Study On Honey-Derived Traits Of Six Robinia Pseudoacacia Germplasms

Robinia pseudoacacia is one of the most widely planted tree species in deciduous broad-leaved plantation in China.It is fast-growing,has excellent material quality and rich nutrients in leaves and flowers.It has many uses and research values in wood,forage and honey sources.Robinia pseudoacacia is one of the main nectar plants in China.But there are many varieties of Robinia pseudoacacia and few single varieties of Robinia honey on the market.Robinia pseudoacacia honey is in great demand in the honey market at home and abroad,but there are few studies on the cultivation of its nectariferous forest and nutrients.In this study,we observed,tested,determined and analyzed the nutrient components and active substances of Robinia pseudoacacia flower,the anatomy of nectary development and the investigation of Robinia pseudoacacia flower display.Two varieties of Robinia pseudoacacia nectar source forest,‘Duocai Qingshan’and‘Miyuan No.1’,were selected from the clones and new germplasms of Robinia pseudoacacia.(1)The content of nutritive active material in flowers of different germplasms of Robinia pseudoacacia was tested to provide scientific basis for the selection and breeding of honeywort linliang.According to relevant national standards,the content of total sugar,reducing sugar,L(+)-ascorbic acid(VC),protein,anthocyanin,total flavonoids and total saponins were respectively detected.The results of variance analysis showed that the contents of nutrients and active substances in all 6 germplasms of Robinia pseudoacacia were significantly different(P<0.01).The contents of total sugar and reducing sugar of the multiple Robinia neo-mexicana var.luxurians,‘Duocai Qingshan’and‘Miyuan No.1’were higher,which were 31.41g/100 g ~ 34.52g/100 g and 24.74 g/100 g ~ 28.07 g/100 g.The Robinia viscosa of VC and protein were highest at 233.4mg/100 g and 26.65 g/100 g,respectively.The contents of anthocyanins of Robinia neo-mexicana var.luxurians Dieck,‘Duocai Qingshan’and ‘Xingci 22’ was higher,which were 0.14% ~ 0.25%.The varieties with higher total flavonoids content were ‘Luci 58’,‘Duocai Qingshan’,Robinia neo-mexicana var.luxurians and ‘ Miyuan No.1 ’,which were within the range of 294.88mg/100 g ~442.92mg/100 g.The varieties with higher content of total saponins were Robinia neo-mexicana var.luxurians,‘Luci 58’,‘Duocai Qingshan’,‘Miyuan No.1’and Robinia viscosa,within the range of 0.31 g /100 g ~ 0.37 g /100 g.(2)Paraffin sections were prepared at different development stages of Robinia pseudoacacia flowers,including early bud stage,exposure stage,beginning stage,anthesisperiod and withering stage.The results showed that the nectary of Robinia pseudoacacia flowers was located on the receptacle between the ovary and the stamens,belonging to the receptacle nectary.The nectary contained starch grains,which belonged to the starch type.From the early bud stage and exposure stage to the beginning stage,the nectary cells arranged from loose to close,the cytoplasm gradually became thin,vacuoles in the cells gradually increased,and starch grains gradually formed and accumulated.From the anthesis period to the withering stage,the arrangement of nectary cells became loose to atrophy and deformation,the cytoplasm vacuolated completely,and starch grains began to decrease and disappear.(3)In order to compare the flower display of six species of Robinia pseudoacacia,three Robinia trees of the same age with the same tree potential of each variety were selected and observed,measured and counted at the flowering stage.The contents include florescence,total inflorescence volume,inflorescence on annual branches,inflorescence per inflorescence,total floret number,length of inflorescence,floret width,weight of inflorescence and water content of flowers.‘Miyuan No.1’is outstanding in flower quantity,that had the highest inflorescence on annual branches,inflorescence per inflorescence,total inflorescence volume,and total floret number.The longest flowering period of Robinia viscosa was 38 days,followed by Robinia neo-mexicana var.luxurians for 32 days.Their flowers are longer and wider than the other four.The maximum moisture content was 88.85% and the minimum was79.67%.They were Robinia viscosa and ‘Miyuan No.1’,respectively.