真菌B-39与虎杖悬浮细胞的共培养

初步探讨了虎杖来源真菌B-39与虎杖悬浮细胞之间的共培养关系及其白藜芦醇的积累特征。通过肉眼和光学显微镜观察真菌B-39与虎杖悬浮细胞的形态结构及生长情况,并用HPLC检测其白藜芦醇的积累特征,结果表明,两者均能在共培养体系中正常生长,且生长量可达4.908g,但白藜芦醇的含量下降了50μg/mL,而真菌接种量的大小可与虎杖悬浮细胞共培养建立一种动态平衡体系,由此推测真菌B-39与虎杖悬浮细胞可能为共生状态。     

Antioxidant flavonoids from leaves of Polygonum hydropiper L

Ten flavonoid compounds were isolated from the dried leaves of Polygonum hydropiper L. (Laksa leaves), and identified as 3-O-alpha-L-rhamnopyranosyloxy-3',4',5,7-tetrahydroxyflavone; 3-O-beta-D-glucopyranosyloxy-4',5,7-trihydroxyflavone; 6-hydroxyapigenin; 6"-O-(3,4,5-trihydroxybenzoyl) 3-O-beta-D-glucopyranosyloxy-3', 4', 5, 7-tetrahydroxyflavone; scutillarein; 6-hydroxyluteolin; 3',4',5,6,7-pentahydroxyflavone; 6-hydroxyluteolin-7-O-beta-D-glucopyranoside; quercetin 3-O-beta-D-glucuronide; 2"-O-(3,4,5-trihydroxybenzoyl) quercitrin; quercetin. Evaluation of the antioxidative activity, conducted in vitro, by using electron spin resonance (ESR) and ultraviolet visible (UV-vis) spectrophotometric assays, showed that these isolated flavonoids possess strong antioxidative capabilities. Measurement of the Trolox equivalent antioxidant capacity (TEAC) values, against ABTS (2,2'-azinobis(3-ethyl-benzo-thiazoline-6-sulphonic acid) radicals and phenyl-tert-butyl nitrone (PBN) azo initiator (AI) also showed strong anti-oxidative activity. The most powerful of the antioxidants was 2"-O-(3,4,5-trihydroxybenzoyl) quercitrin (galloyl quercitrin). A combination of two flavonoid compounds was tested for synergistic anti-oxidative capacity, but no significant improvement was observed.     

A Test of Two Annual Cover Crops for Controlling Phalaris arundinacea Invasion in Restored Sedge Meadow Wetlands

Abstract Rapid establishment by aggressive plants such as Phalaris arundinacea (reed canarygrass) often interferes with sedge meadow establishment in restored prairie pothole wetlands in the mid‐continental United States. Introducing a cover crop during community establishment might suppress P. arundinacea invasion in restored prairie potholes by reducing resource availability. We evaluated two potential cover crops, Echinochloa crusgalli (barnyardgrass) and Polygonum lapathifolium (nodding smartweed), for suppressing P. arundinacea invasion in an experimental wetland using replacement series competition experiments. Further, we assessed the effects of E. crusgalli and P. lapathifolium on sedge meadow establishment by sowing Carex hystericina, a common wetland sedge, as a third species at a constant density in the replacement experiments. Echinochloa crusgalli, compared with no cover crop, reduced P. arundinacea biomass by more than 1,000 g/m² (65%) after two growing seasons. Polygonum lapathifolium did not affect P. arundinacea biomass. Dense E. crusgalli canopies in the first year and thick E. crusgalli thatch in the second year substantially reduced light availability for P. arundinacea establishment. Echinochloa crusgalli also reduced C. hystericina biomass by more than 1,800 g/m² (99%) after two growing seasons. Carex hystericina biomass was similar in plots sown with E. crusgalli to P. arundinacea monocultures. Neither E. crusgalli nor P. lapathifolium is likely to improve sedge meadow restoration success. These trends were not sensitive to initial sowing density or elevation above water level. Without methods to suppress P. arundinacea invasions, sedge meadow restorations may often fail. Thorough site preparation to remove P. arundinacea propagule sources before restoration is essential.     

红蓼中木脂素成分的研究

从红蓼（ＰｏｌｙｇｏｎｕｍｏｒｉｅｎｔａｌｅＬ．）中分得３个木脂素类化合物,经光谱分析和化学方法鉴定为牛蒡子甙（１）、拉帕酚Ｂ（２）和红蓼脂素（３）。其中化合物３为新化合物,１和２为首次从该植物中分离得到。     

Improved indirubin production in a two-phase suspension culture of Polygonum tinctorium using dimethylpolysiloxane

Dimethylpolysiloxane (DMPS), used as a second phase in a suspension culture of Polygonum tinctorium, increased indirubin production by up to 259% and 16% in shake flask and air-lift bioreactors, respectively. In the shake flask culture, indirubin production increased by up to 248 mg/l using 90% v/v DMPS (volume of DMPS/volume of medium). In an air-lift bioreactor culture grown at a perfusion rate of 0.05 day–1 the indirubin concentration reached a maximum of 130 mg/l using 50% (v/v) DMPS. For the same DMPS content, the lower indirubin production in an air-lift bioreactor was probably due to the mass transfer limitation of indirubin between the two phases. © Rapid Science Ltd. 1998     

何首乌胚和胚乳的发育

何首乌为直生胚珠,双珠被。胚发育属于柳叶菜型。心形胚柄最为发达,鱼雷形胚期胚柄奶化。早期胚胎发育营养的主要来源可能是合了中积累的淀粉和胚柄吸收来的营养。成熟胚中积累了大量的蛋白质和淀粉粒。胚乳发育属核型。从球形胚期起,胚乳细胞化过程由珠孔端向合点端逐渐推进。初始垂周壁源于姊妹核间的细胞反或非姊妹核间由次生成膜生的细胞板。初始平周壁源于有丝分裂所产生的细胞板。心形胚期,除合点端保持游离核胚乳吸器外,     

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.     

The dual role of temperature in the regulation of the seasonal changes in dormancy and germination of seeds of Polygonum persicaria L.

Summary The role of temperature in the regulation of seasonal changes in dormancy and germination was studied in seeds of Polygonum persicaria. Seeds were buried in the field and under controlled conditions. Portions of seeds were exhumed at regular intervals and germination was tested over a range of conditions. Seeds of P. persicaria exhibited a seasonal dormancy pattern that clearly showed the typical features of summer annuals, i.e. dormancy was relieved at low winter temperatures, the germination peak occurred in spring and dormancy was re-induced in summer. The expression of the dormancy pattern was influenced by the temperature at which germination was tested. At 30°C exhumed seeds germinated over a much longer period of the year than at 20° or 10°C. Nitrate added during the germination test occasionally stimulated germination. The seasonal changes in dormancy of buried seeds were regulated by the field temperature. Soil moisture and nitrate content did not influence the changes in dormancy. The fact that, on the one hand, field temperature determined the changes in dormancy and, on the other hand, germination itself was influenced by temperature, was used to describe the seasonal germination pattern of P. persicaria with a model. Germination of exhumed seeds in Petri dishes at field temperature was accurately described with this model. Germination in the field was restricted to the period where the range of temperatures over which germination could proceed (computed with the model) and field temperature overlapped.