时，12小时，24小时）。结果表明，CO ₂升高影响了马尾松针中氮代谢的效率，抑制了涉及氮代谢的关键基因的表达，包括谷氨酸合酶（GOGAT），亚硝酸还原酶（NiR），谷氨酰胺合酶（GS），硝酸盐还原酶（NR）和谷氨酸脱氢酶（ GDH），并降低GOGAT，NiR和GS的活性。酶活性和基因表达的降低导致不同形式的氮代谢物（包括总氮，铵，亚硝酸盐和特定氨基酸）的减少。随着胁迫时间的延长，硝酸盐含量先升高然后降低。本研究描述了马尾松针中氮代谢对CO ₂胁迫的响应模式，这可能有助于马尾松中氮的利用研究。