Short-term effects of defoliation on the soil microbial community associated with two contrasting Lolium perenne cultivars
Short-term effects of defoliation on the soil microbial community associated with two contrasting Lolium perenne cultivars
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DOI：
10.1016/j.soilbio.2003.11.001
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发表时间：
2004-03
影响因子：
9.7
通讯作者：
Lynne M. Macdonald;E. Paterson;Lorna A. Dawson;A.James S. McDonald
中科院分区：
文献类型：
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作者：
Lynne M. Macdonald;E. Paterson;Lorna A. Dawson;A.James S. McDonald
在土壤微生物群落(SMC)方面，对落叶和土壤改良的响应在很大程度上忽略了种内差异。通过对两个多年生黑麦草品种贮藏量积累能力的比较，评价了去叶和土壤肥料改良剂对黑麦草贮藏量结构的影响。植物对落叶的反应是品种特有的，并取决于土壤的养分改良剂。结果表明，与高碳水化合物品种(AberDove)相比，低碳水化合物积累品种(S23)在改良(IMP)而不是在未改良(UNI)土壤中生长时，改变植物生物量分配的能力更强。尽管植物生长参数有明显差异，但活性微生物生物量(总磷脂脂肪酸)的大小(总磷脂脂肪酸313.8nmolg−1土壤±33.9nmolg)或磷脂脂肪酸标志组的比例没有发现处理效果。与非去叶(ND)处理相比，去叶(D)处理的Biolog唯一碳源利用谱(SCSUP)的平均颜色发展(AWCD)较低，这可能表明由于较低的根非结构性碳水化合物(NSC)浓度，在去叶后一周的根分泌物较少。在细菌群落内，UNI土壤中PLFAs的环丙基/前体比率和16：1w7的反式/顺式比率比IMP土壤处理低，表明无论黑麦草品种，UNI土壤的生理应激程度都较低。PLFA分析表明，土壤处理与品种和落叶有很强的交互作用。在IMP土壤中，SMCs区分不同的品种，而去叶对其影响不大。相反，在Uni土壤中，落叶导致与两个品种相关的SMC共同移动，导致整体群落结构的趋同。根冠比(47.6%)与根冠比(47.6%)相关最大(P<；0.001)，说明不同处理间品种C分配的差异对确定根际微生物群落有重要影响。
Intra-species variation in response to defoliation and soil amendment has been largely neglected in terms of the soil microbial community (SMC). The influence of defoliation and soil fertiliser amendment on the structure of the SMC was assessed with two Lolium perenne cultivars contrasting in ability to accumulate storage reserves. Plant response to defoliation was cultivar specific and depended on the nutrient amendment of the soil. Results suggested a greater ability to alter plant biomass allocation in the low carbohydrate accumulating cultivar (S23) compared to the high carbohydrate cultivar (AberDove) when grown in improved (IMP), but not in unimproved (UNI), soil. Although differences in plant growth parameters were evident, no treatment effects were detected in the size of the active microbial biomass (total phospholipid fatty acid (PLFA) 313.8nmolg−1soil±33.9) or proportions of PLFA signature groups. A lower average well colour development (AWCD) of Biolog sole carbon source utilisation profiles (SCSUPs) in defoliated (D) compared to non-defoliated (ND) treatments may be indicative of lower root exudation 1 week following defoliation, as a consequence of lower root non-structural carbohydrate (NSC) concentrations. Within the bacterial community the lower cyclopropyl-to-precursor ratio of PLFAs, and the trans/cis ratio of 16:1w7, in UNI relative to IMP soil treatments indicates lower physiological stress in UNI soils regardless of L. perenne cultivar. Discrimination of broad scale SMC structure, measured by PLFA analysis, revealed that soil treatment interacted strongly with cultivar and defoliation. In IMP soils the SMCs discriminated between cultivars while defoliation had little effect. Conversely, in UNI soils defoliation caused a common shift in the SMC associated with both cultivars, causing convergence of overall community structure. Separation of SMC structure along the primary canonical axis correlated most strongly (P<0.001) with root:shoot ratio (47.6%), confirming that differences in cultivar C-partitioning between treatments were influential in defining the rhizosphere microbial community.