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| 1 | Genetic variation of wood tracheid traits and their relationships with growth and wood density in clones of Pinus tabuliformis显示文摘To improve wood quality for pulpwood industries, it is important to examine not only wood density but also its components, especially tracheid characteristics.We studied genetic variations in the following tracheid traits by earlywood(EW) and latewood(LW): tracheid length(TL),double wall thickness(WT), radial lumen diameter(R_D1), tangential lumen diameter(T_D1), radial central diameter(R_D2), and tangential central diameter(T_D2).We also studied the relationship with the following growth traits: diameter at breast height(DBH), height(H), crown breadth south-north axis(NSC), crown breadth east–west axis(EWC), ring width(RW), latewood percentage (LWP), and wood density(WD).All sample materials were collected from a 33-year old clonal seed orchard of Pinus tabuliformis Carr.Genetic variation among clones was moderate for all tracheid traits, 9.49–26.03%.Clones significantly affected WT, R_D1, R_D2, T_D1, T_D2, and the two ratios WT/R_D1 and TL/T_D2 in EW but had no effects in LW.Clones significantly affected TL in LW but had no effects in EW.H2/C was higher in LW(0.50) than in EW(0.20) for TL, while H2/Cwas higher in EW(0.27–0.46)for other tracheid traits and the two ratios(TL/T_D2 and WT/R_D1) than in EW(0.06–0.22).WD and TL were significantly positively correlated, but WT and TL were negatively correlated both at individual and clone levels;all tracheid diameters and the four ratio values(EW_WT/R_D1, LW_WT/R_D1, EW_TL/T_D2 and LW_TL/T_D2), were strongly positively correlated with DBH, H,NSC, WEC and RW, and strongly negatively correlated with WD both at individual and clone levels.The most important variables for predicting WD were LW_TL,EW_WT and R_D1 in both EW and LW(r^2= 0.22).Selecting the top 10% of the clones by DBH would improve DBH growth by 12.19%(wood density was reduced by 0.14%) and produced similar responses between EW and LW for all tracheid traits: a reduction of0.94 and 3.69% in tracheid length and increases in tracheid diameters(from 0.36 to 5.24%) and double wall thickness(0.07 and 0.87%).The two ratios WT/R_D1 and TL/T_D2 across tissues(EW and LW) declined 0.59 and 4.56%,respectively.The decreased tracheid length and the ratio between tracheid length and diameter is disadvantageous for pulp production.The unfavorable relationship of tracheid traits with wood density indicate that multiple trait selection using optimal economic weights and optimal breeding strategies are recommended for the current longterm breeding program for P.tabuliformis. | Fangqun Ouyang Jianwei Ma Sanping An Junhui Wang Yuhui Weng | 2018 | Journal of Forestry Research2018,29,4: | 1 |
| 2 | Soil desiccation for Loess soils on natural and regrown areas显示文摘 | Li Wang Quanjiu Wang Sanping Wei Ming’an Shao Yi Li | 2008 | Forest Ecology and Management2008,,7: | 1 |
| 3 | Mixed-valence copper coordination polymers based on CuSCN or CuN_(3) as bridging motifs显示文摘Two novel mixed valence copper coordination polymers, [Cu(2-pac)2(CuN3)(H2O)]n (1) and [Cu(2-pac)2(CuSCN)2]n (2), have been prepared through hydrothermal synthesis and analyzed for structure determination, which exhibit two- and three-dimensional structures respectively. In complex (1), zigzag chains of [CuN3]n running parallel to the c direction are interconnected by Cu(2pac)2 to form a two-dimensional layer structure. In complex (2), the arrangement of μ-1,1,3 bridging thiocyanate ligand leads to the formation of ten-membered Cu-SCN- Cu-S-Cu-NCS rings, and each Cu atom is further linked by Cu(2-pac)2 to afford a three-dimensional configuration. | FAN Guang,GAO Shengli,CHEN Sanping,ZENG Minghua & XIE Gang Department of Chemistry,Northwest University,Xi’an 710069,China Department of Chemistry,Guangxi Normal University,Guilin 541000,China | 2005 | Science China Chemistry2005,48,z1: | 0 |
| 4 | Thermal decomposition of Pr[(C_(5)H_(8)NS_(2))_(3)(C_(12)H_(8)N_(2))]显示文摘The thermal behavior of the complex Pr[(C5H8NS2)3(C12H8N2)] in a dry nitrogen flow was examined by TG-DTG analysis. The TG-DTG investigations indicated that Pr[(C5H8NS2)3-(C12H8N2)] was decomposed into Pr2S3 and deposited carbon in one step where Pr2S3 predominated in the final products. The results of non-isothermal kinetic calculations showed that the decomposition stage was the random nucleation and subsequent growth mechanism (n =nential constant In[A/s] was 7.8697. The empirical kinetics model equation was proposed as f(α) =3/2(1-α)[-ln(1-α)]1/3. The X-ray powder diffraction patterns of the thermal decomposition products at 800℃ under N2 atmosphere show that the product can be indexed to the cubic Pr2S3 phase. The transmission electron microscopy (TEM) of the final product reveals the particle appearance of a diameter within 40 nm. The experimental results show that the praseodymium sulfide nanocrystal can be prepared from thermal decomposition of Pr[(C5H8NS2)3(C12H8N2)]. | GUO Pengjiang,JIAO Baojuan,CHEN Sanping,HU Rongzu,GAO Shengli & SHI Qizhen Department of Chemistry,Northwest University Shaanxi Key Laboratory of Physico-lnorganic Chemistry,Xi’an 710069,China Department of Mathematics,Northwest University,Xi’an 710069,China Xi’an Modern Chemistry Research Institute,Xi’an 710065,China | 2005 | Science China Chemistry2005,48,z1: | 0 |