恩施碎米荠愈伤组织诱导的研究

碎米荠(Cardamine hirsuta Linn)是十字花科碎米荠属,恩施碎米荠是在我国富硒地区湖北恩施发现的一种富集硒植物,具有很高的科学研究价值。研究以恩施碎米荠的幼叶为外植体,进行愈伤组织诱导的研究,结果表明:诱导愈伤组织的最佳培养基为:MS+TDZ0.3mg/L+2,4-D 0.6mg/L+30g蔗糖+6.5g琼脂,pH值5.8,诱导率高达63.3%。     

大叶碎米荠营养成分的研究

对大叶碎米荠的营养成分进行了详细的分析。结果表明,大叶碎米荠含有丰富的蛋白质、膳食纤维、氨基酸、矿物质和多种维生索,重金属含量远低于国家限量指标,是一种值得开发的绿色野生植物资源。     

安徽产碎米荠属二新变种

本文发表了安徽产碎米荠属二新变种,即黄山碎米荠Carda-mine chejiangensis T.Y.Chen et R.C.Fang var.huangshanensis D.C.Zhang var.nov.;圆齿白花碎米荠Cardamine leucantha(Tausch)O.E.Schulz var.crenata D.C.Zhang var.nov.。     

野生大叶碎米荠中的异硫氰酸盐成分分析

大叶碎米荠为十字花科碎米荠属多年生草本植物,作为药食同源蔬菜,具有通尿利便、止痛及治败血病等药效。异硫氰酸盐是存在于十字花科植物中的一种具有防癌抗癌作用的有机硫化合物。本研究用二氯甲烷从大叶碎米荠水解液中提取出硫代葡萄糖苷水解产物,经气相-质谱联用分析其组分,鉴定出2种异硫氰酸盐化合物,分别为异硫氰酸烯丙酯和异硫氰酸甲硫基烯丙酯,两者的含量分别为2.32 mg/kg、0.50 mg/kg。该研究为大叶碎米荠作为野菜资源开发利用提供了科学依据。     

碎米荠超氧化物歧化酶基因家族成员的鉴定和分析

为了解碎米荠(Cardamine hirsuta)的SOD基因特征,对SOD家族成员的基因结构、染色体定位、系统进化关系进行了分析,对顺式作用元件和蛋白结构进行了预测,并利用qRT-PCR技术检测各家族成员的组织表达模式。结果表明,碎米荠基因组中共有10个SOD基因(ChSODs),包括6个Cu/Zn-SOD、3个Fe-SOD和1个Mn-SOD。编码的ChSODs蛋白有57~ 324个氨基酸,分子量为6 419.41~34 659.01 kDa,理论等电点为4.92~9.60;系统进化树分析表明,碎米荠的ChSOD与拟南芥的AtSOD的同源性较高;ChSODs在根、茎、叶中均有表达,且在叶中高表达,其中CARHR085500和CARHR256690在叶和茎中表达量较高;顺式作用元件预测表明,碎米荠SOD响应多种非生物胁迫,其中对ABA和低温胁迫较为敏感; ChSODs蛋白质的二级和三级结构具有差异性。这表明碎米荠SOD基因在抗氧化过程中发挥重要作用。     

野生蔬菜壶瓶碎米荠异地栽培生物学特性及营养成分分析

壶瓶碎米荠(Cardamine hupingshanensis)在原产地为多年生草本,生长在低温、阴湿的环境中,分布地海拔800～1400m,湿度在80％以上,自然条件下,其繁殖方式为无性繁殖．壶瓶碎米荠在长沙异地栽培,10月到次年3月为营养生长,30～6月为生殖生长,7月植株逐渐枯死,表现为2年生．壶瓶碎米荠含有丰富的维生素C、维生素B1、烟酸和维生素B2,其中维生素B1是小白菜含量的9～17倍,矿质元素Ca、Mg、Mn、Zn等含量高,分别为小白菜含量的171％、294％、558％、297％,粗蛋白含量为13．0％,含氨基酸16种,其中7种为必需氨基酸．     

