Properties of root exudates and rhizosphere sediment of Bruguiera gymnorrhiza (L.)
Properties of root exudates and rhizosphere sediment of Bruguiera gymnorrhiza (L.)
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DOI：
10.1007/s11368-016-1541-z
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发表时间：
2016
影响因子：
3.6
通讯作者：
Beibei Liu;Xinyu Liu;S. Huo;Xin Chen;Lin Wu;Miao Chen;K. Zhou;Qinfen Li;Lixu Peng
中科院分区：
文献类型：
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作者：
Beibei Liu;Xinyu Liu;S. Huo;Xin Chen;Lin Wu;Miao Chen;K. Zhou;Qinfen Li;Lixu Peng
目的根际环境在促进红树林沉积物中有机污染物的生物降解和植物修复过程中发挥着重要作用，但其作用机制尚不清楚。对木榄（Bruguiera gymnorrhiza（L.）采用气相色谱-质谱联用仪（GC-MS）和高效液相色谱（HPLC）分析了红树植物水培根分泌物、根际和非根际沉积物中的有机组分和低分子量有机酸。利用16 S rDNA基因分析技术研究了沉积物中细菌的群落结构和多样性。利用固体13 C核磁共振技术对沉积物有机碳结构进行了分析。进行了稳定碳同位素分析，以评估根分泌物和凋落物（根，茎，叶）沉积物organic matter.Results and discussionThe有机组分中的红树林根分泌物收集从水培溶液沉积物，包括烃，酯，酚，和芳香在根际和非根际沉积物的贡献。但根际和非根际沉积物中各组分的含量及优势组分的含量存在差异。根际沉积物中有机碳、营养元素、阳离子交换量、微生物密度、酶活性和细菌多样性均高于非根际沉积物。凋落物是根际沉积物的主要有机质来源，但根际沉积物也从根系分泌物中吸收了较多的活性有机质。在根际沉积物中，大于1 mm的大团聚体所占比例和物理结构的稳定性均高于非根际沉积物。此外，大团聚体的微生物密度和细菌多样性高于中团聚体（0.25 ~ 1 mm）和微团聚体（<0.25 mm）。结论由于根系分泌物的输入，根际沉积物具有与非根际沉积物不同的化学、物理和微生物性质。根际沉积物的主要特征是有机质含量高、物理结构稳定、微生物活性高。对红树林根际效应的全面认识，对于进一步研究红树林促进有机污染物的生物降解和植物修复具有重要意义。
PurposeThe rhizosphere plays an important role in promoting the biodegradation and phytoremediation processes of organic pollutants in mangrove sediments; however, the mechanisms behind this interaction remain little understood. We analyzed the properties of root exudates and rhizosphere sediment ofBruguiera gymnorrhiza(L.) to provide basic information about the rhizosphere effects of mangroves.Materials and methodsWe analyzed the organic components and the low-molecular-weight organic acids in root exudates extracted from hydroponic culture solution, and the rhizosphere and non-rhizosphere sediments using gas chromatography-mass spectrometer and high-performance liquid chromatography. A 16S rDNA gene analysis was performed to investigate the bacterial community and diversity of sediments. The sediment organic carbon structures were analyzed using solid-state13C nuclear magnetic resonance. A stable carbon isotopic analysis was conducted to assess the contribution of root exudates and litter (root, stem, and leaf) to sediment organic matter.Results and discussionThe organic components in the mangrove root exudates were collected from the hydroponic culture solution sediments and included hydrocarbons, esters, phenols, and aromas in both the rhizosphere and non-rhizosphere sediments. However, the content of each component and the dominant components were different between the rhizosphere and non-rhizosphere sediments. The rhizosphere sediment showed a higher level of organic carbon, nutrient elements, cation exchange capacity, microorganism density, enzyme activities, and bacterial diversity than the non-rhizosphere sediment. Litter is the main organic matter resource of the rhizosphere sediment; however, the rhizosphere sediment also received more labile organic matters from root exudates. In the rhizosphere sediment, the percentage of macroaggregates (>1 mm) and the stability of the physical structure were higher than those of the non-rhizosphere sediment. In addition, the microorganism density and bacterial diversity of macroaggregates was higher than those of mesoaggregates (0.25–1 mm) and microaggregates (<0.25 mm).ConclusionsAs a result of the input of root exudates, the rhizosphere sediment had different chemical, physical, and microbial properties from the non-rhizosphere sediment. The predominant properties of the rhizosphere sediment were high content of organic matters, stable physical structure, and high microbial activity. This comprehensive understanding of the rhizosphere effects of mangroves is crucial for further studying of the promoted biodegradation and phytoremediation of organic pollutants in this special system.