Metabolomics analysis of root exudates in southern subtropical pure and mixed stands

doi:10.17521/cjpe.2025.0047

Abstract

Abstract:

Aims As a crucial coupling agent linking plant roots, soil, and microorganisms, root exudates serve not only as an important vector for information transformation, but also as the core carrier for energy input, playing a significant role in shaping responses of plants to environmental changes. However, the effects of mixed-species on the metabolite compositions of root exudates remain unclear. Our objective is to explore the differences in metabolite compositions of root exudates between mixed stands and corresponding pure stands, and the implications on sustainable management of subtropical plantations.

Methods In this study, we used in-situ collection devices to sample root exudates of Pinus massoniana and Erythrophleum fordii in their pure and mixed (P. massoniana× E. fordii) stands in southern subtropial China. The metabolite compositions of root exudates of each species were analyzed using LC-MS/MS.

Important findings (1) The relative quantitative values of lipids, organic heterocyclic compounds, organic acids and organic oxygen compounds of root exudates of P. massoniana and E. fordii were significantly higher in pure stands than in mixed stands. (2) Comparative analysis of differential metabolites between pure and mixed forests, we revealed that P. massoniana had 208 differential metabolites, with glycerophospholipids exhibiting significant up-regulation in the P. massonianapure forest, and E. fordii had 106 differential metabolites, with p-Mentha-1,8-dien-7-ol, chavicol, isobutyric acid and diplodiatoxin exhibiting significant up-regulation in the E. fordiipure forest. (3) KEGG annotation and enrichment analysis showed that lipid metabolism pathways were significantly up-regulated in both P. massoniana and E. fordiipure forests compared to their mixed forest, and the lipid metabolism was correlated with plant defense strategies.

Key words: root exudate, metabolite composition, pure stand, mixed stand, southern subtropical China, Pinus massoniana, Erythrophleum fordii

XIA Qi, NIE Xiu-Qing, CHEN Yi-Qun, LIU Shi-Rong. Metabolomics analysis of root exudates in southern subtropical pure and mixed stands[J]. Chin J Plant Ecol, 2026, 50(1): 188-201.

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Figures/Tables 8

References 66

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指标 Indicator	马尾松纯林 Pinus massoniana stands	格木纯林 Erythrophleum fordii stands	马尾松×格木混交林 P. massoniana × E. fordii mixed stands
树种特性 Tree species properties	速生、针叶 Fast-growing, coniferous	固氮、阔叶 Nitrogen-fixing, broadleaf	速生、针叶(马尾松) 固氮、阔叶(格木) Fast-growing, coniferous (Pinus massoniana ) Nitrogen-fixing, broadleaf (Erythrophleum fordii)
林龄 Stand age (a)	22	22	20
生长阶段 Growth stage	近熟林 Near-mature	近熟林 Near-mature	近熟林 Near-mature
土壤类型 Soil type	赤红壤 Lateritic red soil	赤红壤 Lateritic red soil	赤红壤 Lateritic red soil
林分密度 Stand density (Ind.·hm^-2)	1 615 ± 115	1 633 ± 236	1 575 ± 148
胸径 Diameter at breast height (cm)	17.53 ± 3.40	13.52 ± 3.69	17.37 ± 3.12
树高 Tree height (m)	15.94 ± 1.12	13.67 ± 2.19	15.42 ± 1.11
海拔 Altitude (m)	274 ± 6	246 ± 4	216 ± 4
坡度 Slope (°)	12 ± 2	13 ± 1	10 ± 2

指标 Indicator	马尾松纯林 Pinus massoniana stands	格木纯林 Erythrophleum fordii stands	马尾松×格木混交林 P. massoniana × E. fordii mixed stands
树种特性 Tree species properties	速生、针叶 Fast-growing, coniferous	固氮、阔叶 Nitrogen-fixing, broadleaf	速生、针叶(马尾松) 固氮、阔叶(格木) Fast-growing, coniferous (Pinus massoniana ) Nitrogen-fixing, broadleaf (Erythrophleum fordii)
林龄 Stand age (a)	22	22	20
生长阶段 Growth stage	近熟林 Near-mature	近熟林 Near-mature	近熟林 Near-mature
土壤类型 Soil type	赤红壤 Lateritic red soil	赤红壤 Lateritic red soil	赤红壤 Lateritic red soil
林分密度 Stand density (Ind.·hm^-2)	1 615 ± 115	1 633 ± 236	1 575 ± 148
胸径 Diameter at breast height (cm)	17.53 ± 3.40	13.52 ± 3.69	17.37 ± 3.12
树高 Tree height (m)	15.94 ± 1.12	13.67 ± 2.19	15.42 ± 1.11
海拔 Altitude (m)	274 ± 6	246 ± 4	216 ± 4
坡度 Slope (°)	12 ± 2	13 ± 1	10 ± 2

