Fu Xiangxiang

Variation of microfibril angle and its correlation to wood properties in poplars

The microfibril angle of seven poplar clones was determined by using X-ray diffraction technique. Microfibril angle, wood basic density, fiber length, fiber width and cellulose content were assessed for every growth ring at breast height for all sample trees. Significant variation in microfibril angle was observed among growth rings. Mean microfibril angle (MFA) at breast height varied from 7.8° to 28° between growth rings with cambial age and showed a consistent pith-to-bark trend of decline angles. Analysis of variance also indicated that there were significant differences in wood basic density, fiber length, fiber width and cellulose content between the growth rings, which had an increasing tendency from pith to bark. Correlations between MFA and examined wood properties were predominantly large and significant negative (α=0.01), and the coefficients were −0.660 for cellulose content, −0.586 for fiber length, −0.516 for fiber width and −0.450 for wood basic density, respectively. Regression analysis with linear and curve estimation indicated that a quadratic function showed the largestR2 and the least standard error for describing the relationships between microfibril angle and measured wood properties, and the correlation coefficients were over −0.45 (n=125). The results from this study suggested that microfibril angle would be a good characteristic for improvement in the future breeding program of poplars.

Identification of seeds of Pinus species by Microsatellite Markers

The 276 pair-primers (nuclear and chloroplast microsatellite) developed from seven species of Pinaceae were selected and identified for cross-species transferability to tenPinus species (P. massoniana, P. kesiya, P. tabulaeformis, P. densiflora, P. thunbergii, P. caribaea, P. taeda, P. yunnanensis, P. densata, P. sylvestris) belonging to Sect.Pinus by BSA (bulked segregate analysis) method. The results showed that 23 of 276 (8.0%) markers were successful to have amplification product in ten species, and 5 of 23 (21.7%) were polymorphic cross species and lack of polymorphic within species. Eight of 10Pinus species were identified by using single primer, two and more combination of primers, but there were still no effective SSR primers for identifying other 2 species (P. kesiya andP. densata).

Effects of Ca2+ concentrations on accumulations of mineral elements in the components ofPteroceltis tatarinowii

The bark ofPteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca2+ concentrations on the accumulation of mineral elements in the bark, leaf and root ofPteroceltis tatarinowii were studied under controlled conditions. The types of Hoagland nutrient solution with three Ca2+ concentrations levels (200, 400 and 600 μg·g−1) and a control (without Ca2+ were designed to culturePteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca2+ concentrations (200, 400, 600 μg·g−1), and the order of the Ca content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g−1 Ca2+ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200 and 400 μg/g Ca2+ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca2+ concentrations, especially in the bark, and their accumulation trend followed the order of leaf>root>bark. K content in the bark treated with 600 μg·g−1 Ca2+ concentrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200μg·g−1 and 400μg·g−1 Ca2+ concentrations respectively; Mg content in the bark treated with 600μg·g−1 Ca2+ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 μg·g−1 Ca2+ concentrations respectively. Compared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca2+ concentrations and their contents were in the order: root>leaf>bark. Based on the results of this study, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil.