Studies On Biological And Physicochemical Characteristics Of Dendrocalamus Farinosus From The Different Genotypes

In this study,cultivated Dendrocalamus farinosus?ZPX?and other different genotypes of D.farinosus obtained by somatic mutation were used as materials.The biological characteristics,biomass,anatomical structure of bamboo shoots,chemical composition of culm,paper-making properties,fiber properties,gene expression and genetic diversity of bamboo were studied.The main results are as follows:Average of plant height from genotype 212-A was 25%higher than that of the ZPX.The DBH?diameter at breast height?of genotypes 61-B,2-2 and 212-A was larger than ZPX,which were 17.6%,28.4%and 55.7%respectively.The longest internode length of genotypes 126-2-A,52-B,35-B and 5-3 was longer than ZPX?about 45 cm?,approaching 50 cm.There were obvious differences in the biological characteristics of different genotypes of D.farinosus,such as the color of bamboo sheath,the thickness of waxy layer of new bamboo,the color of clum,the color of bamboo sheath hair,the characteristics of culm ring and the distribution of bamboo sheath hair.According to these differences,37 genotypes of D.farinosus can be divided into eleven groups.By observing the anatomical structure of bamboo shoots of 13 genotypes,it was found that the vessel diameter of all other genotypes of D.farinosus were larger than ZPX,except 129-B.According to the cluster analysis of culm wall thickness,thirty-three genotypes of D.farinosus are divided into two groups?thin clum wall group and thick culm wall group?.Fitting models of dry weight?Y?and breast diameter?X?were established,respectively.Thick clum wall group fitting model was quadratic equation,the equation was Y=24.331+1.605X²-3.701X.Thin clum wall group fitting model is power equation,the equation was Y=0.306X^2.381,R² was 0.942 and 0.927,respectively.The average dry weight per plant of 12 genotypes,such as 30-A,212-A,214,30-B,61-B,2-2,66,40-1-B,126-A,90-3-B,14-B and 90-1,are significantly higher than that of ZPX,and the average dry weight of 212-A was 2 times higher than that of ZPX,while genotypes 29-B,34-B,5-2,5-3,120-A,35-B,9-A and 19-A were significantly lower than ZPX in dry weight.There were some differences in fiber morphology among different genotypes of D.farinosus.Genotypes 29-A,30-B,61-B and 2-2 had longer fibers length and bigger fiber aspect ratio than ZPX.And genotypes 29-A,30-B were significantly lower fine fiber content than ZPX,their good fiber morphology was excellent and suitable for pulping and papermaking.The cellulose content of different genotypes of D.farinosus ranged from 40%to60%.The cellulose content of 29-A,212-A,214,40-2,215,126-2-A,61-B and 2-2was significantly higher than that of ZPX.The lignin content of 40-2,126-2-A,2-2,208-2-B,101-3-B,34-B,5-3,9-A was lower than that of ZPX.The properties of sulfate pulp in D.farinosus are different from the different genotypes.The pulp properties of 61-B,212,30-B and 126-A meet the requirements of national high-quality sulfate pulp products,and the yield of good pulp was3.31%-5.72%higher than that of ZPX.The pulp properties of 101-2-B,90-3-B,214,64-A sulfate pulps meet the requirements of national first-class products,and the yield of good pulp was 1.45%-9.25%higher than that of ZPX.Factor analysis showed that90-3-B,129-B,212-A,126-A and 64-B had better pulping performance and The genotypes 61-B,30-B and 90-3-B had better paper properties.The expression levels of cellulose synthesis related genes in the different genotypes of D.farinosus at shoot stage were detected.The relative expression level of DfCesA3 gene in 129-B,64-A,120-A,90-3-B and 61-B was 2-4.5 times higher than that of ZPX;the relative expression level of DfCesA4 gene in 126-A and 129-B was significantly higher than that of ZPX;the relative expression level of DfCesA7gene in 126-A,129-B,120-A and 30-B was significantly higher than that of ZPX.The correlation analysis showed that the expression levels of DfNAC2 and DfMYB3 were significantly positively correlated,the length of fibers in bamboo stalks was significantly negatively correlated with DfNAC2,and the density of vascular bundles in bamboo shoots was significantly positively correlated with DfCesA7.By screening 73 EST-SSR primers,21 pairs of SSR primers with polymorphic bands were obtained.The polymorphic ratio of 21 pairs of SSR primers was 28.8%.A total of 85 polymorphic bands were obtained among 37 genotypes of D.farinosus.The average effective bands of each pair of primers were 4.Two markers?L1 and L26?associated with culm dry weight and DBH were found by correlation analysis between traits and SSR band phenotypes.