松脂液加氢反应的研究

松脂液在催化剂存在下加氢，可同时获得氢化松香与蒎烷，所得氢化松香颜色浅，质量好。采用低温活性好的触媒，在较低温度及合适压力下，可使蒎烷中顺式与反式之比达到７．５￣８．５，精馏后可达９￣１０，从而满足了香料工业的要求。加氢产物用气－质联用仪分析，表明脂液中对异丙基甲苯及分子量较大的烯烃（长叶烯及石竹烯等）未参与加氢反应。蒎烷可采用脂液冷却结晶法，使其循环使用。     

分形理论在植物根系结构研究中的应用

根系结构是影响植物生长的重要因素，本首次探讨了分形模型在植物根系结构研究中的应用，并以马尾松为例分析了马尾松根系结构与分形维数的关系，结果表明：马尾松细根含量越低，根桩含量越高，生长越好，分形维数越小，根系结构的各级含量，根桩量以及胸径，树高与植物根系结构分形维数之间存在显的回归关系，分形模型可以应用于植物根系结构特征的研究，从而为植物根系结构研究提供新方法。     

云南景谷地区松脂研究的现状与对策

云南省景谷地区具有丰富的思茅松资源，盛产松脂，为此开展了高产脂种源培育等试验研究，对松树进行多种采脂方法的研究，调查各种采脂方法的实用性，并不断开发新的采脂方法。     

阔叶红松林及其次生杨桦林优势树种间氮素营养关系的研究

为了探讨阔叶红松林演替与原始阔叶红松林稳定性中存在的Ｎ素机制作用，１９９１年７月，在长白山（北坡）自然保护区（海拔７４０ｍ），应用近几年建立的化学和生物化学分析方法，通过分析土壤Ｎ素及有效形态ＮＯ３－Ｎ、ＮＨ４－Ｎ的供应和林木的Ｎ素吸收利用状况，对原始阔叶红松林及破坏后形成的两个不同龄级的杨桦林中优热树种林木的Ｎ素营养状况及树种间Ｎ素营养关系进行了研究。结果表明：１．各样地土壤中Ｎ素营养状况及树种     

Charcoal and smoke extract stimulate the soil microbial community in a highly weathered xanthic Ferralsol

The influence of charcoal and smoke condensates (pyroligneous acid, PA) on microbial activity in a highly weathered Amazonian upland soil was assessed via measurements of basal respiration (BR), substrate-induced respiration (SIR), and exponential population increase after substrate addition. PA extracts are commonly used for fertilizer or as pest control in Brazil, where phosphorus (P) availability and nitrogen (N) leaching are among the most severe limitations for agriculture. Microbes play an important role in nutrient cycling and solubilizing of phosphate. BR, microbial biomass, population growth and the microbe's efficiency (expressed by the metabolic quotient) increased linearly and significantly with increasing charcoal concentrations (50, 100 and 150 g kg⁻¹ soil). Application of PA caused a sharp increase in all parameters. We suppose that the condensates from smoke contain easily degradable substances and only small amounts of inhibitory agents, which could be utilized by the microbes for their metabolism.     

永春县马尾松摘梢造林试验效果分析

通过对马尾松摘梢与无摘梢造林成活率、胸径生长、高生长情况进行调查分析,结果表明:摘梢造林平均成活率比无摘梢高出28%,摘梢造林与无摘梢造林对马尾松的胸径、树高生长影响均无显著差异,坡位对马尾松的胸径、树高生长影响极显著差异。     

FT-IR study of the changes in carbohydrate chemistry of three New Jersey pine barrens leaf litters during simulated control burning

Low intensity control burns are a standard fuel reduction management tool used in pine barrens ecosystems. Periodic disturbances through fire can be an important influence on the cycling of nutrients within the ecosystem. Previous studies have shown that the inorganic chemistry of leaf litter residues differs with increasing temperature. Our study compared chemical changes in white oak (Quercus alba), pitch pine (Pinus rigida) and black huckleberry (Gaylussacia baccata), characteristic of the New Jersey pine barrens, during thermal decomposition using FT-IR spectroscopy. Three replicates of senescent leaf material were ground and separately heated for 2 h at: 100, 200, 300, 400 and 550 °C. These temperatures are representative of the range seen in fuel reducing prescribed burns in the pine barrens. Unburned litter of each species was used as a control. An optimization process using varying amounts of KBr and oak litter was performed to develop favorable FT-IR spectral conditions for a sample to KBr ratio of 0.75%. Chemometric analysis of the FT-IR spectra using principal component analysis (PCA) was used to analyze the changes in carbohydrate chemistry of each litter plant species (leaf litter species) at each temperature. In general, it appears that there is clear separation of leaf litter species at the different combustion temperatures. Infrared spectroscopy illustrated that all three species shared wavenumbers characteristic of the primary components of leaves such as cellulose, lignin and hemicellulose. Results from the PCA indicated separation of litter species and species by combustion temperature. PC axis 1 corresponds to the effects of temperature on leaf litter species and PC axis 2 separates the leaf litter species. At the low temperatures (control-200 °C), oak, pine and huckleberry litter species separated from each other. Wavenumbers that contributed to the separation of species at low temperatures belonged to functional group stretching frequencies of outer surface waxes, basic sugars, fatty acids and aldehydes. It appears that oak had more IR bands specific to suberin content. Convergence of these species occurs at 300 °C. Complexity of chemical composition decreases at this particular temperature as is shown by the decrease in wavenumber richness when compared to litters at low and high temperatures. Oak, pine and huckleberry had similar IR spectra showing bands belonging to outer surface wax content, pectin, lignin and hemicellulose. With increasing temperatures (400-550 °C), differences between litter species increased slightly. Plant material was reduced to similar composition due to thermal decomposition, which consisted of inorganic materials such as carbonate, phosphate and sulfate ions and possible fused aromatics.     

