The Study On Postharvest Hormonal Senescence Characteristics And Evaluation Of Cold Storage Of Some Cut Chrysanthemum

Chrysanthemum(Chrysanthemum morifolium Ramat.)is one of the top ten traditional flowers in China and one of the four largest cut flowers in the world.With the development of the economy and the improvement of people’s living standards,people’s pursuit of quality of life and spiritual civilization has been continuously improved,so the demand for cut flowers has been increased.In 2016,China,chrysanthemum planting area was 7,228.74 hectares,follows that of rose(15,729.85 hectares),volume of sales is 2.65 billion stems,and sales value is 1.52 billion yuan,ranking third place in the cut flowers.The chrysanthemum industry has become an important part of the crop industry(Takino et al.,2017).However,the water loss,wilting,and yellowing of the leaves post harvest greatly reduced the vase life and ornamental quality of the chrysanthemum,resulted in serious economic losses of cut chrysanthemum.Therefore,it is necessary to carry out investigation on post-harvest senescence type and post-harvest preservation technology of cut chrysanthemum.In this study,cut chrysanthemum cultivars with high ornamental value were used to testify their sensitivity to ethylene(ET),abscisic acid(ABA)and post-harvest cold storage.Through the comprehensive evaluation of leaves,flower morphology and vase life,the senescence of cut chrysanthemum in response to ethylene and ABA was analyzed.The type of tolerance to storage resistance was detected as well,which will lay a theoretical basis for the development of post-harvest preservation technology,thereby reducing post-harvest losses of cut chrysanthemum.The main results are as follows:1.The cut chrysanthemum was treated with Ethephon(200 mg/L,ET)and Abscisic acid(10-4 mol/L,ABA)for 24 h,respectively,and then placed in a vase with tap water.According to the days of yellowing of leaves and the vase life of leaves and flowers,the senescence sensitivity to ET and ABA were divided into three categories,namely ethylene-sensitive type including ’Zi Dante’,’Fen Dujuan’,’Nannong Hengchun’;Ethylene and Abscisic acid both sensitive type including ’Green Anna’,’Nannong Huanglongyu’,’Nannong Xiaocaomei’,’Nangnong Libai’,’Meng Hong’,’Fen Dante’,’Huanglue Tianzan’,’Qinhuai Fenxia’,’Nannong Zipingpang’,and non-Ethylene or Abscisic acid sensitive type including ’Zi Luoli’,’Fen Luoli’,and ’Ameide’.2.The response types of flower to ET and ABA are divided into 3 categories,ethylene sensitive type including ’Fen Dante’,’Nannong Hengchun’,’Ameide’,’Fen Dujuan’,’Nannong Zipingpang’,’MengHong’,’Nannong Libai’,’Nannong Huanglongyu’,’Qinhuai Fenxia’;’Nannong Xiaocaomei’,ethylene,abscisic acid sensitive:’Zi Dante’,’Huanglue Tianzan’,’Green Anna’,Ethylene,Abscisic acid are not sensitive:’Zi Luoli’,’Fen Luoli’.3.Above-mentioned ethylene and abscisic acid both sensitive varieties of ’Nannong Libai’,’Fen Dante’,’Meng Hong’ were subjected to ET(200 mg/L)and ABA(10-4 mol/L)ET+1-MCP(500 nl/L)and ABA+6-BA(2 mg/L)treatment.The control group was treated with clear water.It was found that the leaf vase life in the 1-MCP treatment group compared with the ET treatment group.They were extended by 2.83d,2.34d and 1.33d respectively.The fresh weight of ET treatment group was 91.8%,78.9%and 91.0%of ET+1-MCP treatment group,respectively.The chlorophyll content of ET treatment group was ET+1-MCP group 81.7%,71.2%,and 90.1%.About the ABA+6-BA treatment group and the ABA treatment group,the leaf vase life was extended by 1.84d,2.67d,and 1.33d,respectively,and the fresh weight of the ABA treatment group was ABA+6-BA 92.3%,85.5%,and 97.1%.And the chlorophyll content of the ABA treatment group were 89.6%,68.8%,and 84.0%,respectively,of the ABA+6-BA group.4.The cut chrysanthemum was packed into bundles according to the storage and transportation standards,then placed in a storage box,and stored in a cold storage room in the dark at 4℃ for 7 days,after that,the stored flowers were put in the vase with tap water.Based on the vase life of leaves and flowers,the type of response of the cut chrysanthemum to storage is divided into two categories,cold storage non-resistant type including ’Green Anna’,’Zi Luoli’,’Fen Luoli’,’Qinhuai Fenxia’,’Nannong Libai’,’Zi Dante’,’Ameide’,Huanglue Tianzan’.Varieties tolerant to cold storage including ’Meng Hong’,’Fen Dujuan’,’Nannong Xiaocaomei’,’Nannong Zipingpang’,’Nannong Hengchun’,’Nangnong Huanglongyu’,and ’Fen Dante’.