指标 Indicator	马尾松纯林 Pinus massoniana stands	格木纯林 Erythrophleum fordii stands	马尾松×格木混交林 P. massoniana × E. fordii mixed stands
pH	3.56 ± 0.02^b	3.68 ± 0.04^a	3.62 ± 0.03^a
含水量 Water content (%)	31.67 ± 1.74^a	30.46 ± 2.50^a	31.21 ± 1.29^a
容重 Bulk density (g·cm^-3)	1.26 ± 0.02^a	1.21 ± 0.03^a	1.28 ± 0.01^a
粉粒含量 Silt content (%)	20.30 ± 1.83^a	5.79 ± 0.76^b	16.73 ± 2.50^a
黏粒含量 Clay content (%)	25.48 ± 1.22^a	7.43 ± 0.79^b	21.95 ± 3.70^a
有机碳含量 Organic carbon content (g·kg^-1)	15.08 ± 1.11^b	21.06 ± 1.03^a	14.76 ± 0.43^b
全氮含量 Total nitrogen content (g·kg^-1)	1.33 ± 0.05^b	1.60 ± 0.07^a	1.50 ± 0.17^a
有效氮含量 Available nitrogen content (mg·kg^-1)	120.33 ± 9.85^a	139.79 ± 5.27^a	139.43 ± 3.09^a
全磷含量 Total phosphorus content (g·kg^-1)	0.22 ± 0.04^a	0.27 ± 0.03^a	0.30 ± 0.01^a
碳氮比 Ratio of carbon to nitrogen	11.40 ± 0.87^b	13.20 ± 0.62^a	10.09 ± 0.72^b
氮磷比 Ratio of nitrogen to phosphorus	6.59 ± 0.42^a	6.12 ± 0.66^ab	5.15 ± 0.18^b
微生物生物量碳含量 Microbial biomass carbon content (mg·kg^-1)	599.71 ± 73.98^b	1 526.31 ± 150.64^a	849.13 ± 43.81^b
微生物生物量氮含量 Microbial biomass nitrogen content (mg·kg^-1)	49.14 ± 5.66^c	140.25 ± 9.52^a	96.72 ± 3.25^b
微生物量碳氮比 Ratio of microbial biomass carbon to microbial biomass nitrogen	12.21 ± 0.44^a	10.80 ± 0.40^a	8.81 ± 0.35^b

指标 Indicator	马尾松纯林 Pinus massoniana stands	格木纯林 Erythrophleum fordii stands	马尾松×格木混交林 P. massoniana × E. fordii mixed stands
pH	3.56 ± 0.02^b	3.68 ± 0.04^a	3.62 ± 0.03^a
含水量 Water content (%)	31.67 ± 1.74^a	30.46 ± 2.50^a	31.21 ± 1.29^a
容重 Bulk density (g·cm^-3)	1.26 ± 0.02^a	1.21 ± 0.03^a	1.28 ± 0.01^a
粉粒含量 Silt content (%)	20.30 ± 1.83^a	5.79 ± 0.76^b	16.73 ± 2.50^a
黏粒含量 Clay content (%)	25.48 ± 1.22^a	7.43 ± 0.79^b	21.95 ± 3.70^a
有机碳含量 Organic carbon content (g·kg^-1)	15.08 ± 1.11^b	21.06 ± 1.03^a	14.76 ± 0.43^b
全氮含量 Total nitrogen content (g·kg^-1)	1.33 ± 0.05^b	1.60 ± 0.07^a	1.50 ± 0.17^a
有效氮含量 Available nitrogen content (mg·kg^-1)	120.33 ± 9.85^a	139.79 ± 5.27^a	139.43 ± 3.09^a
全磷含量 Total phosphorus content (g·kg^-1)	0.22 ± 0.04^a	0.27 ± 0.03^a	0.30 ± 0.01^a
碳氮比 Ratio of carbon to nitrogen	11.40 ± 0.87^b	13.20 ± 0.62^a	10.09 ± 0.72^b
氮磷比 Ratio of nitrogen to phosphorus	6.59 ± 0.42^a	6.12 ± 0.66^ab	5.15 ± 0.18^b
微生物生物量碳含量 Microbial biomass carbon content (mg·kg^-1)	599.71 ± 73.98^b	1 526.31 ± 150.64^a	849.13 ± 43.81^b
微生物生物量氮含量 Microbial biomass nitrogen content (mg·kg^-1)	49.14 ± 5.66^c	140.25 ± 9.52^a	96.72 ± 3.25^b
微生物量碳氮比 Ratio of microbial biomass carbon to microbial biomass nitrogen	12.21 ± 0.44^a	10.80 ± 0.40^a	8.81 ± 0.35^b

差异代谢物状态 Differential metabolite status	马尾松纯林-混交林对比 P. massoniana pure-mixed stand comparison	格木纯林-混交林对比 E. fordii pure-mixed stand comparison
上调 Up-regulated	199	103
下调 Down-regulated	9	3