Lv Xiaofei, Hao Jiangtao, Zhao Yumeng, Li Chaochan, Quan Wenxuan
Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, China.
Metabolites. 2023 Jan 12;13(1):119. doi: 10.3390/metabo13010119.
Low-molecular-weight organic acids (LMWOAs) are widely distributed in forests. Fresh leaves, litter, humus, and the topsoil layer of representative Rhododendron delavayi (RD), Rhododendron agastum (RA), and Rhododendron irroratum (RI) in the Baili Rhododendron National Forest Park were sampled to explore their seasonal changes. The contents of oxalic, tartaric, malic, citric, acetic, lactic, succinic, and formic acids in samples from different seasons were determined by high-performance liquid chromatography. The results showed that the composition and content of the LMWOAs in the fresh leaves, litter, humus, and topsoil layer of the rhododendrons were affected by the tree species, samples, and season. The main LMWOA was oxalic acid (the average content in the samples was 195.31 µg/g), followed by malic acid (the average content in the samples was 68.55 µg/g) and tartaric acid (the average content in the samples was 59.82 µg/g). Succinic acid had the lowest content; the average content in the samples was 18.40 µg/g. The LMWOAs of the RD were the highest (the average content in the samples was 517.42 µg/g), and the LMWOAs of the RI were the lowest (the average content in the samples was 445.18 µg/g). The LMWOAs in the three rhododendron forests were in the order of fresh leaves > litter > humus > soil layers. This study showed the seasonal distribution characteristics of LMWOAs in three evergreen broadleaf rhododendron forests, and the results provide a reference for ecosystem management and the protection of wild rhododendron forests.
低分子量有机酸（LMWOAs）广泛分布于森林中。对白里杜鹃国家森林公园中代表性的马缨杜鹃（RD）、迷人杜鹃（RA）和露珠杜鹃（RI）的新鲜叶片、凋落物、腐殖质及表层土壤进行采样，以探究其季节变化。采用高效液相色谱法测定不同季节样品中草酸、酒石酸、苹果酸、柠檬酸、乙酸、乳酸、琥珀酸和甲酸的含量。结果表明，杜鹃新鲜叶片、凋落物、腐殖质及表层土壤中LMWOAs的组成和含量受树种、样品及季节的影响。主要的LMWOA为草酸（样品中平均含量为195.31µg/g），其次是苹果酸（样品中平均含量为68.55µg/g）和酒石酸（样品中平均含量为59.82µg/g）。琥珀酸含量最低，样品中平均含量为18.40µg/g。马缨杜鹃的LMWOAs最高（样品中平均含量为517.42µg/g），露珠杜鹃的LMWOAs最低（样品中平均含量为445.18µg/g）。三种杜鹃林的LMWOAs含量顺序为新鲜叶片＞凋落物＞腐殖质＞土壤层。本研究揭示了三种常绿阔叶杜鹃林LMWOAs的季节分布特征，研究结果为生态系统管理和野生杜鹃林保护提供了参考。
