Abstract The intimate connection between roots and soil particles is a prerequisite for the continuous flow of water and nutrients from soil to trees, and carbon flow from roots to the rhizosphere. The soil-root interface has been studied in multiple laboratory and greenhouse experiments. Yet its multiple roles and their differential contributions to tree health have rarely been experimentally studied on mature trees in the field. We took advantage of mature olive tree transplanting to test the physiological effects of breakage of the soil-root interface in situ. Eight olive trees were monitored following transplantation into a site located 4 km from their native site, along two years. Additional eight trees were monitored simultaneously at the native site, as control. To decrease mortality risk, transplanted trees were heavily pruned before transplanting, and were irrigated and fertilized in their new site. Transplanted trees had ~50% lower rates of leaf photosynthesis and transpiration; ~80% lower root starch content; and ~30% higher loss of xylem conductivity, than native trees. Leaf water potential (LWP) was similar across trees, becoming more negative in the transplanted trees only in the second year following transplanting. While starch content and xylem conductivity recovered in the second year, leaf gas exchange and LWP remained significantly lower than in native trees. Soil P and K were higher under transplanted trees that remained stressed than under trees that recovered. Breakage of the soil-root interface caused a multi-system stress to trees. The lack of persistent LWP response might indicate that loss of hydraulic conductivity was driven by root, rather than aboveground, embolisms. Degradation of starch in the roots indicates an increase in belowground sinks. In the long run, recovery of starch content means no carbon limitation; yet the prevailing effects on leaf activities suggest a long-term stress unrelated with water or carbon supply.

中文翻译：

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成熟树移栽的生理效应表征了土壤-根系界面在田间的作用

摘要 根系与土壤颗粒之间的密切联系是水和养分从土壤向树木持续流动、碳从根部向根际流动的前提。已经在多个实验室和温室实验中研究了土壤-根系界面。然而，它的多重作用及其对树木健康的不同贡献很少在该领域的成熟树木上进行实验研究。我们利用成熟的橄榄树移植来原位测试土壤-根系界面断裂的生理效应。八棵橄榄树在移植到距其原产地 4 公里的地点后，两年内进行了监测。在原生地点同时监测另外八棵树作为对照。为了降低死亡风险，移植的树木在移植前被大量修剪，并在新地点进行灌溉和施肥。移植的树木的叶子光合作用和蒸腾速率降低了约 50%；根淀粉含量降低约 80%；木质部电导率损失比原生树木高约 30%。树木之间的叶水势 (LWP) 相似，仅在移植后的第二年才在移植的树木中变得更负。虽然淀粉含量和木质部电导率在第二年恢复，但叶片气体交换和 LWP 仍显着低于原生树木。保持压力的移植树木下的土壤 P 和 K 高于恢复的树木下。土壤-根系界面的断裂对树木造成多系统应力。缺乏持续的 LWP 响应可能表明导水率的损失是由根部而不是地上的栓塞引起的。根中淀粉的降解表明地下汇增加。从长远来看，淀粉含量的恢复意味着没有碳限制；然而，对叶子活动的普遍影响表明长期压力与水或碳供应无关。