龙牙百合的植株再生与遗传转化

以龙牙百合鳞片叶切块为外植体，通过多种培养基的比较试验，得出MS 2，4-D 2mg／L 6-BA 0．2mg／L是诱导愈伤的最佳培养基，MS 6-BA 1mg／L NAA 0．05mg／L是不定芽诱导及伸长的适宜培养基。MS N_AA2mg／L是生根的最佳培养基。本试验已建立了适用于龙牙百合遗传转化的快速高频再生系统。用携带有几丁质酶基因和β—1、3葡聚糖酶基因的工程菌，通过农杆菌介导法和基因枪转化法转化龙牙百合，经PCR和点杂交检测证明外源基因已经整合到植物染色体中。同时对农杆菌介导法和基因枪法进行比较，发现农杆菌介导法的转化率为16．7％，基因枪法的转化率为50％，因此可能基因枪转化法更适于龙牙百合的遗传转化。     

Steam explosion pretreatment used to remove hemicellulose to enhance the production of a eucalyptus organosolv dissolving pulp

The steam explosion (SE) pretreatment associated with the organosolv process was investigated to produce dissolving pulp from eucalyptus. Prehydrolysis Kraft (PHK) pulping was also done to produce viscose and acetate grade pulps as reference. The organosolv pulps were delignified in two steps with sodium chlorite. Viscose and acetate grade PHK pulps were bleached by OD₀(EH)D₁P and OD₀(EP)D₁PCCE sequences, respectively. Dilute acid-catalyzed (with acid addition) SE pretreatment dissolved more xylan than auto-catalyzed (no acid addition) SE pretreatment. Steam-exploded unbleached organosolv pulps showed lower residual lignin content and screened yield than unbleached organosolv pulps without SE pretreatment. Steam explosion pretreatment helped to decrease lignin content and damaged fiber length of unbleached organosolv pulps. The 1.0% H₂SO₄ organosolv pulp (organosolv dissolving pulp at bioconversion conditions) showed the highest reactivity. Even showing low viscosity for some applications, in general, the organosolv dissolving pulps produced in this study can be used for making lyocell fibers.     

Effects of density and resin content on the physical and mechanical properties of scrimber manufactured from mulberry branches

The silk industry in China produces a large amount of mulberry branches as by-product every year. Mulberry branches have high longitudinal toughness and good overall mechanical properties. However, these branches are incinerated because their utility in other industries is limited by their small size. This study determines the feasibility of manufacturing scrimber from mulberry branches by using cold pressing method, followed by thermo-curing with different densities and resin contents. Results show that density [ranging from (0.81–1.24) g/cm³] exerts a greater effect on the shear strength, modulus of rupture (MOR), and modulus of elasticity (MOE) than resin content (changing from 8 to 20 %). The increase rate slows down when the density exceeds 1.1 g/cm³ and the resin content reaches more than 12 %. The strength-to-weight ratio analysis shows that the MOR/density and MOE/density maximum at 1.02–1.10 g/cm³. The density and resin contents of mulberry scrimber with cold compress and heat setting can be set to 1.0–1.1 g/cm³ and at approximately 12 %, respectively. The mechanical properties of the product meet the maximum requirement indicated in the Chinese national standard for construction. Mulberry scrimber can be a very promising supplement for wood because of its good performance, abundant supply, and renewability.     

Expression of a scorpion toxin gene <Emphasis Type="Italic">BmKit</Emphasis> enhances the virulence of <Emphasis Type="Italic">Lecanicillium lecanii</Emphasis> against aphids

Lecanicillium lecanii has been developed as biopesticides and widely used in the biological control of several insects in agricultural practice. However, the poor efficacy has blocked its application. The genetic manipulation has been proved as a useful tool to improve the virulence of entomopathogenic fungus. In this study, a scorpion toxin gene (BmKit) from Buthus martensi was cloned and transferred into L. lecanii and then its resulting activity against cotton aphids (Aphis gossypii) was assessed. The results showed that the engineered strain BmKit-12 grew significantly quicker than WT in host insects. The median lethal concentration (LC₅₀) for BmKit-12 was 7.1-fold lower than that for WT, and the median survival time (LT₅₀) for BmKit-12 was reduced by 26.5 % compared with that for WT. Although the conidial yield was reduced by 31.4 % on insect cadavers, the mycelia growth, sporulation, and conidia germination of BmKit-12 on plates were not significantly different from WT. Considering the lower amount of mycelia for BmKit-12 in host insects in late growth stage (fungal sporulation stage), we think the expression of BmKit may not affect the capability of sporulation. In conclusion, the expression of BmKit gene can significantly enhance the pathogenicity of L. lecanii against cotton aphids in a relatively cost-effective way.     

Thermal diffusion in Masson pine wood

In order to analyze the effects of the temperature gradient on moisture movement during the highly intensive microwave-vacuum drying, thermal diffusion of Masson pine wood was studied. Internal distribution of temperature and moisture in Masson pine samples sealed by epoxy resin and aluminum foil was measured, the magnitude of thermal diffusion was calculated and the influencing factors of thermal diffusion were discussed. Results showed that with the transfer of moisture toward the low temperature in wood, opposite temperature and moisture gradient occurred. The initial moisture content （MC）, temperature and time are important factors affecting this process; the thermal diffusion is in proportion to wood temperature, its initial moisture and time. The temperature and distance from hot surface is strongly linearly correlated, and the relationship between MCs at different locations and distance from the hot end surface changes from logarithmically form to exponentially form with the increase in experimental time.     

