Genetic Diversity And Development And Utilization Of The Germplasm Resources Of The Champereia Manillana BL.

Objective:To study the genetic diversity,nutritional content,flavonoid content,antioxidant activity,and photosynthetic characteristics of the Champereia malillana BL.,which can provide a theoretical basis for the development and utilization of its excellent germplasm resources.Methods:（1）The orthogonal design and single factor design methods were used to optimize the ISSR-PCR reaction system of the d NTPs,Taq DNA polymerase,primers,template DNA,and Mg²⁺.The ISSR-PCR amplification system with good reproducibility was used to amplify all DNA molecules after screening all valid primers.After reading the bands,the relevant software was used to calculate the genetic diversity of the Champereia malillana.（2）On the basis of the single factor test,the response surface analysis method was used to optimize the extraction process of total flavonoids from the leaves of the Champereia malillana and study its antioxidant activity in vitro.The content of total flavonoids of the Champereia malillana in five regions of Guangxi was also determined.（3）According to the national standards for the determination of various nutritional components,the contents of main active substances,amino acids and mineral elements in the three parts of the stem,leaf and fruit of the Champereia malillana.（4）Using biennial cuttings as test materials,set 10%,30%,50%,and 100%light gradients to study the characteristics of growth and photosynthetic characteristics under different light intensities.Results:（1）Suitable ISSR-PCR reaction conditions are:in a 20μL reaction system,the concentration of d NTPs is 0.4 mmol/L,the amount of Taq DNA polymerase is 1.5 U,the concentration of primers is 0.8μmol/L,and the concentration of Mg²⁺is 2.0 mmol/L and the template DNA concentration is 45 ng.The amplification procedure is:pre-denaturation at 94℃for 5 min;denaturation at 94℃for 30 s,annealing at 52.9℃for 30 s,and extension at 72℃for 30 s.The above 3 steps are cycled 40 times,and finally 72℃extend for 10 min;the number of sites amplified by each primer of five natural populations of the Champereia malillana ranges from 3 to 7,and the molecular weight is within 100to 1500 bp,of which 45 polymorphic bands and the PPL is 100%,the I is 0.3581,the Ne is 1.6118,and the Nei’s gene diversity index（He）is 0.5348.Among the total genetic variation,16.51%occurred between populations,and 83.49%occurred within populations,the Nm=3.6790.The five populations are not divided according to geographical location.The four populations of Neidou,Longhushan,Nonggang,and Yuliang first converge into one group,and finally meet with Tianlin.The genetic distance of Tianlin population is the largest.The correlation between genetic distance and geographic distance between populations is not significant（r=0.5475,P=0.0680>0.05）.（2）The optimal extraction conditions for flavonoids are ultrasonic power 330 W,ultrasonic frequency 35 KHz,ethanol concentration 80%,material-liquid ratio 1:41.8 g/m L,extraction temperature at64.6℃,the extraction time is 50.7 min.Under these conditions,the total flavonoid yield is 2.83%.In addition,the optimal extraction of the Champereia malillana can clear·OH,O₂^-·and DPPH·.When the flavonoid concentration is 1mg/m L,the maximum clearances of·OH,O₂^-·and DPPH·are 13.27%,30.98%,38.68%,it has a good reduction ability,the total flavonoid content and antioxidant activity of the Champereia malillana in Yuliang is better than the Nonggang,Longhushan,Neidou and Tianlin.（3）From the perspective of total amino acids,young leaves>fruits>stems（P<0.05）,the total amino acids in the young leaves of the Champereia malillana are 5.83 g/100 g,which is about 3.89,2.69,3.33 of the Toona sinensis buds,Fennel,and Chrysanthemum coronarium.Except for Asp,Pro,Met,and Arg,the content of other amino acids was significantly higher than that of the other two parts,and the Glu content was the highest among the three parts,following are Asp and Met.The content of crude fiber,crude fat,and vitamin C in young leaves is significantly higher than that of common vegetables,and it has the characteristics of significantly high potassium and low sodium.The potassium content is about 4 times that of sodium.（4）A certain degree of shading is more conducive to the growth of the Champereia malillana.Under 50%light,the growth of plant height,ground diameter,and crown width are significantly higher than those of the 10%,30%and 100%（P<0.05）;Light intensity has a significant effect on photosynthetic characteristics of the Champereia malillana.50%light is beneficial to improve its stomatal conductance and transpiration rate.Conclusions:（1）There is a high level of genetic diversity in the Champereia malillana.Among the total genetic variation,16.51%occurred among populations and 83.49%occurred within populations.The population with the highest genetic diversity is the Tianlin population,which has a high degree of genetic variation.It is recommended that this population be used as a key protection unit.The gene flow between populations is strong and it is not easy to inherit differentiation.（2）The total flavonoid content of the leaves of the Champereia malillana is not high.The total flavonoid content and antioxidant activity of Yuliang are better than those of the other four producing areas.（3）Among them,the young leaves have the highest nutritional value,are more umami,and have significant characteristics of high potassium and low sodium.（4）50%shading rate is suitable for the growth of the Champereia malillana,and strong or weak light will inhibit its formation or weak light stress,affecting its growth.