Preliminary Studies On Seedling Growth And Energy Characters Of Poplar Clones Introduced From USA

The seedling growth and energy characters for 14 poplar clones introduced from USA were investigated.Through the comprehensive analysis on growth,wood properties and energy index,we primarily evaluated the fitness of these tested poplar clones.The main experimental results were as follows:1.There was a significant difference in growth for seeding stage among poplar clones.For all poplar clones,annual growth rhythm accorded with "S" curve both in seedling height and ground diameter.Clones 309-74,DN-34 and OP-367 were ranked as top three in the total biomass production.2.The net photosynthetic rate,transpiration rate,stomata conductance and Fv'/Fm' of the American clone were smaller than the CK,but the intercellular CO₂ concentration and Fv/Fm were higher than the CK.3.Both wood basic density and air dry wood moisture content had highly significant difference for different poplar clones.Clones 52-225,24-305 and 311-93 had bigger wood basic density,while Clones NM6 and 306-45 had bigger air dry wood moisture content.4.There were highly significant differences in the crude fibre content,alcohol benzene extractive content,lignin content and ash content among different poplar clones.Overall,the stem crude fibre content,bark alcohol benzene extractive content and ash content of the American clone were higher than theCK clone,but the stem lignin content was smaller than the CK.5.Highly significant differences in C,N and S contents were founded among different components for tested poplar clones.As a mean,C content was about 50% in the poplar clones,.In different American poplar clone,the content of Ca,Si,K,P,Mg was higher than the CK,while Cu,Fe,Na was lower than the CK.6.The AFCV and the GCV had significant or very significant difference both in different components and different clones.Overall,the American clones NM6,24-305,311-93,309-74 had the higher GCV than the other introduced poplar clones.7.By the factor analysis and cluster analysis,the study showed that clones 311-93,DN-34,309-74 and OP-367 displayed the quick growth and the high gross caloricvalue among introduced poplar clones,which appeared better comprehensive characters for woody bioenergy.