Seedling establishment ofPolygonum cuspidatum andPolygonum weyrichii var.alpinum at high altitudes of Mt Fuji

Seedling establishment ofPolygonum cuspidatum (Seib. et Zucc.) andPolygonum weyrichii (F. Schmit) var.alpinum (Maxim.), dominant early-successional species in a volcanic gravel area on Mt Fuji, Japan, was compared for current-year seedlings at 2500 m a.s.l. The rate of survival in the first winter after germination at 2500 m was 2% and 24% forP. cuspidatum andP. weyrichii seedlings, respectively, and correlated with the upper distribution limit of each (2500–2600 m forP. cuspidatum; 3200–3300 m forP. weyrichii). The critical size for survival was 12 mg dry weight for overwintering current-year seedlings of both species. At 2500 m, the percentage of seedlings that attained the critical size for survival at the end of the first growing season was 19% and 85% forP. cuspidatum andP. weyrichii, respectively. Growth curves indicated that the larger-seeded characteristic ofP. weyrichii contributed to larger end-of-season size and resulted in higher rate of seedling survival at 2500 m, compared with smaller-seededP. cuspidatum. Current-year seedlings ofP. weyrichii, at least up to 3250 m, attained the first year annual growth critical for overwintering and therefore for successful seedling establishment, due to the large-seeded characteristic. At the top (3770 m) beyond the upper distribution limit ofP. weyrichii, most seedlings raised artificially failed to attain the critical size for survival in the first growing period due to the reduced growing period. Failure of seedling establishment would thus appear to restrict the distribution of the species at altitudes higher than 3300 m.     

Patch establishment and development of a clonal plant,Polygonum cuspidatum,on Mount Fuji

Microsatellite analysis was used to investigate the patch establishment and development of Polygonum cuspidatum Sieb. et Zucc, a clonal herbaceous plant that dominates the primary succession on the southeast slope of Mount Fuji. Genotypes of P. cuspidatum in 155 patches at the study site differed from each other. This indicates that P. cuspidatum patches are initially established by seed dispersed on the bare scoria field, and not by clonal rhizome extension. Genetic differentiation was estimated using the FST values between subpopulations at the study site. There was almost no genetic differentiation between subpopulations, indicating the presence of massive gene flow. The pollen fathers of seeds and maternal genets of current-year seedlings were inferred from the microsatellite allele composition by a simple exclusion method. The wide, random distribution of pollen fathers suggests that pollen dispersal occurs over a broad area. Maternal analysis showed a tendency for seed dispersal to be biased to the area nearby and down slope from the mother plants. Patch establishment under massive gene flow may result from such pollen and seed dispersal. To understand the process of patch development, aerial photographs taken from 1962 to 1999 were compared, and then genets in each of 36 patches were identified from the microsatellite genotypes of P. cuspidatum shoots. The comparison of aerial photographs showed that most of the patches enlarged each year and that some neighbouring patches combined during growth. Genet analysis demonstrated a high correlation between patch area and the area of the largest genet within it, and that new genets were recruited at the patch periphery. These findings indicate that both vegetative and sexual reproduction, i.e. rhizome extension and the establishment of new seedlings, contribute to the development of P. cuspidatum patches.     

HPLC法测定虎杖中白藜芦醇的含量

本文采用高铲液相色谱法测定虎杖白藜芦醇含量。测量条件：ODS－C18柱,流动相为甲醇－水（35：65）,检测波长：300nm。结果表明：白藜芦醇在0.4－2.0μg范围内具良好的线性关系,相关系数γ=0.9998,平均回收率为98.19％。     

Nitrification and nitrogen accumulation in the early stages of primary succession on Mt. Fuji

The relationship between nitrification potential and nitrogen accumulation was studied in an early successional sere on Mt. Fuji. Soil organic nitrogen accumulated with the invasion ofPolygonum cuspidatum and successively withMiscanthus oligostachyus and other species. Laboratory incubation experiments showed a higher nitrification potential at theM. oligostachyus state. The numbers of nitrifying bacteria increased with the progress of succession. No significant difference in nitrate reductase activity was found between pioneer and succeeding species. The soil solution at theM. oligostachyus stage contained a lower level of nitrate than rainwater, while that of the bare ground and theP. cuspidatum stage contained a higher nitrate level than rainwater. It was concluded that the high nitrate levels in the soil solution of the bare ground and theP. cuspidatum stage were due to lower nitrate-absorbing activity, leading to loss of nitrogen with precipitation, while the lower nitrate levels at theM. oligostachyus stage when higher nitrification activity occurred were due to higher nitrate-absorbing activity, preventing net loss of nitrogen from the ecosystem.     

