The Biological Characteristics Of The Main Cultivated Vitis Vinifera In Jinan And Their Flowering And Pollination Ecology

The flowering period,the floral comprehensive characteristics,the types of visiting insects and the visiting behavior of the main cultivated varieties of Vitis vinifera("Guifeimeigui","Kyoho","Fujiminori" and "Jumeigui")were studied in Jinan.The microscopic morphological characteristics of pollen,stigma and nectary of grape were observed by scanning electron microscope(SEM).The pollen viability,pollen nutritional composition and stigma receptivity of the grape were tested in the laboratory.The main results are as follows:The time of entering the initial flowering stage of grape populations were affected significantly by climate,especially temperature,but the length of single flowering period was not affected.In 2014,the flowering period of four grape varieties began in early May,lasted two weeks.The temperature of 2015 rose slowly,flowering period began in mid-May,finished in the end of May.In 2016,temperature varied greatly,the flowering periods of the four varieties were different.Guifeimeigui blossomed in early May,and the other three varieties entered the initial flowering stage in mid-May.Flowering rate increased with the temperature rise,the decrease in temperature led to a decrease of the flowering rate in the next day.The constant temperature and humidity of greenhouse can make the flowering period of grape began 2-3 weeks earlier,but it has little effect on the length of flowering period.The complete flower of the grape consists of pedicel,receptacle,calyx,nectary,stamens,pistil and other parts.The corolla is small,green,like a cap,separate after flowering.The flower diameter is about 9~11mm,the height is about 5~8mm,the distance between anther and stigma is about 3~7mm.Pollen-Ovule ratio(P/O)is more than 1000,indicating that the breeding system type is facultative outcrossing,the crossing index(OCI)is 3,which indicates that the breeding systems of these grape varieties are self-compatible,and need pollinators sometimes.Grape pollen is nearly round,with three or four hole groove,slender and connected at the top,a germination hole at the middle of the hole groove,reticular or hole-like decoration on the pollen surface.The pollen of the grape can germinate well in the sucrose solution with appropriate temperature.The pollen viability reaches more than 20% one day before the opening,and reaches the maximum value of about 80% 6 hours after opening.After 72 hours of flowering,the pollen vitality of grape remained about 10%,and there was no significant difference among varieties.The cold storage conditions was favor to maintain pollen viability,the pollen vitality of grape was still more than 30% after stored at-20℃ for 3 weeks.The stigma of the grapes becomes uneven a day before flowering,its epidermal cell proliferate to mastoid cells for acceptance of pollen,the stigma receptivity also reaches the strongest,then loss in three days after flowering.The nectarines of grapes become open and larger after the flowering,its color turn green to yellow gradually.Sugar,protein,amino acid and vitamin are the main components of grape pollen.The content of soluble sugar in grape pollen is about 1~3%,amino acid is 50~100mg/kg,protein is less than 5%,and the content of each component is lower than that of nectar source(soluble sugar: 25-48%,amino acid: 130 mg / kg,protein: 20%).Main pollinators category of different grape varieties is similar basically,mostly belongs to Hymenoptera and Diptera of Insecta,in which Apis melliferaligustica Spinola,Episyrphus balteata De Geer and Camponotus japionicus Mary are the main pollinators.Visiting insects generally have two visiting peaks in one day.The peak of visiting in the morning is from 10:00 to 11:00,mainly by Apis melliferaligustica Spinola and Episyrphus balteata De Geer.The average visiting frequency is about 30~50 times in a quarter of an hour during the peak period,while the nectariferous plant(Vitex negundo L)at the same flowering time can be more than 100 times in a quarter of an hour.Bagging with emasculation and stick with PVA confirmed that most of the cultivated grapes had been fertilized(cleistogamy)before the opening of flowers,which was the result of long-term natural selection and artificial breeding.Pollination insects not only have an adjunctive effect on grape pollination,they may also help to improve the ecological stability of vineyards.In summary,the study found that the time of entering the initial flowering stage of grape populations were affected significantly by climate while the length of single flowering period was not affected.The parameters of the flower and the components of the pollen were also studied.The study could deep the understanding on the pollination ecology and has implications for the cultivation,breeding and protection of grape.