单瓣与重瓣紫斑牡丹象牙白花器官衰老生理生化特性研究OA

To explore the physiological mechanism underlying the different senescence processes between single-petal and double-petal flowers of Paeonia rockii'Xiangyabai'and to provide a theoretical basis for flowering regulation and anti-senescence breeding of Paeonia rockii,this study compared the physiological and biochemical characteristics associated with senescence using single-petal floral organs(petals,pistils,sepals)and double-petal floral organs(normal petals,petalized petals,pistils,sepals)at 4 flowering stages(color-showing,initial-bloom,full-bloom,and initial-decline).Soluble protein content,malondialdehyde(MDA)con-tent,and the activities of superoxide dismutase(SOD)and peroxidase(POD)were measured.Morphological observation confirmed that the petalized petals of double-petal flowers senesced earlier than the petals of single-petal flowers.Biochemical results showed that MDA content in all organs of double-petal flowers was significantly higher than that in single-petal flowers at all stages,indicating more severe membrane lipid peroxidation damage.All organs of single-petal flowers,as well as the petalized petals and pistils of dou-ble-petal flowers,exhibited"induced enzyme characteristics",with enzyme activity increasing during the later stage of development.In contrast,the normal petals and sepals of double-petal flowers exhibited a"loss of protective enzyme characteristics",with enzyme activity collapsing after the full flowering stage.The soluble protein content in sepals and pistils remained elevated during the initial-decline stage,suggesting their senescence was delayed compared to that in petals.The accelerated senescence in double-petaled'Xiangyabai'flowers was primarily attributed to the excessive accumulation of MDA and the premature collapse of the antioxidant de-fense system,especially in the normal petals and sepals.