Ecological studies on the timberline of Mt. Fuji

The distribution of the meadow above the timberline and the structure of the forest at and below the timberline were investigated on the southeast slope of Mt. Fuji. At the same time, soil profiles, water content and nutrients in the soil as related to change in the structure of the plant community were examined to obtain the data regarding soil development with the course of succession. In the course of change in structure of forest, the plant community was classified into three types:Salix/Alnus dwarf forest,Larix forest andAbies/Picea forest. The change in the soil profile, from immature to mature soil, was observed. At the timberline the water content increased rapidly from about 10% of bare land to about 25% of timberline. The nitrogen and carbon contents also increased at timberline as compared with bare land. Relationships between successional stage and soil development were clarified on the area from bare land to climax forest. The present state of the timberline at the investigated area is discussed with reference to the course of change in forest structure and soil development. It was concluded that the timberline of the investigated area is in the process of moving to a higher altitude. This conclusion was reasonable in view of the factor of air temperature.     

Ecological studies on the timberline of Mt. Fuji

To compare the nutrient economy of woody plants at timberline of Mt. Fuji, seasonal changes in nitrogen content in leaves were examined. There was remarkable difference in seasonal changes in leaf nitrogen content betweenAlnus maximowiczii and other deciduous trees at same habitat.A. maximowiczii scarcely withdrew the leaf nitrogen to woody part during the shedding period, while the other species withdrew about half of the leaf nitrogen to woody part.     

酶解法提高虎杖中白藜芦醇含量的研究

目的:提高虎杖中白藜芦醇的含量. 方法:采用酶解法使虎杖中白藜芦醇甙转化为白藜芦醇.对影响酶解的虎杖颗粒度、浸润用水量、酶解温度、时间4个因素进行考察,得出了最佳的酶解工艺. 结论:最佳酶解工艺是,虎杖粗碎至3 mm～10目、用3倍量的水浸润后、在(45±0.5) ℃下酶解2天.酶解后虎杖中白藜芦醇的含量提高了2.72倍.     

Ecological studies on the timberline of Mt. Fuji

An ecological study of dry matter production was made in a dwarf forest dominated byAlnus maximowiczii at the timberline of Mt. Fuji. Annual gross production was estimated by two methods, namely the summation method using stem analysis and total photosynthesis calculated from leaf area and photosynthetic rate per leaf area. Seasonal changes in relative light intensity and in leaf area were measured in a quadrat. Photosynthesis and respiration rates of samples were measured in temperature-regulated assimilation chambers. The phytomass was 2,989 g d.w.m^?2, and those of stems and branches, leaves, and roots were 1,672 g, 293 g, and 1,024 g respectively. The growing period of this plant was about four months and this plant expanded leaves quickly. The maximum gross photosynthetic rate was 21 mg CO₂dm^?2 h^?1 on September 1. Annual net production estimated by examining the annual rings was 922 g d.w.m^?2 year^?1 and annual respiration was 735 g. Annual gross production estimated from photosynthetic rates was 1,747 g d.w.m^?2 year^?1. The sum of annual net production by stem analysis and respiration agree closely with gross production estimated from photosynthetic rate. Gross production of this dwarf forest is comparable to the beech forest of the upper cool temperate zone owing to the high photosynthetic rate ofAlnus maximowiczii.     

大孔吸附树脂分离虎杖中白藜芦醇的研究

目的:采用大孔吸附树脂对虎杖粗提物中白藜芦醇进行初步富集、分离和纯化.方法:考察18种树脂对白藜芦醇的吸附量和解吸率,选择吸附量大、解吸率高的数种树脂进行吸附动力学研究,确定最佳的脱附工艺.结论:HPD-500树脂对白藜芦醇的吸附量可达58.67mg/g,解吸率为92.6%,经大孔吸附树脂的吸附与解吸,白藜芦醇的含量由粗提物中9.25%提高至39.5%.     

