The effect of gap dynamics on the size and spatial structure of Solidago sempervirens on primary coastal dunes

Abstract. The role of gap dynamics in shaping the spatial and size distributions of the gap specialist Solidago sempervirens (seaside goldenrod) were examined on the primary dune grassland (Ammophila breviligulata, American beachgrass) of an Atlantic barrier island. Results suggest that coastal dune blowouts are patchy disturbances that allow S. sempervirens to temporarily establish and disperse seed. Natural measurements and clipping experiments demonstrated that A. breviligulata competitively dominated S. sempervirens in undisturbed grasslands. Coastal dune blow-outs reversed this dominance by temporarily burying A. breviligulata and increasing densities and above-ground biomass of S. sempervirens. Examination of size/density distributions of S. sempervirens suggested that blow-outs were seed sources but not regeneration sites. Regeneration was found primarily in neighboring transition and undisturbed grassland areas. Comparison of lateral growth by A. breviligulata on blow-out margins suggested that disturbances were closed by lateral encroachment from gap edges. After blow-out recovery, greater densities and skewed size distributions of S. sempervirens could still be detected for a number of years after blow-out recovery.     

野葛毛状根离体培养与异黄酮生产

用发根农杆菌（Agrobacterium rhizogenes）R1601菌株感染野葛（Pueraria lobata(Willd.)Ohwi）叶片外植体后获得的毛状根,经连续4次继代培养,鲜重增加到最初的6.2倍。PH为5.5的1/2SH液体培养基较适合野葛毛状根的生长。与自然根相比,毛状根在无激素的1/2SH液体培养基中离体培养20d后,鲜重增加22.6倍,释放入培养液中的异黄酮量增加10.6倍。毛状根生产异黄酮的量略高于自然根,且根中含量明显高于愈伤组织及茎中异黄酮的含量。培养液体积影响毛状根的离体生长及异黄酮的释放。     

Myrothecium verrucaria isolates and formulations as bioherbicide agents for kudzu

The fungus Myrothecium verrucaria (MV) has previously been shown to have potential as a bioherbicide for kudzu (Pueraria lobata) control. It has also been shown that MV wild-type (MV-wt) often forms sectors, when grown on various nutrient media. Experiments compared MV-wt and MV sector efficacy when grown on agar or on rice grains. In greenhouse evaluations of sectors, applied as foliar sprays in water or in other formulations (corn oil, surfactant, and corn oil plus surfactant) for efficacy against kudzu seedlings, some sectors possessed bioherbicidal activity equal that of MV-wt, but others exhibited lower activity. Without a dew period, aqueous formulations of MV-wt, a yellow sector, and a white sector provided zero control, but all three isolates were active without a dew period when formulated in corn oil, Silwet L-77 surfactant, and in surfactant plus corn oil. Generally, the yellow sector was less effective than the other two isolates in any formulations, and the MV-wt and white sector provided approximately 100% mortality of the test plants. Dew (10 h) increased weed control to 100, 33, and 65%, respectively, for MV-wt, the yellow sector and the white sector. All isolates provided nearly 100% control in the oil and surfactant formulations with a dew period compared to treatments receiving no dew. Soil incorporation studies were also performed to compare MV-wt efficacy of preparations grown on agar versus growth on rice grains. Higher efficacies (1.75-3.3-fold increase) were obtained from rice grain preparations compared to preparations grown on agar, when preparations were incorporated at several rates into soil prior to planting. Cell-free extracts of the MV-rice cultures were also phytotoxic to kudzu seedlings up to the eight- to 10-leaf growth stage. Thus, formulation, growth media, and the application method are important determinants in the efficacy of MV and MV sectors on kudzu seedlings.     

野葛的组织培养和植株再生

野葛〔Ｐｕｅｒａｒｉａｌｏｂａｔａ（Ｗｉｌｄ．）Ｏｈｗｉ〕为豆科多年生缠绕藤本植物,分布遍及全国,主产南方［１］,可药食两用,其块根肥厚,富含淀粉、蛋白质、钙、磷、铁及脂肪酸等,还含有多种异黄酮类化合物,对治疗心绞痛、高血压、冠心病,抑制肿瘤等效果显...     