Culture-dependent and culture-independent microbial investigation of pine litters and soil in subtropical Australia

Background, aim, and scope  Forest plantations, widely grown for wood production, involve the selective promotion of single-tree species or replacement of natural species by exotic tree species. Slash pine (Pinus elliottii) has been chosen for reforestation of infertile sandy soils in southeast Queensland, Australia. These exotic pine plantations minimize soil and water losses and are important scientific study sites. The soil environment of these plantations, though devoid of sufficient nutrients, organic carbon and other factors, harbors innumerable bacteria that may play a crucial role in maintaining soil quality and ecosystem functions. These soil microorganisms also have the potential for use as sensitive biological indicators to reflect environmental changes. It is therefore essential to understand the interrelationships among bacterial communities and their environment by assessing their structural and functional diversity and their responses to disturbances. The main aim of our investigation was to determine the diversity of bacterial communities in forest litters and soil during the forest leaf litter decomposition using culture-dependent and culture-independent techniques. Materials and methods  A 25-cm (diameter) × 40-cm core sample was collected and fractionated into three subsamples designated E1 (L leaf litter layer), E2 (F leaf litter layer), and E5 (0–10 cm soil layer). Both culture-dependent and culture-independent methods were applied in this study. In the culture-independent study, a strategy of whole-community DNA extraction, polymerase chain reaction (PCR) amplification followed by cloning and 16S rDNA sequence analysis was used; for culture-dependent study, the strategy included sample plating and bacteria isolating, DNA extraction, PCR amplification, and 16S rDNA sequence analysis. The diversity similarities between two bacterial communities and two methods are quantified using Jensen–Shannon divergence. Results  From culture-dependent study, 336 colonies in total were isolated and grouped from the three subsamples, and the 16S rRNA sequence analysis from a representative isolate from each morphogroup (21 isolates) indicated that they belonged to the phyla Actinobacteria, Firmicutes, and Proteobacteria. Culture-independent assessment based on 16S rRNA gene library comprising 194 clones revealed that members of the phylum Actinobacteria were absent in the culture-independent studies. Clones in libraries from E1 consisted exclusively of members of the Firmicutes. The majority of clones from E2 were related to Firmicutes (79%) and Proteobacteria (21%). Clones derived from E5 were mostly affiliated with Acidobacterium (42%), followed by unclassified bacteria (27%), Verrucomicrobiales (12%), Proteobacteria (11%), and Planctomycetes (8%). Discussion  This study showed that bacterial culturabilities in different fractions of leaf litters were similar, and both of them were higher than the bacterial culturability in the soil. Unculturable bacterial diversity in the soil, however, was much higher than the leaf litter bacterial diversity. The bacterial diversity on the top layer of leaf litters was slightly less than that on the bottom layer of leaf litters. This might indicate that forest soils are a more complex environment than leaf litters are and also that they might inhabit more unculturable microorganisms in the forest soils, which would need to be further investigated. The leaf litter layer samples also demonstrate the significant difference between the bacterial community diversity discovered by these two methods in this study. The information provided by assessing the different fractions of leaf litters and forest soil has improved our understanding of the bacterial community distributions within the forest soil and the above-leaf litters in an exotic pine plantation of subtropical Australia. Conclusions  This study represents the first attempt to examine the bacterial community in the different fractions of forest leaf litters and soil in subtropical Australia. The data from this study show that the 16S rDNA clone libraries provided more comprehensive phylogenetic diversity in the soil and leaf litter samples than the culture collections provided, and both the culture-dependent and culture-independent studies revealed that the bacterial diversity present in the leaf litters was very different to that present in the soil. The comparative analysis of bacterial communities in different fractions of leaf litters and soil samples has also provided important baseline information about the bacterial diversity and composition in the exotic pine forest plantations. Recommendations and perspectives  The experimental data provided important information on the bacterial diversity in forest leaf litter and soil samples, though additional surveys and comparisons at different locations would be needed to further characterize. In addition, combined methods that can provide different parts of information on bacterial diversity are encouraged to be used in bacterial community study. The established libraries of diverse 16S rRNA gene fragments from slash pine leaf litters and forest soil can be used to construct specific DNA primers and probes to target bacterial groups of interest. It may then be possible to study the ecology of these bacterial communities and the role of specific bacterial groups that contribute to the many interesting properties of these environments.     

松属种间嫁接对松脂化学组成的影响

通过对光松、萌芽松或展松与湿地松嫁接后松树的松脂化学组成的研究，探讨松属种间嫁接对松脂化学组成的影响。结果发现作为接穗的光松、萌芽松和展松的松脂化学特下基本上不变，不具有其砧木－湿地松松脂的特征。     

华山松腐烂病发生危害与相关因子的初步研究

 调查研究表明:华山松腐烂病的发生危害与树龄、混交比、郁闭度等11方面的因子有关,将有助于华山松腐烂病发生、发展规律的研究和防治工作的开展。