壶瓶碎米荠(Cardamine Hupingshanesis)胚和胚乳发育的研究

壶瓶碎米荠（Cardamine Hupingshanesis.）是十字花科中以营养体繁殖的多年生植物,在自然条件下,种子不易萌芽成苗。本文以碎米荠、油菜为对照材料对壶瓶碎米荠的胚胎发育进行了观察。壶瓶碎米荠胚发育经球形胚、心形胚、鱼雷形胚和子叶胚四个时期,属柳叶菜型。胚乳发育属核型发育类型,其胚胎发育过程和成熟胚结构与节状聚积和胚乳吸器,而壶瓶碎米荠和碎米荠无此类结构。通过胚胎发育观察证明,壶瓶碎米荠种胚结构完整,其种子不易萌发成苗可能与其特殊的生理原因有关。     

一株耐硒壶瓶碎米荠内生菌分离、鉴定及其体外硒代谢研究

【背景】壶瓶碎米荠对硒具有超积累能力,并主要以硒代胱氨酸的形式存在,与已有的硒超积累植物显著不同,其硒超积累机制不明。【目的】从硒超积累植物壶瓶碎米荠(Cardamine hupingshanensis)体内分离耐硒内生菌,并对其进行鉴定和体外硒代谢特征研究,为壶瓶碎米荠超积累硒的机制研究提供参考。【方法】从壶瓶碎米荠新鲜叶片中分离纯化耐硒内生菌株,对其进行生理生化特征及16S rRNA基因序列分析鉴定,并对其进行亚硒酸钠培养代谢。【结果】获得一株耐硒内生菌CSN-1,被鉴定为甲基营养型芽孢杆菌(Bacillus methylotrophicus),培养液中硒含量低(Se 1.5 mg/L)时其吸光度值较对照组高,硒含量高(Se 10 mg/L)时其吸光度值较对照组低;代谢后的上清液中硒主要以Se~(4+)存在,而菌体中硒主要是硒代胱氨酸(SeCys_2)。【结论】硒超积累植物壶瓶碎米荠叶片体内存在甲基营养型芽孢杆菌(Bacillus methylotrophicus)CSN-1,具有将亚硒酸钠转化为硒代胱氨酸的能力,低浓度的硒对该内生菌的生长具有一定的促进作用,而高浓度的硒则会抑制该内生菌的生长。     

《PLoS综合》：研究者发现新型超富硒植物

中国科学技术大学教授尹雪斌研究组在湖北恩施发现一种新型超富硒植物—壶瓶碎米荠,从而有望为硒缺乏者带来福音。相关研究在线发表于美国《公共科学图书馆·综合》。     

不同海拔下大叶碎米荠中激素含量差异的研究

目的:采用反相高效液相色谱法测定不同海拔大叶碎米荠中的ZT与IAA的含量。方法:ODS-5μm C-18柱(5μm,4.0 mm×250 mm),流动相A(甲醇)与B(0.6%冰醋酸),采用梯度洗脱,在前10 min,流动相B由100%降到50%,流速为1 mL/min,检测波长254 nm,柱温35℃。结果:其回收率92%以上,RSD<5%。不同海拔的激素含量存在显著差异,IAA在海拔2 100 m时含量最高,ZT在海拔600 m时含量最高,ZT/IAA值随着海拔上升而降低。     

Comparative study of rhizobacterial community structure of plant species in oil-contaminated soil

In this study, the identity and distribution of plants and the structure of their associated rhizobacterial communities were examined in an oil-contaminated site. The number of plant species that formed a community or were scattered was 24. The species living in soil highly contaminated with total petroleum hydrocarbon (TPH) (9,000-4,5000 mg/g-soil) were Cynodon dactylon, Persicaria lapathifolia, and Calystegia soldanella (a halophytic species). Among the 24 plant species, the following have been known to be effective for oil removal: C. dactylon, Digitaria sanguinalis, and Cyperus orthostachyus. Denaturing gradient gel electrophoresis (DGGE) profile analysis showed that the following pairs of plant species had highly similar (above 70%) rhizobacterial community structures: Artemisia princeps and Hemistepta lyrata; C. dactylon and P. lapathifolia; Carex kobomugi and Cardamine flexuosa; and Equisetum arvense and D. sanguinalis. The major groups of rhizobacteria were Betaproteobacteria, Gamma-proteobacteria, Chloroflexi, Actinobacteria, and unknown. Based on DGGE analysis, P. lapathifolia, found for the first time in this study growing in the presence of high TPH, may be a good species for phytoremediation of oil-contaminated soils and in particular, C. soldanella may be useful for soils with high TPH and salt concentrations. Overall, this study suggests that the plant roots, regardless of plant species, may have a similar influence on the bacterial community structure in oil-contaminated soil.     

