为解决沙冬青（Ammopiptanthus mongolicus）主根长、毛细根少,育苗生根困难、移栽成活率低的林业技术难题,该研究对不同发育程度沙冬青幼苗进行不同强度断根与不同浓度激素处理（IBA）添加,促根培养后测定并分析不同组合处理对沙冬青幼苗根系形态、根系质量及幼苗生长的影响,以探究沙冬青促根成活关键措施,为沙冬青育苗及造林技术提供基础依据。结果表明：（1） 断根可促进沙冬青多主根的发生,以及侧根、根总量、幼苗地上地下部分生物量、根冠比、根系活力和根系阳离子交换量（CEC）的增加。其中,幼苗根长达1.5~2.0 cm时断根尖0.5 cm（F2）处理显著促进侧根数、根尖数、分支数、苗木质量指数和根系活力的增加,且根系活力达到断根处理的峰值（较对照显著提高137.70%）;根系CEC在根长达4.5~6.0 cm时断根长1/2（T3）处理时最佳。（2） 断根后激素的促根及幼苗生长作用进一步提高。其中,根长1.5~2.0 cm时断根尖0.5 cm+0.075 mg·L^-1 IBA/0.125 mg·L^-1 IBA（即P3、P4）处理后根系形态指标（除平均根长外）、根系CEC显著大幅增加;P4处理后幼苗鲜重、根干重、根冠比、苗木质量指数和根系活力最高。P3处理下根中可溶性糖、NSC含量较对照显著增加26.04%和29.07%,根可溶性蛋白含量在P4处理下达到峰值（13.27 mg·g^-1）。适当断根与IBA添加可通过改变根系形态和提高根系活力一定程度上促进沙冬青根系吸收和养分存储,进而提高根系质量和幼苗生长潜力。

To solve the technical problems associated with forestry of Ammopiptanthus mongolicus, i.e., the long main root, few capillaries, difficult rooting, and low transplantation survival rate, we conducted root cuttings at different intensities and added different concentrations of IBA to A. mongolicus seedlings with different degrees of growth development. The effects of different treatment combinations on root morphology, root quality, and seedling growth were then measured and analyzed after root culture. This investigation was aimed at identifying the key measures for promoting the root survival of A. mongolicus seedlings and thereby providing a knowledge base for cultivating A. mongolicus seedlings and developing afforestation techniques. The results were as follows. (1) Root cutting promoted the occurrence of multimain roots in A. mongolicus, as well as an increase in the lateral roots, total roots, aboveground and underground biomass, root-shoot ratio, root activity, and root cation exchange capacity (CEC). Among the treatments, the 0.5-cm root tip treatment (F2) significantly promoted an increase in lateral root number, root tip number, branch number, seedling quality index, and root activity when the root length reached 1.5-2.0 cm. Root activity reached a peak value with the root cutting treatment (137.70% higher than the value in the control). Root CEC was maximal when root length reached 4.5-6.0 cm. (2) The effect of hormones on promoting root and seedling growth was further improved after root cutting. The root morphological index (except the average root length) and root CEC were significantly increased after 1.5-2.0 cm long roots were treated with 0.5 cm cutting + 0.075 mg·L ^-1 IBA/0.125 mg·L^-1 IBA (P3 and P4 treatments, respectively). Seedling fresh weight, root dry-weight, root-shoot ratio, seedling quality index, and root activity were highest under the P4 treatment. Compared with the control, the content of soluble sugar and NSC in roots under P3 treatment was significantly increased by 26.04% and 29.07%, respectively. Additionally, the content of soluble protein in roots reached its peak under the P4 treatment (13.27 mg·g^-1). Proper root cutting and the addition of IBA can promote root absorption and nutrient storage of A. mongolicus by altering root morphology and improving root activity, which in turn improves root quality and the growth potential of seedlings.