虎杖种质资源的分子标记研究

本文应用RAPD、ISSR和SRAP标记对26份虎杖种质资源遗传多样性进行检测.在22个引物中有17个引物(77.3%)扩增产物具多态性,多态性水平相对较高.22个引物共得到98条扩增DNA片段,其中90.8%具有多态性.每个多态性引物平均可扩增出5.24个多态性片段.聚类分析表明,利用BAPD、ISSR和SRAP技术相结合可将全部供试材料区分开,26份材料在Gs值0.54水平上全部聚为一类,以所有材料间的平均遗传相似遗传系数0.71为阈值,将其分为11类.虎杖种质资源在分子水平上确实存在较大遗传差异,RAPD、ISSR和SRAP标记可作为构建虎杖DNA指纹图谱的有效工具.     

MPLC测定虎杖中白藜芦醇含量

建立测定虎杖中白藜芦醇含量的反相中压高效液相色谱分析方法。实验采用SOURCE 5RPC ST 4.6/150预装拄,以乙腈:水(体积比30:70 V/V)溶液为流动相、流速l mL/min、检测波长308 nm。结果表明白藜芦醇对照品浓度在0.6~1.6 mg/mL时,浓度与峰面积呈良好的线形关系(R=0.9919);加样回收率为103.0~90.4%,RSD=7.21%。采用中压高效液相色谱法测定虎杖中白藜芦醇含量,操作方便,准确性和实用性好。     

Antioxidant activity of extract from Polygonum cuspidatum

Numerous diseases are induced by free radicals via lipid peroxidation, protein peroxidation and DNA damage. It has been known that a variety of plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum cuspidatum Sieb. et Zuce has antioxidant activity is unknown. In this study, dried roots of Polygonum cuspidatum were extracted by ethanol and the extract was lyophilized. Free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays were employed to study antioxidant activities. The results indicate that the IC50 value oí Polygonum cuspidatum extract is 110 microg/ml in free radical scavenging assays, 3.2 microg/ml in superoxide radical scavenging assays, and 8 microg/ml in lipid peroxidation assays, respectively. Furthermore, Polygonum cuspidatum extract has DNA protective effect in hydroxyl radical-induced DNA strand scission assays. The total phenolics and flavonoid content of extract is 641.1 +/- 42.6 mg/g and 62.3 +/- 6.0 mg/g. The results indicate that Polygonum cuspidatum extract clearly has antioxidant effects.     

Biotransformation of piceid in Polygonum cuspidatum to resveratrol by Aspergillus oryzae

Biotransformation of piceid in Polygonum cuspidatum to resveratrol by Aspergillus oryzae was investigated in this study. Resveratrol is widely used in medicine, food, and cosmetic because of its pharmacological properties. However, it has a much lower content in plants compared with its glucoside piceid, which has a much lower bioavailability. Traditionally, the aglycone is acquired by acid or enzymatic hydrolysis of its glucoside, but the violent condition and the acid pollution in hydrolytic reaction and the high cost of the enzyme limit their industrial development. In this paper, fermentation of P. cuspidatum by A. oryzae was successfully performed, during which, piceid was converted to resveratrol with the highest yield of trans-resveratrol 1.35%, 3.6 times higher than that obtained from raw herb by microwave-assisted extraction. Scale-up production was also performed and the yield of trans-resveratrol was 3.1 times higher after 24 h incubation. Therefore, biotransformation is a better method to increase the yield of resveratrol because of its high yield and mild conditions.     

虎杖提取物对弹性蛋白酶的抑制作用研究

本文主要研究了虎杖提取物对弹性蛋白酶的抑制作用。实验利用热水浸渍法提取虎杖得到粗提取物1(CE1),聚酰胺柱层析后得到粗提取物2(CE2),并进行一系列的定性及定量分析。分别用紫外分光光度法和荧光光谱法研究了提取物对弹性蛋白酶的抑制作用和荧光猝灭作用。实验结果表明CE1和CE2中均含有虎杖苷,含量分别为41.01%和69.57%。CE1、CE2和虎杖苷对弹性蛋白酶有一定的抑制作用,当浓度为2.0 mg/mL时,它们对弹性蛋白酶的抑制率分别为53.56%、61.27%和82.53%。CE1、CE2和虎杖苷对弹性蛋白酶均有明显的内源荧光猝灭作用,当浓度为0.1 mg/mL时,荧光猝灭率分别为70.38%、72.90%和75.99%。     

