Ultrastructural and Extracellular Protein Changes in Cell Suspension Cultures of Populus euphratica Associated with Low Temperature-induced Cold Acclimation

Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A cell suspension culture was initiated from callus derived from plantlets of Populus euphratica. Cold acclimation was induced (LT50 of-17.5 ℃) in cell suspension at 4-5 ℃ in the dark for 30 days and the freezing tolerance increased from LT50 of-12.5 ℃ in nonacclimated cells to LT50 of-17.5 ℃ in cold-acclimated cells. Microvacuolation, cytoplasmic augmentation and accumulation of starch granules were observed in cells that were cold-acclimated by exposure to low temperatures. Several qualitative and quantitative changes in proteins were noted during cold acclimation. Antibodies to carrot extracellular (apoplastic) 36 kD antifreeze protein did not cross react on immunoelectroblots with extracellular proteins in cell suspension culture medium of Populus euphratica, indicating no common epitopes in the carrot 36 kD antifreeze protein and P euphratica extracellular proteins. The relationship of these changes to cold acclimation in Populus euphratica cell cultures was discussed.     

Evolution of soil microbial biomass in restoration process of Robinia pseudoacacia plantations in an eroded environment

Vegetation recovery is a key measure to improve ecosystems in the Loess Plateau in China. To understand the evolution of soil microorganisms in forest plantations in the hilly areas of the Loess Plateau, the soil microbial biomass, microbial respiration and physical and chemical properties of the soil of Robinia pseudoacacia plantations were studied. In this study, eight forest soils of different age classes were used to study the evolution of soil microbial biomass, while a farmland and a native forest community of Platycladus orientalis L. were chosen as controls. By measuring soil microbial biomass, metabolic quotient, and physical and chemical properties, it can be concluded that soil quality was improved steadily after planting. Soil microbial biomass of C, N and P (SMBC, SMBN and SMBP) increased significantly after 10 to 15 years of afforestation and vegetation recovery. A relatively stable state of soil microbial biomass was maintained in near-mature or mature plantations. There was an increase of soil microbial biomass appearing at the end of the mature stage. After 50 years of afforestation and vegetation recovery, compared with those in farmland, the soil microbial biomass of C, N and P increased by 213%, 201% and 83% respectively, but only accounting for 51%, 55% and 61% of the increase in P. orientalis forest. Microbial soil respiration was enhanced in the early stages, and then weakened in the later stage after restoration, which was different from the change of soil organic carbon. The metabolic quotient (qCO₂) was significantly higher in the soils of the P. orientalis forest than that in farmland at the early restoration stage and then decreased rapidly. After 25 years of afforestation and vegetation recovery, qCO₂ in soils of the R. pseudoacacia forest was lower than that in the farmland soil, and reached a minimum after 50 years, which was close to that of the P. orientalis forest. A significant relationship was found among soil microbial biomass, qCO₂ and physical and chemical properties and restoration duration. Therefore, we conclude that it is possible to artificially improve the ecological environment and soil quality in the hilly area of the Loess Plateau; a long time, even more than 100 years, is needed to reach the climax of the present natural forest. __________ Translated from Acta Ecologica Sinica, 2007, 27(3): 909–917 [译自: 生态学报]     

仙鹤草多糖的提取及部分理化性质

以多糖提取率为指标,采用L9（3^4）正交实验设计对仙鹤草多糖的提取工艺条件进行优化,并采用脱蛋白与DE-52纤维素离子交换柱层析法对仙鹤草多糖进一步分离纯化．同时对多搪的性质进行分析鉴定。实验结果表明,仙鹤草多糖的最佳提取工艺为：浸提温度为80℃,浸提时间12h,料液比1：15．在此条件下仙鹤草多糖提取率为2．15％,浸提温度是影响得率的主要因素。纯化后的仙鹤草多糖组分HAPI、HAPII多糖含量分别为70．08％、78．80％。     

高温胁迫下14个银杏品种的耐热性

以我国银杏主产区14个银杏栽培品种为材料,利用生理生化测定及SPSS统计分析对其耐热性进行研究。结果表明:持续7d45℃的高温胁迫能够有效区分不同银杏品种耐热性;生理生化测定结果的系统聚类与主成分分析能够对不同银杏栽培品种的耐热性进行有效评价。苏农佛手、郯城300和新村16号为热敏感型,耐热型较差,洞庭皇1号、郯城马铃2号和大龙眼为耐热型,耐热性较强。银杏栽培品种耐热性与核形的相关性不大。     

Predicting the distributions of suitable habitat for three larch species under climate warming in Northeastern China

The larch (Larix) genus is the most important species group in the forest ecosystems in Northeastern China, occupying about 25% of the forest areas. The high tolerance to coldness and relatively fast growth rate make this genus the main species group for forestation. According to the predictions of the global circulation model CGCM3, temperature could rise by 2–4 °C over the next 100 years. Few studies have been conducted on the response of larch species to climate warming in Northeastern China. Such studies are becoming increasingly needed due to the economic and ecological significance of this genus. This paper studies the potential distribution ranges of three larch species under the current and the warming climate conditions. A new classification and regression tree technique, Random Forest, was used to investigate the potential distributions of three larch species, based on 18 environmental variables which reflect the climate, topography and soil conditions of Northeastern China. The results showed that the biological coldness index (BCI) is the most important factor for Dahurian larch, annual precipitation (AP) is the most important factor for Korean larch and elevation (DEM) is the most important factor for Prince Rupprecht larch.     

茶秆竹林叶面积指数与生物量关系的研究

为探索茶秆竹叶面积指数与生物量的关系，本文应用多种数学模型对茶秆竹林叶面积指数与年龄、胸径、立竹密度、留枝盘数等因子的相关性进行回归分析，结果表明，叶面积指数与生物量紧密相关，当叶面积指数为7．47时，茶秆竹生物量最大。本文同时建立了叶面积指数与胸径、立竹密度的关系表，以为生产提供一定的参考依据。     

广西牡竹属两新种

发表牡竹属二新种——清甜竹、融安黄竹     

快速测定活性炭对环己烷吸附荷量的方法：迎头色谱穿透曲线法

长期以来都是通过测定四氯化碳荷量或吸苯率，来评价用于气相吸附活性炭的吸附性能。由于四氯化碳是剧毒试剂，苯是致癌物质、所以本文改用环己烷作为吸附质，通过测定各种活性炭对环己烷的吸附等温线，详细讲话他环己烷荷量作为评价活性炭吸附性能的条件。并介绍了快速测定活性炭对环己烷的吸附荷量的迎头色谱穿透曲线法。     

北京低山地区土壤酶活性与土壤理化性质的关系

通过对北京低山地区土壤的理化性质和脲酶、过氧化氢酶以及多酚氧化酶的分析，探讨了供试土壤中３种酶活性状况及其与土壤理化性质的关系。研究结果表明：３种土壤酶活性均表现出随土壤深度增加而降低的规律性；３种土壤酶活性间具有良好相关性，显示了３种酶在土壤生物化学过程中的共性关系；土壤酶活性同多种土壤性质呈现良好相关性，其中，土壤有机质含量和土壤全氮量对酶活性影响最大。     

木材干燥窑的保温性与节能分析

常规砖砌壳体木材干燥窑热能消耗大，节能潜力很大，本文通过对窑体保温材料和大门密，保温性能改进措施的分析及应用，结果表明，壳体热损失减少６０％以上，总能源可减少１２％以上，节能效果显著，此外对用热油作为导热介质，也探讨了其节能的可行性。