苗药果上叶立地环境调查研究

对苗药果上叶生长立地环境、气候状况、土壤理化特性及蕴藏量进行研究,研究结果表明:果上叶垂直分布在海拔400～1 800 m范围内,生长在陡坡石灰岩地带,所匍匐生长的岩石坡度基本在70°以上,在阴坡或半阴坡,喜温暖、湿润的环境,果上叶生长地土壤有机质含量高,残土比达0.42,土壤的排水性和保水性较好,呈弱酸性至中性;果上叶生长在盐肤木、青杠树、马尾松、荚蒾等乔木及部分缠绕的藤本植物下面,与蕨类和苔藓伴生;果上叶资源蕴藏量很少,处于濒危的程度。     

虾脊兰的栽培与利用(综述)

虾脊兰具有很高的观赏价值,是一类待开发的兰花资源。我国的野生资源十分丰富,本文参考前人的研究文献,结合本身工作,着重介绍虾脊兰的分布与研究概况,对虾脊兰引种栽培和繁殖技术做简要论述,并提出我国虾脊兰属植物今后利用及研究方向的建议。     

不同种源槜李的RAPD分析及主要农艺性状比较

运用RAPD标记方法对18个槜李(Prunus salicina Lindl. )种源及3个外类群的总基因组DNA进行了PCR扩增,在此基础上采用聚类分析方法对不同种源的遗传关系进行了分析,此外对18个槜李种源果实的主要农艺性状也进行了比较分析.RAPD分析结果表明,用从70条随机引物中筛选出的14条随机引物共扩增出71条带,其中多态性条带29条,多态性条带百分率达40.8%.聚类分析结果表明,在欧氏平方距离0.060处可将18个槜李种源和3个外类群分为7组,其中3个外类群分别单独成组,18个槜李种源可分为4组;姚学明和洪魏3这2个种源分别独立成组,洪魏2、王施、洪彭1、凤表1和凤表2等5个种源聚为一组,其他11个种源为一组.18个槜李种源果皮均为红色,其中深红色和暗红色各占50%;根据果实的成熟期可将18个槜李种源大致分为早熟型和晚熟型,成熟期分别为6月中下旬和7月上中旬;比较而言,早熟型的槜李种源具有单果质量较大、可溶性固形物含量较低、花期早3～4 d等特征.RAPD标记和农艺性状的综合分析结果显示,嘉兴地区的这些槜李种源在栽培过程中产生了突变和分化;姚学明这一种源与大多数槜李种源关系密切,并具有一定的优良特性,可能是1个优良种源,值得进行深入研究.     

枇杷茎尖二步玻璃化法超低温保存的研究

超低温保存是目前植物种质资源长期稳定保存最理想的方法,而近几年发展的玻璃化超低温保存法具有设备要求简单、材料处理步骤简便及效果和重演性好等特点,倍受人们的青睐。国内外用玻璃化法成功地保存许多果树的种质资源。在对枇杷（Eriobotrya japonica Lindl．）花粉超低温保存取得成功的基础上,作者进行了枇杷茎尖玻璃化超低温保存的研究,以期建立枇杷茎尖超低温保存体系,为长期稳定保存枇杷种质资源提供技术支持。     

Comparison of antitumor activities of different polysaccharide fractions from the stems of Dendrobium nobile Lindl

The antitumor activities of extracted polysaccharide fractions from the stems of Dendrobium nobile Lindl were investigated. Polysaccharides were sequentially extracted from the stems of D. nobile to obtain three fractions, i.e. water extract fraction (DNP-W), 5% NaOH extract fraction (DNP-OH) and 5% HCl extract fraction (DNP-H). Further the DNP-W was isolated to give six sub-fractions (DNP-W1, DNP-W2, DNP-W3, DNP-W4, DNP-W5 and DNP-W6) by anion-exchange chromatography. The monosaccharide profile, protein content, uronic acid content, total carbohydrate content, viscosity and molecular weight of nine polysaccharide fractions were analyzed. Both the in vivo and in vitro antitumor activities of nine polysaccharide fractions were evaluated and compared. Results indicated that DNP-W1 and DNP-W3 exhibited high antitumor activities against Sarcoma 180 in vivo and HL-60 in vitro. The results suggested that DNP-W1 and DNP-W3 could be considered as an effective natural antitumor source.     