虎杖苯亚甲基丙酮合酶PcPKS2的表达纯化和晶体生长

植物类型Ⅲ聚酮合酶超家族(PKSs),又称查尔酮合酶(Chalcone synthase,CHS)超家族,催化合成多种植物次生代谢产物的分子骨架。苯亚甲基丙酮合酶(Benzalacetone synthase,BAS)催化4-香豆酰辅酶A与丙二酰辅酶A通过一步脱羧缩合反应生成苯亚甲基丙酮,是一系列具有重要生物学活性苯丁烷类化合物及其衍生物的前体化合物。前期工作从虎杖中分离出苯亚甲基丙酮合酶BAS(PcPKS2)和1个具有CHS和BAS活性的双功能酶(PcPKS1)。两者与超家族其他成员序列经比较,在包括门卫氨基酸Phe215和Phe265在内的重要氨基酸序列存在一定差异。已有蛋白晶体学研究结果表明,PKSs家族不同成员的功能多样性来自于酶催化位点的非常微小的构象变化。为了能够从结构上比较PcPKS2和Pc PKS1双功能酶活性差异可能产生的机制,以确定其高效BAS活性的分子机理,研究利用了大肠杆菌原核表达系统过量表达了C-端融合有His6标签的重组蛋白,经纯化得到了高纯度蛋白。经过对其晶体生长条件进行摸索和优化,得到了能用于X-射线衍射的单晶,为其结构解析、催化机理研究、了解虎杖聚酮类化合物生物合成机制和该类酶在基因工程中的应用提供了基础。     

凝胶柱层析分离虎杖中白藜芦醇的研究

本论文初步探讨了虎杖中白藜芦醇分离纯化的工艺条件,比较了不同溶剂、不同浓度、不同流速洗脱条件下白藜芦醇样品在LH-20凝胶层析柱上的分离效果,以及虎杖的乙醇提取液通过氯仿、乙酸乙酯萃取,凝胶柱层析分离后的成分变化,实验表明,当以甲醇为洗脱液,浓度为60%,流速为0.5 mL/min时,白藜芦醇样品的分离效果最好.采用中压液相色谱检测收集到的白藜芦醇纯度(以白藜芦醇峰面积占总峰面积计算)可达80.34%,回收率达86.16%.     

Nitrogen Use Efficiency in Growth of Polygonum cuspidatum Sieb. et Zucc

The growth of Polygonum cuspidatum in sand culture was analysedunder varying nutrient conditions. Nitrogen availability influencednitrogen uptake of plants through the uptake rate per unit rootweight rather than the amount of root. In turn, the differentamounts of nitrogen taken up affected plant growth through theireffects on the rate of leaf expansion. Net assimilation rate (NAR) increased with nitrogen contentper unit leaf area (C), but further increase in leaf nitrogencaused diminishing returns of NAR Optimal nitrogen content perunit leaf area (C_opt) to maximize dry-matter production of aleaf could be determined by drawing a tangent from the onginto a curvilinear relation between NAR and C. This optimal contentdivides a nitrogen-limiting range (C < C_opt) from a carbon-limitingone (C> C_opt) along the axis of nitrogen content. Under nitrogenlimitation, efficiency of nitrogen use in dry-matter productioncould increase if the plant had a larger carbon sink. This givesa qualitative explanation to reduced shoot-to-root ratio underlimited availability of nitrogen. Polygonum cuspidatum Sieb. et Zucc, Japanese knotweed, carbon sink, growth analysis, leaf nitrogen, net assimilation rate, nitrogen use efficiency     

虎杖不同部位白藜芦醇含量的分析

白藜芦醇(反-3,4,5-三羟基二苯乙烯,resveratrol)是一种活性多酚物质,也称芪三酚,1940年从毛叶藜芦(Veratrum puberulum Loes. f.)的根中最先得到.有研究认为,白藜芦醇及其苷是植物体在恶劣环境下或遇到病原侵害时自身分泌的一种抗毒素,因此有“植物杀菌素”之称[1].