Studies On Cyanide-resistant Respiration During Different Senescence Process Of Several Cut Flowers

Fresh Carnation and Chrysanthemum cut flowers, detached and attached Narcissus flowers, storage Peony cut flowers were used as materials in this study. The changes of Cyanide-resistant respiration were discussed during different senescence process in these cut flowers. The relationship between cyanide-resistant respiration and senescence was also discussed from the viewpoint of active oxygen. The aim of this paper was to know further about the senescence physiology of cut flowers, and it could provide theoretic basis for the development of new preservations. The results showed that:â‘  Cyanide-resistant respiration could participate the senescence process in cut flowers, but both V_alt / V_t ratio and changing trends were different, showed that it may have different effect during senescence process.â‘¡ Ethylene was the main factor that initiated senescence in Carnation cut flowers. The membrane-lipid permeability caused by imbalance of active oxygen metabolism led to senescence in cut chrysanthemum cut flowers. Cyanide-resistant respiration rate could eliminate active oxygen in both ethylene climacteric and nonclimacteric cut flowers, but it was more dynamic in Chrysanthemum cut flowers (ethylene nonclimacteric type). In Chrysanthemum cut flowers, the enhancement of superoxide radical (O₂^·|- ) production had inducing effects on cyanide-resistant respiration, and this was further proved by inhibiting the activity of superoxide dismutase (SOD), adding exogenous O₂^·|- or active oxygen scavenger. The induction was not appeared in Carnation cut flowers. Cyanide-resistant respiration still had self-adjustment ability after senescence in Chrysanthemum cut flowers, but in Carnation cut flowers it varied slowly and kept invariant.â‘¢ Compared with attached flowers, the Narcissus cut flowers had longevity one-day shorter.The imbalance of active oxygen metabolism in cut flowers was the main reason leading to accelerated senescence. The cyanide-resistant respiration rate in Narcissus cut flowers was induced by the enhancement of O₂^·|- and got its maximum when the petals showed typical characteristics of senescence. No induction phenomena appeared in attached flowers. Different with Carnation and Chrysanthemum cut flowers, cyanide-resistant respiration rate in Narcissus cut flowers sharply decreased after vase, but in attached flowers it maintained in a higher level at the earlier stage of blooming, and this may be one reason that attached flowers had longer life. Because cyanide-resistant respiration was helpful to the elimination of active oxygen, it could delay membrane-lipid permeability.â‘£ There were some differences in vase life and blooming rate during storage among different Peony cut flower cultivars. The membrane-lipid peroxidation was not the only reason to the membrane damage during storage time. Cyanide-resistant respiration could participate in the storage period by lowering the level of active oxygen species and abating the degree of membrane -lipid peroxidation. The cultivars with longer vase life had higher level of cyanide-resistant respiration, and the enhancement of cyanide-resistant respiration during storage time was helpful for maintaining the quality after storage. By comparison, the cultivars which cyanide-resistant respiration rate increased steadily during storage time had better storage stability.