Evaluation of potential land productivity in Wulushan,West China

The general situation of the total land resources in Wulushan, West China was studied by field investigations with the aid of a GIS software, called Region Manager. The current status of land use in Wulushan is described. The potential land productivity was evaluated by a fuzzy comprehensive method, We take each plot as a basic unit of evaluation on the basis of an index system of land resources in Wulushan which was developed from the investigation data. Evaluation of potential land productivity is the key part of land management. A guideline is presented in this paper for a proper utilization of the land resources and to develop the productive capacity of the land.     

Changes of plasma membrane H<Superscript>+</Superscript>-ATPase activities of <Emphasis Type="Italic">Glycine max</Emphasis> seeds by PEG treatment

The soybean （Glycine max） Heihe No. 23 is sensitive to imbibitional chilling injury. Polyethylene glycol （PEG） treatment can improve chilling tolerance of soybean seeds to a certain extent. The changes of hydrolytic ATPase in plasma membranes and H^＋-pumping responses in soybean seeds were investigated during PEG treatments. Effects of exogenous calcium and exogenous ABA on the hydrolytic ATPase were also examined in order to understand the mechanism of chilling resistance. Highly purified plasma membranes were isolated by 6.0% aqueous two-phase partitioning from soybean seeds, as judged by the sensitivity of hydrolytic ATPase to sodium vanadate. PEG treatment resulted in a slight increase of the hydrolytic ATPase activity in 12 h. Then the activity decreased gradually, but still higher than the control. The H^＋-pumping activity increased steadily during PEG treatment. Exogenous calcium had both activating and inhibiting effects on the hydrolytic ATPase, but the activity was inhibited in soybean seeds treated with exogenous ABA. Results suggested that PEG treatment, not the exogenous calcium and ABA, up-regulated H^＋-ATPase activities in soybean seeds.     

Productivity of kayu putih (Melaleuca leucadendron LINN) tree plantation managed in non-timber forest production systems in Java,Indonesia

Kayu putih oil, extracted from the kayu putih tree (Melaleuca leucadendron), is an important non-timber forest product (NTFP) in Indonesia. We compared productivity of kayu putih tree plantations among three different sites in East, Central, and West Java, Indonesia. Leaf-twig, and branch production per tree differed significantly among the three sites. Tree biomass production was highest at the site in West Java practicing tumpangsari (a form of shifting cultivation) of kayu putih with rice (Oryza sativa) on alluvial soils. Tree biomass production was lowest at the site in East Java, practicing tumpangsari of kayu putih with maize (Zea mays) and cassava (Mani- hot esculenta). At this site, tree biomass production increased with increasing stand age and low production was compensated by greater biomass yield of companion crops. Intermediate tree biomass production was observed at the site in Central Java where intercropping is only practiced for the first two years after plantation establishment. Production of tree biomass and kayu putih oil did not increase with increasing stand density, indicating that at a given site, high tree stocking did not lead to high production. Stand-level productivity of the plantations increased with increasing stand age and maximum productivity was attained at 15 to 35 years, after which productivity declined. This suggested unsustainable stand productivity as plantations increase in age.     

北京地区油松侧柏混交林树种间营养交互作用的矢量竞争分析(英文)

矢量竞争分析法是一种用于评价存在相同资源竞争的两种植物种之间的生长和营养交互作用的图形分析方法 .它基于矢量分析和线性分析 ,将代表生物量和营养吸收值的参数相对于无种间竞争的对照在一个两维的坐标系内表达为矢量并进行定位比较 .应用该方法对北京西山地区的 4 4年生人工混交林中油松和侧柏树种间生长和营养 (N ,P和K)吸收状况进行了比较和分析 .研究表明虽然混交有利于侧柏生物量的相对增加 ,但伴随有植物体内营养元素的相对亏缺 .相反 ,混交对油松生物量和高、径生长的抑制作用却伴随有营养元素吸收相对过剩 .以上结果表明矢量竞争分析可用于正确地揭示混交林树种之间营养交互作用     

Determining the origin of Al in the outflow from a forest watershed of a suburban forest in Japan by analysis of size distribution

This study clarified the origin of Al in spring water and stream water by analyzing the size distribution of Al of ground water, spring water, stream water, and soil extracts obtained by batch and column experiments using samples from a suburban secondary forest on granite bedrock in Aichi Prefecture. The high concentration of dissolved Al (Al_0.45; fraction through 0.45-μm filter) in water samples obtained from this study site was divided into completely dissolved and small colloidal forms (<0.20 μm; Al_0.20) and large colloidal forms (0.20–0.45 μm). More than 50% of dissolved Al (Al_0.45) in spring water existed in large colloidal form. By comparing the size distribution and concentration of various elements including Al in the samples from soil batch and column experiments, we suggest that the high concentration of Al in spring water is caused by the release of Al from surface soils when ground water emerges as spring water.