Pregitzer Kurt S, Hendrick Ronald L, Fogel Robert
Department of Forestry, Michigan State University, East Lansing, MI, 48824, USA.
Herbarium & Department of Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
New Phytol. 1993 Nov;125(3):575-580. doi: 10.1111/j.1469-8137.1993.tb03905.x.
Fine root demography was quantified in response to patches of increased water and nitrogen availability in a natural, second-growth, mixed hardwood forest in northern Michigan, USA. As expected, the addition of water and water plus nitrogen resulted in a significant overall increase in the production of new fine roots. New root production was much greater in response to water plus nitrogen when compared with water alone, and the duration of new root production was related to the length of resource addition in the water plus nitrogen treatments; the average difference in new root length between the 20 vs. 40 d additions of water plus nitrogen amounted to almost 600%. Roots produced in response to the additions of water and water plus nitrogen lived longer than roots in the control treatments. Thus, additions of water and water plus nitrogen influenced both the proliferation of new roots and their longevity, with both proliferation and longevity related to the type and duration of resource supply. Results suggest that root longevity and mortality may be plastic in response to changes in soil resource availability, as is well known for root proliferation.
在美国密歇根州北部一片天然的、次生的、硬木混交林中，对细根种群统计学进行了量化研究，以了解其对水分和氮素有效性增加斑块的响应。正如预期的那样，添加水分以及水分加氮导致新细根产量总体显著增加。与单独添加水分相比，添加水分加氮时新根产量要高得多，并且新根生产的持续时间与水分加氮处理中资源添加的时长有关；在添加水分加氮20天与40天的情况下，新根长度的平均差异几乎达到600%。因添加水分和水分加氮而产生的根比对照处理中的根存活时间更长。因此，添加水分和水分加氮既影响新根的增殖，也影响其寿命，增殖和寿命都与资源供应的类型和持续时间有关。结果表明，根的寿命和死亡率可能会因土壤资源有效性的变化而具有可塑性，这与根的增殖情况一样广为人知。
