Abstract: This study aimed to investigate the effects of zinc oxide nanoparticles（ZnO NPs）on adventitious root formation in apple rootstock M26，so as to provide a novel strategy for efficient tissue culture‐based rapid propagation of apple seedlings.Using tissue‐cultured seedlings of apple rootstock M26 as the experimental material，different nanomaterial treatment groups（ZnO NPs，TiO_₂ NPs，etc.）and a conventional IBA rooting medium as control group（CK）were established. Through phenotypic observation，physiological and biochemical index measurements，and the related gene expression analysis，the effects of ZnO NPs on adventitious root formation were systematically studied.The results showed that ZnO NPs treatment significantly improved the rooting rate，root length，and root surface area of M26，while also promoting biomass accumulation in tissue‐cultured seedlings.Additionally，ZnO NPs enhanced chlorophyll synthesis and the uptake of Zn and K.For instance，Zn content increased by approximately 12.4‐fold in shoots and 6.5‐fold in roots，while K content increased by 16.4% and 9.0%，respectively. Furthermore，auxin pathway genes（MdAUX1） were significantly upregulated at 6 d，while transcription factor genes（MdLBD16，MdWOX5）were upregulated to 1.3‐ and 1.8‐fold of the CK level，respectively，whereas the negative regulator MdTCP17 was significantly downregulated during 2—6 d post treatment.ZnO NPs significantly promoted adventitious root formation in apple rootstock M26 by improving nutrient uptake，enhancing photosynthesis，and modulating the expression of key genes.

Key words: Apple, Rootstock, ZnO NPs, Adventitious roots, Auxin

摘要： 探究纳米氧化锌颗粒（ZnO NPs）对苹果砧木M26不定根形成的促进作用，为苹果苗木高效组培快繁提供新策略。以苹果砧木M26组培苗为材料，设置不同纳米材料处理组（ZnO NPs、TiO₂ NPs、WO₃NPs、Fe₃O₄ NPs和Fe₂O₃ NPs等）和常规IBA生根培养基对照组（CK），通过表型观察、生理生化指标检测及相关基因表达分析，系统研究ZnO NPs对其不定根形成的影响。结果表明，ZnO NPs处理显著提高了M26的生根率、根长和根表面积，并促进了组培苗生物量的积累。此外，ZnO NPs增强了叶绿素合成和Zn、K等元素的吸收，Zn含量在地上部和地下部分别提高12.4倍和6.5倍，K含量也分别提高16.4%和9.0%，同时生长素途径基因（如MdAUX1）在6 d内显著上调，转录因子基因（如MdLBD16、MdWOX5）分别上调至CK的1.3倍和1.8倍，负调控因子MdTCP17的表达在处理后2~6 d则显著下调。ZnO NPs通过促进营养吸收、增强光合作用及调控关键基因表达，显著促进了苹果砧木M26不定根的形成。

关键词: 苹果, 砧木, 纳米氧化锌, 不定根, 生长素