为探明纳米镁和离子镁对寒地香稻品种牡育稻49生长、产量和品质的影响，开展了不同形态镁肥施用试验。结果表明，相较于常规施肥处理，添加纳米镁处理的牡育稻49在抽穗至成熟阶段叶片SPAD值、干物质积累量以及产量最高，其次是添加离子镁的处理。镁肥的施用显著增强了籽粒灌浆全过程中ADPG焦磷酸化酶和可溶性淀粉合成酶的活性，并显著提升了淀粉分支酶在籽粒灌浆前期的酶活性，但显著降低谷氨酰胺合成酶在籽粒灌浆前期的酶活性。此外，加施镁肥还显著提高了糙米率、整精米率、胶稠度和食味评分，同时降低了垩白粒率、垩白度和直链淀粉含量，且在糙米率、整精米率和食味评分方面，纳米镁的施用效果要优于离子镁。在籽粒淀粉的理化特性上，镁肥的施用显著提高了淀粉的最高黏度和崩解值，而有所降低热浆黏度、冷胶黏度和消减值，这进一步证明了镁肥对于提升稻米蒸煮食味品质的有效性。综上所述，在牡育稻49栽培过程中适量施用镁肥，不仅能够提高产量，还能提升稻米品质，且纳米镁肥较离子镁肥施用效果更好。

To investigate the effects of nano-magnesium and ionic-magnesium on the growth, yield, and quality of aromatic rice variety Muyudao 49 in cold region, an experiment of applying different forms of magnesium fertilizer was conducted. The results showed that compared to the conventional fertilization treatment, the treatment with the addition of nano-magnesium had the highest SPAD value of leaves, dry matter accumulation, and yield from the heading stage to the maturity stage of Muyudao 49, followed by the treatment with the addition of ionic magnesium. The application of magnesium fertilizer significantly enhanced the enzyme activity of ADPG pyrophosphate synthase and soluble starch synthase throughout the grain filling process, significantly increased the enzyme activity of starch branching enzymes in the early stage of grain filling, and significantly reduced the enzyme activity of glutamine synthase in the early stage of grain filling. Additionally, the application of magnesium fertilizer significantly improved the brown rice rate, whole grain rate, gel consistency, and taste score, while reducing the chalkiness rate, chalkiness degree, and amylose content. Moreover, the treatment with the addition of nano-magnesium was superior to that of ionic magnesium in terms of the improvement in brown rice rate, whole polished rice rate, and taste score. In terms of the physical and chemical properties of grain starch, the application of magnesium fertilizer significantly increased the highest viscosity and breakdown value of starch, while decreased the hot paste viscosity, cool gel viscosity, and setback value, further demonstrating the effectiveness of magnesium fertilizer in improving the cooking and taste quality of rice. In summary, applying an appropriate amount of magnesium fertilizer during the cultivation of Muyudao 49 can not only increase yield but also improve the quality of rice, with nano-magnesium fertilizer being more effective than ionic magnesium fertilizer.