Nematodes and protozoa affect plants differently, depending on soil nutrient status

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• 作者：Lisa Bjø ; rnlund^a ; Manqiang Liu^a ; ^b ; Regin Rø ; nn^a ; Sø ; ren Christensen^a ; Flemming Ekelund^a ; ^{fekelund@bio.ku.dk}
• 关键词：Bacterial feeders ; Plant performance ; Protozoa ; Nematodes ; Microbial loop selective feeding
• 刊名：European Journal of Soil Biology
• 出版年：2012
• 期刊代码：43_11645563
• 类别：abs
• 出版时间：May-June, 2012
• 卷：50
• 期：Complete
• 页码：28-31
• 文件大小：369 K

摘要

We grew plants in soil amended with either finely ground (<0.2聽mm) or larger pieces (4聽脳聽5 mm²) of maize leaves. Finely ground material will be mineralized faster; hence nitrogen is released faster in the soil. We inoculated the soil with the plant growth inhibiting bacterium Arthrobacter BEM463, a relatively poor food source for bacterial feeders, and the plant growth promoter Sphingopyxis BEM760 which is a good food source. Protozoa and nematodes were introduced separately or in combination. In soil with larger maize leaf pieces (low turnover, slow nitrogen release), bacterial feeders generally increased plant nitrogen uptake and growth. In systems with finely ground material (high turnover, fast nitrogen release), plants hardly benefited from presence of grazers; bacterial mineralization activity alone probably provided enough N for the plants. The harmful Arthrobacter thrived better when grazed by protozoa than when grazed by nematodes, probably because the selective protozoa could avoid it, which resulted in reduced plant performance. We suggest that bacterial feeders generally increase plant performance when nutrients are limited. At high nutrient availability, however, bacterial feeders promote grazer resistant bacteria, and, if these bacteria are harmful to plants, the net effect of bacterial feeders on plant growth can be negative.