...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Soil Biology & Biochemistry >Rhizosphere priming of soil organic matter by bacterial groups in a grassland soil
【24h】

Rhizosphere priming of soil organic matter by bacterial groups in a grassland soil

机译：草原土壤中细菌群对土壤有机质的根际激发

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Plants often impact the rate of native soil organic matter turnover through root interactions with soil organisms; however the role of root-microbial interactions in mediation of the "priming effect" is not well understood. We examined the effects of living plant roots and N fertilization on belowground C dynamics in a California annual grassland soil (Haploxeralf) during a two-year greenhouse study. The fate of [super]13C-labeled belowground C (roots and organic matter) was followed under planted (Avena barbata) and unplanted conditions, and with and without supplemental N (20 kg N ha[super]-1 season[super]-1) over two periods of plant growth, each followed by a dry, fallow period of 120 d. Turnover of belowground [super]13C SOM was followed using [super]13C-phospholipid fatty acid (PLFA) biomarkers. Living roots increased the turnover and loss of belowground [super]13C compared with unplanted soils. Planted soils had 20% less belowground [super]13C present than in unplanted soils after 2 cycles of planting and fallow. After 2 treatment cycles, unlabeled soil C was 4.8% higher in planted soils than unplanted. The addition of N to soils decreased the turnover of enriched belowground [super]13C during the first treatment season in both planted and unplanted soils, however no effect of N was observed thereafter. Our findings suggest that A. barbata may increase soil C levels over time because root and exudate C inputs are significant, but that increase will be moderated by an overall faster C mineralization rate of belowground C. N addition may slow soil C losses; however, the effect was minor and transient in this system. The labeled root-derived [super]13C was initially recovered in gram negative (highest enrichment), gram positive, and fungal biomarkers. With successive growing seasons, the labeled C in the gram negative and fungal markers declined, while gram positive markers continued to accumulate labeled belowground C. The rhizosphere of A. barbata shifted the microbial community composition, resulting in greater abundances of gram negative markers and lower abundances of gram positive, actinobacteria and cyclopropyl PLFA markers compared to unplanted soil. However, the longer-term utilization of labeled belowground C by gram positive bacteria was enhanced in the rhizosphere microbial community compared with unplanted soils. We suggest that the activities of gram positive bacteria may be major controllers of multi-year rhizosphere-related priming of SOM decomposition.
机译：植物通常通过与土壤生物的根系相互作用来影响天然土壤有机质的转化率。然而，根与微生物相互作用在“启动效应”的介导中的作用尚不十分清楚。在为期两年的温室研究中，我们检查了加利福尼亚州一年生草地土壤（Haploxeralf）中植物的根系和氮肥对地下C动态的影响。在种植（Avena barbata）和未种植的条件下，在有和没有补充氮（20 kg N ha-1季节）的情况下，跟踪13C标记的地下C（根和有机物）的命运。 1）在植物生长的两个阶段中，每个阶段之后是120 d的干燥休耕期。使用超13 C-磷脂脂肪酸（PLFA）生物标记物跟踪地下超13 C SOM的营业额。与未种植的土壤相比，活根增加了地下13C的周转和损失。经过2个种植和休耕周期，种植土壤比未种植土壤的地下13 C含量低20％。在2个处理周期后，种植土壤中的未标记土壤C比未种植土壤高4.8％。在种植和未种植的土壤中，在第一个处理季节，向土壤中添加氮都会降低富集地下13 C的周转率，但是此后未观察到氮的影响。我们的发现表明，由于根和渗出碳的输入量很大，半枝曲霉可能随时间增加土壤碳水平，但地下C的整体C矿化速率总体加快将抑制这种增加。但是，此系统的影响很小且短暂。最初以革兰氏阴性（最高富集），革兰氏阳性和真菌生物标记物回收了标记的根来源的super 13C。随着连续的生长季节，革兰氏阴性标记和真菌标记中的标记C下降，而革兰氏阳性标记继续在地下标记C积累。半枝叶甲的根际移动了微生物群落组成，导致革兰氏阴性标记的丰度更高而较低。与未种植的土壤相比，有大量革兰氏阳性，放线菌和环丙基PLFA标记。然而，与未种植的土壤相比，在根际微生物群落中，革兰氏阳性菌对标记的地下碳的长期利用得到了增强。我们建议革兰氏阳性细菌的活性可能是多年根际相关SOM分解引发的主要控制者。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号