Seasonal analyses of arbuscular mycorrhizae, nitrogen-fixing bacteria and growth performance of the salt marsh grass Spartina patens
Seasonal analyses of arbuscular mycorrhizae, nitrogen-fixing bacteria and growth performance of the salt marsh grass Spartina patens
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DOI：
10.1007/s11104-009-0197-5
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发表时间：
2010-05
期刊：
影响因子：
4.9
通讯作者：
Allana Welsh;D. Burke;E. Hamerlynck;D. Hahn
中科院分区：
文献类型：
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作者：
Allana Welsh;D. Burke;E. Hamerlynck;D. Hahn
在植物生长季节的关键时期，即营养生长、生殖和衰老的关键时期，研究了高盐沼泽植物Spartina patens根部丛枝菌根真菌(AMF)的季节变化、根际固氮菌的多样性和植物生长表现。AMF的定殖率在营养生长期间最高，在生长季节下降到与植物休眠时相同的水平。在观察到缺氧条件的沉积物和全身杀菌剂苯菌灵处理的植物中，AMF的定殖率在较低的深度减少。以ε为模板扩增的nifH基因片段的PCRRFLP检测到的固氮菌多样性在季节和处理间变化不大，但以nifH基因片段为模板扩增时，表现出较大的季节性变化。以DNA和cDNA为模板，对变形杆菌ε亚区固氮菌的nifH基因片段进行了DGGE分析，结果表明，nifH基因片段在季节和对处理的响应中发生了很大的变化。观察到一系列植物生长属性的季节性变化，并观察到不同处理之间的差异，与苯菌灵处理的植物相比，未处理的植物通常获得更高的值。这些差异在营养生长期间最为明显；然而，未处理和苯菌灵处理的植物之间的差异随着季节的推移而减小，并在开始衰老时消失。这项研究证明了AMF在ONS中的定植季节变化。在植物根区变形杆菌ε细分的固氮成员的群落结构中。植株生长表现有季节性变化，苯菌灵处理对植株生长有一定影响。
Seasonal variation of arbuscular mycorrhizal fungi (AMF) in roots of the high salt marsh plantSpartina patens, the diversity of nitrogen-fixing bacteria in the rhizosphere and plant growth performance was studied at key stages of the growing season coinciding with major plant phenological stages, i.e., vegetative growth, reproduction and senescence. AMF colonization was highest during vegetative growth, with values declining during the growing season to the same level seen at plant dormancy. AMF colonization was reduced at lower depths in the sediments where anoxic conditions were observed and in plants treated with the systemic fungicide Benomyl. Only small changes in diversity of nitrogen-fixing bacteria in general and more specifically of those belonging to the ε-subdivision of Proteobacteria were detected during the season or between treatments by PCR-RFLP ofnifH gene fragments with DNA as template for amplification; however, greater seasonal changes were displayed when cDNA was used as template for amplification as a proxy for gene expression and thus active bacteria. DGGE analyses ofnifH gene fragments representing nitrogen-fixing bacteria of the ε-subdivision of Proteobacteria using both using DNA and cDNA as template showed highly diverse profiles that changed during the season and in response to treatment. Seasonal changes were observed for a suite of plant growth attributes and differences were observed between treatments, with higher values generally obtained on non-treated plants compared to Benomyl-treated plants. These differences were most pronounced during vegetative growth; however, differences between non-treated and Benomyl-treated plants were reduced seasonally and disappeared by the onset of senescence. This study demonstrates seasonal changes in AMF colonization onS. patensand in the community structure of nitrogen-fixing members of the ε-subdivision of Proteobacteria in the plant root zone. Plant growth performance changed seasonally with some effects of Benomyl-treatment.