Spatial dynamics of regeneration in a conifer/broad‐leaved forest in northern Japan

Abstract. This study deals with stand dynamics over a 6‐yr period in a conifer/broad‐leaved mixed forest in Hokkaido, northern Japan. The annual rates of gap formation and recovery were 81.3 m²/ha and 66.7 m²/ha, respectively and turnover time of the canopy was 125 yr. The recruitment processes of the component species in this cool‐temperate forest were governed by different canopy types: gap, canopy edge and closed canopy. Magnolia obovata regenerated in canopy edges, and Acer mono and Prunus ssiori regenerated in canopy edges and gaps. The results suggested that the mosaic structure made up of closed canopy, canopy edge and gap was related to various regeneration niches. Abies sachalinensis had high mortality rates, initiating gap expansion. The transition probabilities from closed canopy or canopy edge to gap for deciduous broad‐leaved trees were lower than for A. sachalinensis, which implies that the difference in degeneration patterns of conifer and broad‐leaved canopies contributes to the heterogeneity of spatial structure in the mixed forests. Spatial dynamics were determined by a combination of gap expansion by A. sachalinensis (neighbour‐dependent disturbance) and gap formation by deciduous broad‐leaved trees (random disturbance).     

DMSO、Tween-20和Triton X-100对野葛悬浮细胞异黄酮生产的影响

二甲基亚砜(DMSO)、Tween-20和Triton X-100可以增大悬浮培养细胞的细胞膜和液泡膜的透性,促进细胞内次生代谢物的释放,从而影响这些次生代谢产物的产量。为了提高野葛悬浮细胞中异黄酮类化合物的产量,以1％、3％和5％的DMSO、Tween-20和Triton X-100分别处理野葛叶悬浮细胞,结果显示,Tween-20和Triton X-100皆明显促进细胞生物量和葛根素和异黄酮化合物的释放。5％的Triton X-100处理3d,促进细胞产生总异黄酮化合物,增产率达40．6％。     

中国白粉菌属的分类研究Ⅳ.十字花科上的一个新种

本文描述了采自北京香山的细子薄菜 Rorippa cantoniensis(Lour.)Ohwi(十字花科)上的一种新白粉菌 Erysiphe rorippae Chen & Zheng sp.DOV.蔊菜属是白粉菌属的寄主新记录。在附属丝形态上,本新种因附属丝往往在顶部略膨大呈棍棒形而与唇形科上的华阴白粉菌 Erysiphe huayinensis Zheng & Chen 颇为近似,但因子囊壳直径较大,子囊孢子数目较少、体积较大且在两端钝尖而与该种很易区分。与十字花科上的另外两个已知种,即十字花科白粉菌 Erysiphe cruciferarura(Opiz)Junell 和南芥白粉菌 Erysiphe arabidisZheng & Chen 相比则无论在什么方面都没有共同之处。这三个种可检索如下:     

山西省野葛种质资源分布与植物学性状研究

了解山西省野葛种质资源的分布状况、群落组成以及植物学特性,为晋产野葛资源的挖掘、保护和可持续利用提供参考依据。对山西境内12个产地野葛的植物学性状及生长环境进行实地调查。结果表明,山西省野葛种质资源主要分布于晋南的中条山区域和晋北的太行山区域。从水平分布看,山西野葛主要分布于34°47'04.77″~39°31'05.23″N,110°30'17.80″~114°33'18.24″E;垂直分布介于730~1240 m之间,以海拔730~950 m最为常见。山西野葛生长的区域年均降水量介于400~800 mm之间,年均温度为6.8~14℃。山西野葛的群落组成较为单一,大部分伴随其生长的是较矮的灌木丛,少部分伴随有杨树、刺槐等。根据生态环境的不同,可将山西野葛大致分为疏林灌木型、河道草地型和砂质土壤型3种类型。     

太白山野葛根中异黄酮和葛根素含量随季节的变化

为了考察太白山野葛根中异黄酮及葛根素含量随季节的变化。采集一年12个月份的野葛根,采用紫外分光光度法测定其中异黄酮含量;以7高效薄层色谱扫描法测定野葛根中游离葛根素及总葛根素含量。结果表明：三月份异黄酮含量最高,为18.53%;四月份游离葛根素及总葛根素含量最高,分别为7.45%和8.93%。对不同季节太白山野葛根中异黄酮、游离葛根素及总葛根素进行定量分析,为这一野生资源的合理采收和开发利用提供了实验依据。     

中国莎草科一新记录种——菊芳薹草

报道了中国莎草科(Cyperaceae)薹草属一新记录种——菊芳薹草(Carex trongii K.K.Nguyen)。该种分布于我国广西与越南交界地区的石灰岩地区。菊芳薹草与宽叶薹草组(Carex sect.Siderostictae Ohwi)的种类在形态上近似,但以秆中生和果囊密被糙毛而易于区别。提供了菊芳薹草的形态描述和线条图。