Effects Of Growth Regulators On Morphological And Physiological Indicators Of Desk Chrysanthemum

At present,the breeding and cultivation process of Desk Chrysanthemum is difficult,and the professional and technical requirements are high,in the process of production and cultivation of Desk Chrysanthemum,there is no clear and unified standard for variety selection and growth regulator types and dosage,problems affecting its commodity value often arise in cultivation.With the growth regulators commonly used in the production of Desk Chrysanthemum,problems have been reported successively,which makes the production and cultivation of Desk Chrysanthemum in a dilemma.Therefore,it is very important to study the selection of growth regulators and their intrinsic physiological regulation mechanism of Chrysanthemum morifolium.Through investigating more than 500varieties in the Chrysanthemum Planting Resources Reserve Base of Beihai Park in Beijing,the flower color,plant height,inflorescence diameter,flowering period and growth potential of the selected chrysanthemum varieties were recorded under natural flowering cultivation conditions,and three representative chrysanthemum varieties（Shuai Qi,Huan Shuiheixuanfeng,Gu Shuilvping）were finally selected to adapt to Desk Chrysanthemum cultivation.The spraying experiment of growth regulator was carried out.Pot experiments and laboratory tests were used to study the effects of growth regulator on morphological indexes（plant height,stem diameter,leaf length,leaf width,petiole length,stem node length,inflorescence diameter）,comprehensive scores,the effects of osmotic regulators（SP、MDA）and protective enzymes（SOD、POD）were studied.In this experiment,more than 500 varieties of Chrysanthemum in Beihai Park of Beijing were investigated.Three representative chrysanthemum cultivars（Shuai Qi,Huan Shuiheixuanfeng and Gu Shuilvping）adapted to desk chrysanthemum cultivation were screened out and sprayed with growth regulators.The effects of growth regulators on morphological indexes,comprehensive scores,osmotic regulators and protective enzymes activities of desk chrysanthemum were studied by pot experiments and laboratory tests.Laboratory physiological index test results showed that:osmotic regulators,spraying growth regulators after the MDA content of desk chrysanthemum were first decreased,then increased and then decreased,overall reduced the content of MDA in desk chrysanthemum,improved the stress resistance of the plant,strengthened the physiological function of desk chrysanthemum leaves,and then improved the quality and ornamental of desk chrysanthemum.SP content showed a gradual upward trend,and the increasing process of SP content was different among different desk chrysanthemum varieties.In terms of protective enzymes activity,SOD increased first and then decreased slowly after spraying growth regulators,and high concentration of growth regulators could inhibit SOD activity.However,POD activity showed an overall upward trend,and the DPC treatment reached its peak earlier than B₉treatment,and then decreased slightly.The higher the concentration of growth regulator,the higher the POD activity.Pot experiment results showed that the higher the concentration of growth regulator was,the more the height of Chrysanthemum morifolium decreased.Among them,I2 concentration （B₉2000 mg/L）and II3 concentration（DPC 4000 mg/L）had the best dwarfing effect.The bigger the concentration of B₉was,the smaller the stem diameter was.The bigger the concentration of DPC was,the bigger the stem diameter was.The leaf length,leaf width and petiole length of Chrysanthemum morifolium were all reduced under the treatment of two growth regulators,and the higher the application concentration,the lower was about significant.The leaves of Chrysanthemum morifolium treated by DPC were dark green and lustrous,and its ornamental value was higher than that of B₉.Growth regulator had no significant effect on the number of nodes of plant stem.After the application of growth regulators,the delays of budding and transpiration and flowering stages were observed,and the higher the concentration of medicament,the more obvious the delays were.Meanwhile,the length of stem nodes and inflorescence diameter also showed a decreasing trend with the increase of concentration.The results showed that DPC could achieve the same Dwarfing Effect as B₉in the cultivation of desk chrysanthemum,and the quality of desk chrysanthemum was higher than B₉.The optimum application concentration of Shuaiqi was II2（DPC 3000 mg/L）,the optimum application concentration of Kushui Black Cyclone was II2（DPC 3000 mg/L）,and the optimum application concentration of Dushui Green Azolla was II2（DPC 3000 mg/L）in the cultivation of desk chrysanthemum.The ornamental value of treated chrysanthemum plants was higher than that of DPC 4000 mg/L.The treated chrysanthemum plants have compact overall plant shape,dark green leaves,luster,good overall effect,neat and beautiful,and stronger ornamental value.