Comparison Of Chemical Composition Among Different Clones Of Populus And Cunninghamia Lanceolata For Breed Selection

In this paper,10 clones of poplar(Populus spp.)and 4 clones of Cunninghamia lanceolata were taken as samples.National standards for the determination of benzene alcohol extracts,holocellulose,?-cellulose and lignin,analysis of the chemical composition and radial variation of different clones of poplar and Cunninghamia lanceolata,the purpose of this study is to provide scientific data and theoretical support for the selection,cultivation and application of fast-growing wood poplar and Cunninghamia lanceolata.The main results are as follows:(1)Among the 10 clone poplars,the benzene alcohol extract of Populus deltoides CL.‘55/65'was the lowest(1.36%),and the contents of holocellulose(83.19%),?-cellulose(47.25%)and hemicellulose(35.94%)were the highest.the content of lignin(22.05%)is lower.In nine-year-old poplar,the content of benzene alcohol extract(1.31%)and lignin(22.98%)was the lowest,and the content of ?-cellulose(46.15%)was the highest.The overall radial variation was as follows: from the heart,the content of benzene alcohol extract increased at first and then decreased;the content of holocellulose increased at first and then became stable;the content of ?-cellulose gradually increased;the content of lignin and hemicellulose decreased gradually.The results of analysis of variance showen that different clones and growth rings had significant effects on the content of chemical composition(p < 0.01).For parents and offspring,except for the lignin content of Lin 46 has the transgressive segregation phenomenon,the contents of other chemical composition characters were between the parents.(2)Among the four clones of Cunninghamia lanceolata,Kai13 had the lowest content of lignin(32.72%)and the highest content of holocellulose(73.41%)and ?-cellulose(47.66%).The overall radial variation was as follows: from the heart wood,the content of benzene alcohol extract and hemicellulose decreased gradually;the content of lignin increased in the first decade and decreased in the next decade;the content of holocellulose and ?-cellulose increased gradually.The results of analysis of variance shown that except that there was no significant difference in hemicellulose content among clones,the effects of different clones and growth rings on other chemical composition contents were significantly different(p < 0.05).(3)The correlation between the chemical composition of poplar and Cunninghamia lanceolata shown that there were significant differences between poplar clones and growth rings and chemical compositions,and there was a very significant positive correlation between growth rings and holocellulose content and ?-cellulose content.it was negatively correlated with hemicellulose content and lignin content.The clones of Cunninghamia lanceolata only had a significant positive correlation with lignin content,and the correlation between growth ring and chemical composition was significantly different.The growth ring was significantly negatively correlated with the content of benzene alcohol extract and hemicellulose.It was significantly positively correlated with holocellulose content and ?-cellulose content,and significantly negatively correlated with holocellulose and ?-cellulose content,and positively correlated with hemicellulose content.(4)Populus deltoides CL.‘55/65' and Kai 13 clone were selected as excellent pulpwood clones.According to the analysis of overall radial variation,the rotation period of poplar can be selected at 7?8a,and that of Cunninghamia lanceolata at 14?16a.