A Study of Pollen Morphology of Some Aquatic Vascular Plants in Honghu Lake,Hubei

This paper deals with the pollen morphology of 22 species of the aquatic plants belonging to 18 genera and 13 families. 11 species of them are first time reported: Potarnogeton maackianus Benn; P. malaianus Miq., MyriophyUurn spicatum L., Zizania latifolia Turcz., Sagittaria sagittifolia L. var. longilaba Turcz., Polygonum hydropiper L., Ranunculus sceleratus L., Cardamine lyrata Bunge, Cyperus difforrnis L., Eleocharis pellucida Presl and Scirpus rnucronatus Diels. All pollen grains were observed under light microscope (LM) but 12 species among them were also examined under scanning electronic microscope(SEM). The environmental conditions and community structure of aquatic vegetation in the lake are briefly discussed.     

The contribution of common and rare species to species abundance patterns in alpine meadows: The effect of elevation gradients

Ecological niche modeling uses environmental variables associated with species distribution points to simulate species distribution and its importance in biodiversity conservation. This study aimed to quantify plant community composition and species abundance distribution (SAD) in alpine meadows at different elevations and to assess the contribution of rare and common species to SAD. We established a permanent study plot of 210 hm² in Gannan Tibetan Autonomous Prefecture, China, surveyed 315 sample squares (0.5 m × 0.5 m), and calculated the Hill numbers. The results showed that (1) a total of 72 species were surveyed at different altitudes, with Kobresia humilis and Kobresia macrantha as the main dominant species; (2) the SADs of overall and common species fit the ecological niche model (GSM (Geometric Sequence Model)), indicating that ecological niche differentiation is the main factor influencing SAD. The fitted model for rare species SAD varied with elevation, suggesting that various ecological processes influence rare species SAD. (3) Hill numbers showed a “single peak” pattern with increasing elevation. The number of rare species was higher than that of common species. Still, the distribution frequency of common species was significantly higher than rare species. The correlation between common-rare species sequences and cumulative species distribution was high. This indicates that common species dominate the species diversity pattern of the community, are the main contributors to the SAD pattern, and should be protected first. Rare species are also important carriers of community function and include much spatial information. Rare and common species work together in different ways to influence and maintain the species diversity patterns of alpine meadow plant communities.     

Selection on amino acid substitutions in Arabidopsis

Studies of nucleotide diversity have found an excess of low-frequency amino acid polymorphisms segregating in Arabidopsis thaliana, suggesting a predominance of weak purifying selection acting on amino acid polymorphism in this inbreeding species. Here, we investigate levels of diversity and divergence at synonymous and nonsynonymous sites in 6 circumpolar populations of the outbreeding Arabidopsis lyrata and compare these results with A. thaliana, to test for differences in mutation and selection parameters across genes, populations, and species. We find that A. lyrata shows an excess of low-frequency nonsynonymous polymorphisms both within populations and species wide, consistent with weak purifying selection similar to the patterns observed in A. thaliana. Furthermore, nonsynonymous polymorphisms tend to be more restricted in their population distribution in A. lyrata, consistent with purifying selection preventing their geographic spread. Highly expressed genes show a reduced ratio of amino acid to synonymous change for both polymorphism and fixed differences, suggesting a general pattern of stronger purifying selection on high-expression proteins.     