Differences in Cold Inactivation of Phosphoenolpyruvate Carboxylase among C4 Species: The Effect of pH and of Enzyme Concentration

Among various C4 plants we found a wide range in the level of inactivation of phosphoenolpyruvate carboxylase (PEPC) at low temperature (0 °C). The activity of the 2-fold diluted enzyme in crude leaf extracts after 60 min incubation (compared to zero time incubation) at pH 7.5, remained above 87 % at low temperatures for the species Setaria verticillata, Portulaca oleracea, and Saccharum officinarum, and between 11 and 17 % in the species Cynodon dactylon and Atriplex halimus. The enzyme exhibited intermediate levels of inactivation (42 to 58 %) for the species Amaranthus sp., Zea mays, Salsola kali, and Digitaria sanguinalis. The enzyme activity for S. verticillata was unaffected between pH 5.7 and 8.4 during incubation at room and low temperatures. Under similar conditions, the activity of the enzyme from C. dactylon was stable between pH 5.7 and 7.0 and decreased at pH above 7.0, but for Z. mays it was enhanced between pH 5.7 and 6.8 and decreased at pH above 7.0.     

A novel terrestrial halophilic environment: The phylloplane of Atriplex halimus, a salt-excreting plant

Abstract This paper describes the microbial ecosystem found on the leaves of Atriplex halimus , a salt-excreting plant in the central Negev highlands of Israel. Because of the regular nightly occurence of dew at this location, these leaves undergo a diurnal wetting so that phylloplane microorganisms experience large fluctuations in salinity and water activity, as well as tolerate repeated desiccation. During the dry season, in the late spring and summer, a significant amount of salts and organic material coats the leaf surface. During dew events the salt concentration at the leaf surface was calculated to be > 0.4 M. Direct counts of the respiring bacteria on the leaf surface ranged from 1.06×10⁴ to 5.06×10⁵ per cm². Using a variety of media it was shown that there was limited bacterial diversity which could be cultured, with greater than 90% of the isolates being orange colored Gram-negative rods. Viable counts ranged from 0.32 to 2.32×10⁴ bacteria per cm² of A. halimus leaf surface. No bacteria capable of nucleating ice were recovered in these studies. The dominant orange pigmented bacterium, identified as a halotolerant Pseudomonas sp., grew optimally at 30°C and at 5% NaCl and was capable of growth in media containing up to 20% NaCl. This bacterium could grow on a variety of organic compounds, including some associated with plant materials. The leaf bacteria were desiccation-tolerant when on the leaf surface or when directly washed off the leaves, but much less so when in isolatd culture. A major component of the tolerance to desiccation is probably related to the compounds on the leaf surface.     

中国滨藜属种子形态及其分类学意义

本文对中国滨藜属(Atriplex L.)13种植物的种子形态进行了观察并探讨其在分类学中的意义. 在种子外部形态观察基础上明确了胚根位置类型的划分标准, 认为滨藜属胚根位置仅有胚根上位和胚根侧位两种类型;利用扫描电镜首次观察报道了该属种皮微形态特征。研究结果表明, 种子形态及种皮微形态特征对属内类群划分具有较大的分类学意义。     

Loss of genetic variation in geographically marginal populations of Atriplex tatarica (Chenopodiaceae)

BACKGROUND AND AIMS: Genetic variability was estimated for Atriplex tatarica from 25 populations in the Czech Republic. Since its north-western range margin is in central Europe, a relationship between marginality and low within-population genetic diversity was tested in accordance with the Central-Marginal Model. METHODS: Population genetic diversity was expressed by assessing patterns of variation at 13 putatively neutral allozyme loci (comprising 30 putative alleles) within and between 25 natural populations of A. tatarica along a north-west-south-east transect in the Czech Republic. KEY RESULTS: Atriplex tatarica is a species of human-made habitats with a mixed mating system and wide geographic distribution. Overall, A. tatarica displayed moderate levels of genetic diversity in comparison with other herbaceous plants. The percentage of loci that were polymorphic was 47.1%, with average values of 1.55, 0.151 and 0.155 for the average number of alleles per polymorphic locus (A), observed heterozygosity (Ho) and expected heterozygosity (He), respectively. There was only weak evidence of inbreeding within populations (FIS=0.031) and significant population differentiation (FST=0.214). Analysis of the data provides no evidence for isolation-by-distance for the whole study area. However, Mantel tests were highly significant for the marginal Bohemian region and non-significant for the central Moravian region. While northern populations of A. tatarica showed significantly lower allelic richness (A=1.462) than populations from the southern part of the study area (A=1.615), they did not differ in observed heterozygosity (Ho), gene diversity (HS), inbreeding within populations (FIS) or population differentiation (FST), despite generally lower values of particular genetic measurements in the marginal region. CONCLUSIONS: Genetic diversity, with the exception of allelic richness, was not significantly lower at the margins of the species' range. This, therefore, provides only weak support for the predictions of the Central-Marginal Model.