Evaluation Main Biological Characteristics Of Jianyang Tangelo Introduction In Guangxi

Jianyang Tangelo is one of the citrus varieties introduced in Guangxi in recent years.To clear and evaluate the reasons for the introduction fitness,resistance,and seedless or low nucleus characteristics of Jianyang Tangelo in Guangxi,provide reference for introduction,cultivation and utilization of germplasm resources.The paper studied the biological characteristics of Jianyang Tangelo,its flowering habits,pollination,fertilization,and embryonic development,the structure of leaves and the correlation between biochemical substances and ulcer resistance.The main results are as follows:(1)Jianyang Tangelo extracted spring shoots in early March in Guangxi,buds appear in mid-March,and flowered in late March.Flowering lasts until mid-April,the first physiological drop in late April,and fruit ripening in mid-December.The flower of Jianyang Tangelo was a complete flower,composed of calyx,corolla,stamen and pistil.The structure of flower organs was complete.The pollen germination rate of in vitro culture was 8.68%.The average fruit weight was 355.04 g,the fruit shape index was 0.91,the soluble solids content was 10.55%,the soluble sugar content was 7.40%,the titratable acid content was 0.22 g/100 mL,the Vitamin C content was 37.17 mg/100 g,and the average number of full seeds are 2.1 tablets/fruit.(2)The fluorescence microscopy observation of pollen tubes showed that after pollination for 4h,the pollen began to germinate normally on the stigma.After pollination for 48h,the pollen tube extended into the ovary,pollen tube was observed to enter the ovule after 72h of pollination,and the fertilization was observed;After pollination for 4h,pollen germinated normally on the stigma.After pollination for 24h,the pollen elongated into the ovary.After 48h of pollination,the pollen tube was observed to enter the ovule and fertilization was completed.(3)Early embryonic section observations showed that embryos developed normally after one week of pollination and two weeks after pollination,cavities appeared inside the ovules.Three weeks after pollination,embryo development could not be changed from heart-shaped embryos to torpedo embryos.The phenomenon of early abortion occurred;after one week of cross-pollination,the embryo developed normally and was in the early spherical embryo form.Two weeks after pollination,the embryo developed to a globular embryo morphology.After three weeks of cross-pollination,some embryos showed cavities inside,and there were also early failures.(4)The sensitivity rate of Jianyang Tangelo field stubble disease was 0,and that of control(Orah)was 55.80%.After in vitro acupuncture inoculation of ulcer bacteria,the incidence of Jianyang Tangelo leaf was 3.56%,the average lesion size was 0.056cm2,the incidence of Orah leaf was 93.28%,the average lesion size was 0.156cm2,Jianyang Tangelo is more resistant to canker disease.(5)The observation of the Jianyang Tangelo and the Orah leaves showed that the stomatal density of the leaves of Jianyang Tangelo was 756.00/mm2,which was significantly less than that of Orah.The thickness of the leaves was 247.07 μm,the thickness of the palisade tissue was 60.09 μm,and sponge tissue was found.The thickness was 157.84 μm,which was significantly greater than that of Orah,indicating that the anti-ulcer properties of Jianyang Tangelo are related to the lower stomatal density and thicker leaf structure.(6)Before the inoculation of the ulcer bacteria,the contents of MDA in the leaves of Jianyang Tangelo and Orah were 4.94 nmol/g and 6.39 nmol/g.The Orah was significantly higher than that of Jianyang Tangelo.After inoculation,the contents of MDA in Jianyang Tangelo and Orah both showed an upward trend.After 7 days,they were 14.58 nmol/g and 20.38 nmol/g,respectively.The Orah was higher and the difference was significant.MDA content was negatively correlated with ulcer resistance.(7)The activities of CAT,POD and SOD in leaves of Jianyang Tangelo and Orah before inoculation were 24.67 U/g and 56.33 U/g,3691.67 U/g and 5489.33 U/g,113.03 U/g and 138.77 U/g,the activity of three enzymes in the leaves of Orah was significantly higher than that of Jianyang Tangelo.After the leaves were inoculated with the canker,the activities of CAT and POD in the leaves of Jianyang Tangelo and Orah were all increased.The maximum values of CAT activity and POD activity in Orah were higher than those in Jianyang Tangelo.The activity of SOD was increased in the leaves inoculated with Jianyang Tangelo,but the activity of SOD in the leaves of Orah first decreased and then increased.However,the difference between the maximum value of SOD activity in leaves of Jianyang Tangelo and the maximum value of SOD in leaves of Orah was not significant.Based on the results of this study,Jianyang Tangelo was introduced in Guangxi,where it could grow normally and bear flowering results.It was a mid-maturing variety,and its fruit quality was medium-upper,less-nucleated or non-nuclear,and its anti-ulcer disease was strong.However,the natural fruit setting rate is low,and it is easy to produce dried fruit.High yield,stable yield and other traits need further observation and evaluation.