| Carnation(Dianthus caryophyllus L.)has high ornamental value and commercial value.According to the use,it can be divided into potted and cut flowers.Carnation is a typical ethylene-sensitive flower,and ethylene promotes the senescence of its petals.The study found that there were significant differences in the vase life and ethylene sensitivity of different carnation cut flower varieties.In recent years,potted carnations have become more and more popular in the international market,but so far there are few reports on the senescence mechanism of potted carnations.Therefore,in this study,17 commercially available potted carnation varieties in the mainstream of the market were used as materials,and the vase life span under standard post-harvest environmental conditions was considered as the inherent flower life span of potted carnations determined by genes.Flower life span,ethylene production and ethylene sensitivity of 17 potted carnation varieties were investigated to analyze and compare the varietal variability of ethylene biosynthesis-related genes,water relations,volatile substances and anthocyanin glycosides during flower senescence in different varieties to provide some scientific basis for selecting potted carnation varieties with long flowering period and high ornamental quality.The findings are as follows:(1)The flowering period and vase life of the 17 potted balsam varieties varied widely.‘Purple Wings’ had the longest single flowering period of 24±3.7d,while ‘Grane Beach’and ‘Grace Bay’ had the shortest single flowering periods of 10±2.4d and 10±3.0d,respectively.‘Cherry’ and ‘Salmon’ had the longest vase life of 14±2.4d and 14±2.7d,respectively,while ‘Grane Beach’ and ‘Grace Bay’ had the shortest single flowering life of 10±2.4d and 10±3.0d,respectively.‘Grane Beach’ and ‘Grace Bay’ had the shortest vase life of 6.2±0.8d and 6.9±0.7d,respectively.(2)The sensitivity to ethylene varies considerably among potted carnation species.among the 17 potted carnation varieties,‘Cherry’ and ‘Grace Bay’ were highly sensitive to ethylene,and the expression of ethylene biosynthesis genes Dc ACS1 and Dc ACO1 increased the most.‘Pink and Purple’,‘Bondi Beach’ and ‘Grane Beach’ were the least sensitive to ethylene,and the expression of Dc ACS1 and Dc ACO1 increased the least;(3)Ethylene damage and water stress are the main factors affecting the flower longevity of potted carnation.The water absorption of long vase life varieties increased first and then decreased,while that of short vase life varieties continued to decrease.The change range of long vase life varieties was gentler than that of short vase life varieties,and the change trend of water absorption and water loss of the same variety was consistent.Compared with low ethylene sensitive varieties,the days of maintaining positive water balance and fresh weight of flowering branches of high ethylene sensitive varieties decreased greatly.Among the 17 varieties,The ethylene release of ‘Oscar’,‘Red Star’ and ‘Cherry’ belonged to terminal rising type,and the rest belonged to ethylene climacteric type.All varieties showed ethylene jump peak at 8h or 12 h after ethylene treatment.Ethylene production of varieties with long vase life is 2.5-4.5 times of varieties with short vase life;(4)A total of 63 volatile compounds were detected in the petals of potted carnations.The types and contents of alkanes were the highest,followed by alcohols and phenols.In addition to alkanes,the relative content of phenolic compounds in ‘Blinky Beach’ and‘Grace Bay’ was the highest,and the proportion of alcohols in the rest varieties was the largest.Ethylene promoted the volatilization of 2,4-di-tert-butylphenol,1-(chloromethyl)-2,4-xylene,eugenol,2,5-dimethylbenzaldehyde and inhibited the volatilization of behenol;(5)A total of 11 anthocyanins were detected in the petals of potted carnations,including 5 pelargonidin anthocyanins and 6 cyanidin anthocyanins.The main components of ‘Blinky Beach’ and ‘Grace Bay’ were cyanidin 3,5-O-rhamnosideglucoside(Cy3Rha5G),and the main components of other varieties were cyanidin 3-Omalonyl-glucoside(Cy3Ma G).Ethylene treatment significantly reduced the relative content of cyanidin-3-O-glucoside(Cy3G)in petals of ‘Cherry’ and the relative content of cyanidin-3,5-O-rhamnoside-glucoside(Cy3Rha5G)in petals of ‘Grace Bay’. |
