Objective  This paper aims to explore the effects of uniconazole on the physiological characteristics and microstructure of potted Paeonia lactiflora, in order to provide a certain reference for the commercial production of potted P. lactiflora.

  Method  The cultivar ‘Dafugui’ was used as the experimental material, the leaves were sprayed with uniconazole (40 mg/L) as the treatment, and the leaves were sprayed with clean water (0 mg/L) as the control. Physiological characteristics and microstructure of the leaves and roots were measured and observed at four different growth and development stages (leaf-expansion stage, flower-bud stage, pigmented stage, full-flowering stage) of potted P. lactiflora.

  Result  Compared with the control, uniconazole treatment can significantly reduce the production and accumulation of thiobarbituric acid reactive substances (TBARS) in the leaves and roots of potted P. lactiflora, increase cell membrane permeability, maintain cell membrane stability, and thereby increase the adaptability of potted P. lactiflora to the environment. The total chlorophyll and carotenoid contents of potted P. lactiflora initially increased but then decreased and were highest at the pigmented stage. After the treatment of uniconazole, the leaves of potted P. lactiflora were thicker with the sponge and palisade tissue cells arranging tightly and orderly. Compared with the control, the proportion of the root stele was larger, the proportion of the cortical cell became smaller.

  Conclusion  Studies have shown that foliar spraying uniconazole can effectively improve the environmental adaptability of potted P. lactiflora, increase the contents of photosynthetic pigment, and change the internal tissue structure of leaves and roots. Foliar spraying with uniconazole may be an effective measure for potted plants production.