Root proliferation, soil fauna and plant nitrogen capture from nutrient-rich patches in soil
Root proliferation, soil fauna and plant nitrogen capture from nutrient-rich patches in soil
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DOI：
10.1046/j.1469-8137.1998.00216.x
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发表时间：
1998-07-01
期刊：
影响因子：
9.4
通讯作者：
Fitter, AH
中科院分区：
文献类型：
--
作者：
Hodge, A;Stewart, J;Fitter, AH
我们研究了植物根系，原生动物和线虫之间的相互作用后，添加含有无机或有机氮的补丁，以确定根增殖是否可以解释N的植物从补丁的捕获。分解的N-15/C-13，双标记，有机补丁在植物根的情况下也进行了检查。在腐解斑块中，C-13和N-15的残留量随时间变化，均呈下降趋势。线虫数量增加。然而，原生动物的生物量和无机氮（NO3-和NH 4+）的可用性没有显着改变的补丁分解的进展。以NH_4NO_3溶液作为无机氮补片，对多年生黑麦草种子根主轴第一侧根进行补施。与对照相比，添加16 d后幼苗的根系生长没有影响。原生动物生物量增加。原生动物对数生物量与培养液中NO3-浓度呈显著正相关（P < 0.05）。使用五种不同的草种（高羊茅L.，草苔草，草地早熟禾，鸭茅和L. perenne）。植物总生物量被有机斑块显著抑制（P < 0.05）。植物氮含量降低时，有机补丁是存在的，但氮浓度更大。根一般缓慢的补丁内增殖，但有一个显着的（P < 0.05）种×补丁内的根长在收获时，在2厘米带低于它的交互作用。然而，N-15捕获的植物是不相关的平均根长持续时间。所有物种捕获的N-15（C。3-5%），作为在有机块中添加的初始N-15的百分比。同样，从斑块中捕获的总N的百分比与斑块内根重的比例无关。然而，从有机斑块中捕获的N占植物总N的百分比的分数在物种之间确实存在差异。最初添加的大量（> 62%）N-15在收获时保留在贴片中。更少（C。13- 21%的C-13保留在贴片中。原生动物生物量和线虫数量在有机斑块中显著增加（P < 0.05），但两者之间的相关性不显著。在无机氮的研究，对数原生动物生物量和NO3-浓度在土壤中的关系是显着的积极。我们的结论是，当生长在单一栽培，植物的N捕获从一个有机补丁是不是一个简单的功能根增殖。外部因素，而不是植物属性，在控制斑块开发更重要。
We investigated interactions between plant roots, protozoa and nematodes after addition of patches containing inorganic or organic nitrogen in order to determine whether root proliferation could explain the capture of N by the plant from the patch. Decomposition of a N-15/C-13, dual-labelled, organic patch in the absence of plant roots was also examined. In the decomposing patch the amounts of C-13 and N-15 remaining co-varied and both declined with time. Nematode numbers increased. However, protozoan biomass and inorganic N (NO3- and NH4+) availability did not significantly alter as decomposition of the patch progressed. Addition of inorganic N patches, as NH4NO3 solutions, to the first lateral to emerge from the main seminal root axis of Lolium perenne L. seedlings had no effect on root growth compared with controls 16 d after addition. Protozoan biomass increased. Furthermore, log protozoan biomass and NO3- concentrations of the growth medium were significantly (P < 0.05) and positively related. Plant response (i.e. biomass production, N capture and root length) to an added organic patch was examined using five different grass species (Festuca arundinacea L., Phleum pratense L., Poa pratensis L., Dactylis glomevata L,. and L. perenne). Total plant biomass was significantly (P < 0.05) repressed by an organic patch. Plant N content was reduced when an organic patch was present but N concentrations were greater. Roots were generally slow to proliferate within the patch but there was a significant (P < 0.05) species x patch interaction for root length within the patch at harvest and in the 2-cm band below it. However, N-15 capture by the plants was not related to mean root length duration. All species captured similar amounts of N-15 (C. 3-5 %) at harvest as a percentage of the initial N-15 added in the organic patch. Similarly, the percentage of the total N captured from the patch was not related to the proportion of the root weight within the patch. The fraction of the captured N from the organic patch as a percentage of the plants' total N, however, did differ among species. Substantial amounts (> 62 %) of the N-15 initially added remained in the patch at harvest. Much less (c. 13-21 %) C-13 remained in the patch. Protozoan biomass and nematode numbers increased significantly (P < 0.05) in the organic patch, although the relationship between the two groups was not significant. As in the inorganic N study, the relationship between log protozoan biomass and NO3- concentrations in the soil was significantly positive. We conclude that, when grown in monoculture, plants' N capture from an organic patch is not a simple function of root proliferation. External factors, not plant attributes, are more important in controlling patch exploitation.