减轻林业税费促进林业健康发展

针对我国现行林业税费存在的问题,如:林业税费种类繁多、比重大、政策执行不规范、不完善等,提出了相应的对策和建议,阐明应减轻林业税费,以促进林业健康发展.     

Predicting equations of main factors affecting regional climate in the "Three-North" Protective Forest Area

lntroductionInordertosolvetheseriousecologicaIproblemwefacedandimprovethephenomenonoflanddesertifi-cationinthenorthareaofChina.ChinahasbeguntoconstructtheThree-NorthProtectiveForestSystemsince1978.Withthehardworkoftwentyyears,itistold"Thegreatestecologicalprojectoftheworld"and"ThegreengreatwaIl".AIthoughthecountryinvestedIotsofcapitaItobuiIdtheThree-Northshelter-forestsystemthroughmanywayssuchasThree-Northspecialinvestment,financeappropriatefunds,finan-cialloansandtakeoutfundsforbringup…     

甘蔗渣制造活性炭的研究和试生产

本文研究了甘蔗渣用氯化锌法生产活性炭的可能性,探索最佳工艺条件和进行工业规模生产的可行性。实践表明,甘蔗渣是制造高脱色力糖用炭的优良原料之一,甘蔗渣用化学法生产活性炭操作工艺简单,产品质量优良,糖用炭的主要指标达到或超过林业部颁LY216-79一级品标准。     

杉木人工林树上宿存枯死枝、叶在冠层与在枯枝落叶层分解的比较研究

杉木枯死枝、叶有在树上宿存多年的特性。江西分宜大岗山地区一立地指数 14 ,林龄 13a ,保留密度 2 60 0株·hm- 2 的 1代林 ,树上宿存枯死枝、叶总量达 4 10 8 0kg·hm- 2 ,相当枯枝落叶层生物量的 3 5 4 %。树上宿存枯死枝、叶在冠层的分解速度 ,与置于枯枝落叶层的分解速度的测定结果表明 ,后者比前者快得多。说明在杉木林生长急需养分的速生期和杆材期 ,将树上宿存枯死枝、叶适时地打落于地表 ,使其在枯枝落叶层分解 ,与挂在冠层上的分解相比 ,对林木营养作用不同 ,前者比后者能及时、更多地提供养分。树上宿存枯死枝、叶在林冠下部由低到高呈 4层分布。鉴于各层死亡时间不同 ,经受的分解时间和雨水淋溶的强度也相异 ,其在树冠上的分解速度是分层测定的 ,上下层差异较大。在枯枝落叶层的分解速度也分层测定 ,上下层的差异较小。在枯枝落叶层分解时 ,本实验 1年间枝的各层分解量之和是树冠上分解时的近 2 3倍 ,叶为 5 4倍。在枯枝落叶层分解时 ,1年间各层枝、叶 ,营养元素归还量之和是树冠上分解时的 3 5倍。速生、杆材期 ,适时地将树上宿存枯死枝、叶打落于地表 ,对连栽杉木林长期生产力的保持更是有积极作用     

湖南棉花品种（系）铃病抗性分析

以2016年参加湖南省棉花品种区域试验和机采棉品种区域试验的参试品系及育种单位提供的新品系、抗病对照、感病对照共26个品种（系）为研究对象，调查各品种（系）铃病发生情况。聚类分析结果将26个供试材料分成了3类，第Ⅰ类为铃病发生较轻型，铃病发生率为2.9%～6.7%，平均为4.7%；第Ⅱ类为铃病发生中等型，铃病发生率为8.0%～14.4%，平均为11.2%；第Ⅲ类为铃病发生较重型，铃病发生率为16.7%。表明湖南省的品种（系）对铃病病原菌的抵抗力存在显著差异，建议在今后的品种选育中加强对铃病抗性好的棉花新品种的选育。     

转基因抗虫棉品种邯6203的选育及栽培技术

主要介绍棉花品种邯6203的选育过程、特征特性、产量、纤维品质、抗病虫性及栽培技术措施。     

Enzymatic treatment on cotton fibers: degradation kinetics of pectin and influence of shape change on adsorption

Alkaline pectinase was one of the most effective enzymes to treat cotton as alternative agent to replace the conventional alkaline method. Removal of pectin and cutin was considered the explanation for improvement of wettability as well as water adsorption on cotton fiber. However, degradation kinetics of pectin is unclear, and the influence of fiber shape on property changes after enzymatic treatment was ignored. The main objective of this work was to reveal interactions between pectinase and cotton fiber for mechanism study. A heterogeneous catalysis kinetic equation, which is associated with Langmuir adsorption model and enzyme deactivation, was used to describe the heterogeneous catalysis. The enzymatic process conditions were optimized. Raw cotton fibers, pectinase-treated and alkali-treated fibers were characterized by impurities content determination, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Mechanism of water adsorption enhancement on treated fibers was discussed. In addition to elimination of the outer impurities, flat fibers with less twist and shape changes of lumen were also obtained to ensure better accessibility and water adsorption after enzymatic treatment.     

Analysing taxonomic structures and local ecological processes in temperate forests in North Eastern China

Background

One of the core issues of forest community ecology is the exploration of how ecological processes affect community structure. The relative importance of different processes is still under debate. This study addresses four questions: (1) how is the taxonomic structure of a forest community affected by spatial scale? (2) does the taxonomic structure reveal effects of local processes such as environmental filtering, dispersal limitation or interspecific competition at a local scale? (3) does the effect of local processes on the taxonomic structure vary with the spatial scale? (4) does the analysis based on taxonomic structures provide similar insights when compared with the use of phylogenetic information? Based on the data collected in two large forest observational field studies, the taxonomic structures of the plant communities were analyzed at different sampling scales using taxonomic ratios (number of genera/number of species, number of families/number of species), and the relationship between the number of higher taxa and the number of species. Two random null models were used and the “standardized effect size” (SES) of taxonomic ratios was calculated, to assess possible differences between the observed and simulated taxonomic structures, which may be caused by specific ecological processes. We further applied a phylogeny-based method to compare results with those of the taxonomic approach.

Results

As expected, the taxonomic ratios decline with increasing grain size. The quantitative relationship between genera/families and species, described by a linearized power function, showed a good fit. With the exception of the family-species relationship in the Jiaohe study area, the exponents of the genus/family-species relationships did not show any scale dependent effects. The taxonomic ratios of the observed communities had significantly lower values than those of the simulated random community under the test of two null models at almost all scales. Null Model 2 which considered the spatial dispersion of species generated a taxonomic structure which proved to be more consistent with that in the observed community. As sampling sizes increased from 20 m × 20 m to 50 m × 50 m, the magnitudes of SESs of taxonomic ratios increased. Based on the phylogenetic analysis, we found that the Jiaohe plot was phylogenetically clustered at almost all scales. We detected significant phylogenetically overdispersion at the 20 m × 20 m and 30 m × 30 m scales in the Liangshui plot.

Conclusions

The results suggest that the effect of abiotic filtering is greater than the effects of interspecific competition in shaping the local community at almost all scales. Local processes influence the taxonomic structures, but their combined effects vary with the spatial scale. The taxonomic approach provides similar insights as the phylogenetic approach, especially when we applied a more conservative null model. Analysing taxonomic structure may be a useful tool for communities where well-resolved phylogenetic data are not available.