College of Ecological Technology and Engineering, Shanghai Institute of Technology, 100 Haiquan Road, Shanghai 201418, China.
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 4888 Shengbei Street, Changchun 130102, China.
Tree Physiol. 2024 Nov 5;44(11). doi: 10.1093/treephys/tpae129.
Coating high concentrations of copper (Cu) on the inner wall of containers can efficiently inhibit root entanglement of container-grown seedlings. However, how the protective and defensive responses of roots maintain root structure and function during Cu-root pruning is still unclear. Here, Duranta erecta L. seedlings were planted in the containers coated with 40 (T1), 80 (T2), 100 (T3), 120 (T4), 140 (T5) and 160 (T6) g L-1 Cu(OH)2 with containers without Cu(OH)2 as the control. Although T5 and T6 produced the best inhibitory effect on root entanglement, root anatomy structure was damaged. T1 and T2 not only failed to completely control root circling, but also led to decreased root activity and stunted growth. Cu(OH)2 treatments significantly increased lignin concentration of roots with the highest values at T3 and T4. Compared with T3, seedlings at T4 had higher height, biomass and root activity, and no significant root entanglement. Excessive Cu accumulation in Cu(OH)2 treatments changed the absorption of other mineral nutrients and their allocation in the roots, stems and leaves. Overall, Ca was decreased while Mg, Mn, Fe and K were increased, especially K and Mn at T4 which is related to defense capacity. The results indicate that there is a Cu threshold to balance root entanglement control, defense capacity and nutrient uptake function under excessive Cu for container-grown D. erecta seedlings.
在容器内壁涂覆高浓度的铜（Cu）可以有效地抑制容器苗的根系缠绕。然而，在 Cu 修剪根的过程中，根系如何维持其结构和功能的保护和防御反应仍不清楚。本研究采用 Duranta erecta L. 幼苗种植在涂覆有 40（T1）、80（T2）、100（T3）、120（T4）、140（T5）和 160（T6）g L-1 Cu（OH）2 的容器中，以未涂覆 Cu（OH）2 的容器作为对照。尽管 T5 和 T6 对根系缠绕的抑制效果最好，但根解剖结构受到了破坏。T1 和 T2 不仅未能完全控制根缠绕，还导致根活力降低和生长受阻。Cu（OH）2 处理显著增加了根的木质素浓度，在 T3 和 T4 时达到最高值。与 T3 相比，T4 下的幼苗具有更高的高度、生物量和根活力，且没有明显的根系缠绕。Cu（OH）2 处理中过量的 Cu 积累改变了其他矿质养分的吸收及其在根、茎和叶中的分配。总的来说，Ca 减少，而 Mg、Mn、Fe 和 K 增加，尤其是 T4 下的 K 和 Mn 与防御能力有关。结果表明，对于容器栽培的 D. erecta 幼苗，在过量 Cu 条件下，存在一个 Cu 阈值来平衡根系缠绕控制、防御能力和养分吸收功能。