亚高寒草甸不同生境植物群落物种多度分布格局的拟合

物种多度分布是群落生态学研究的核心内容。通过对青藏高原东部亚高寒草甸3种不同生境草本植物群落的抽样调查,结合16个物种多度分布模型的两种曲线拟合优度检验得出如下结果：多种不同模型可以拟合同一生境的物种多度分布。相比于其他可拟合模型,几何级数模型在3种生境中两种拟合优度检验方法下的平均拟合效果是最好的,拟合优度值均在最优拟合优度值10左右波动。次优模型鉴于不同生境不同的检验方法表现不一。除了几何级数模型外,Sugihara分数模型在最小二乘法的拟合方法下,也可以拟合3种生境的物种多度分布。研究结果表明,仅用拟合优度检验区分产生不同物种分布格局的模型和机制是不可靠的,需要做进一步的检验性实验研究。     

亚热带峰丛洼地恢复演替植物群落的数量分类和排序——以广西马山弄拉峰丛洼地为例

采用双向指示种分析法(TWINSPAN)和除趋势对应分析(DCA)对弄拉峰丛洼地恢复演替植物群落进行数量分类和排序。TWINSPAN将20个样方分为10个组,根据植被分类的原则划分为10个群丛,论述了各群丛的群落学特征。20个样方的DCA排序结果反映了恢复演替群落与环境梯度的关系,表明影响群丛分布格局的主导生态因子为恢复时间、人为干扰及露石率。DCA排序将53个种分为4个种组,影响峰丛洼地恢复演替群落及其物种分布格局的主导生态因子为恢复时间、岩性和水分等。各物种在排序轴上的位置反映了种组成员的生态适应性及其在群落中的重要性和更新生态位。     

Does invasion involve alternation of germination requirements? A comparative study between native and introduced strains of an annual Brassicaceae, <Emphasis Type="Italic">Cardamine hirsuta</Emphasis>

Cardamine hirsuta is a European annual weed that has been naturalized in Japan. Although the species is a widespread weed in Europe, its introduction to the Japanese Islands occurred recently. We hypothesized that the introduction of Cardamine hirsuta required adaptation that has delayed its spread in Japan. The aim of this study is to determine whether there is a difference in temperature requirements for seed germination between Japanese and European strains of Cardamine hirsuta. We compared temperature requirements for seed germination, because it is known to be a critical determinant of phenology and thus is expected to be important in the success of introduction into different climates. Seeds of six and five strains from Japan and Europe, respectively, were used in seed germination experiments under five different temperature regimes. Japanese strains generally showed stronger initial seed dormancy and were characterized by suppressed germination in higher temperature regimes. European strains showed variable patterns of temperature-dependent seed germination. It turned out that these temperature-dependent dormancies are mediated by abscisic acid (ABA), because dormant seeds germinated under the presence of an inhibitor of ABA synthesis. Seed germination characteristics shared by Japanese strains presumably enhance long transport and autumn germination, while these characteristics are not necessarily common among European strains. The results are supportive for the idea that adaptation has altered germination characteristics of Cardamine hirsuta through the introduction process into Japan.     

Cross-species microsatellite markers for elucidating population genetic structure in Arabidopsis and Arabis (Brassicaeae)

Species closely related to model organisms present the opportunity to efficiently apply molecular and functional tools developed by a large research community to taxa with different ecological and evolutionary histories. We complied 42 microsatellite loci that amplify under common conditions in four closely related Arabidopsis: A. thaliana; A. halleri; A. lyrata ssp. lyrata; and A. lyrata ssp. petraea, as well as in one more distantly related crucifer; Arabis drummondii. Variation at these loci is amenable to a diversity of applications including population genetics, phylogeographical analyses, mapping of inter and intraspecific crosses, and recombination mapping. Our analysis of microsatellite variation illustrates significant differences in population genetic parameters among three Arabidopsis species. A population of A. thaliana, an inbreeding annual plant associated with disturbed habitats, was highly monomorphic (P = 8% percent polymorphic loci) and only 0.2% heterozygous for 648 locus-by-individual combinations. A population of the self-incompatible perennial herb, A. halleri, was more genetically variable (P = 71%) and had an excess of heterozygosity that may reflect a recent population bottleneck associated with human-mediated founder events. A population of the self-incompatible perennial herb, A. lyrata ssp. petraea, was even more genetically variable (P = 86%) and appeared to be at mutation-drift equilibrium. Population structure estimated from neutrally evolving loci provides an empirical expectation against which hypotheses of adaptive evolution at functional loci can be tested.     

Subdivision and haplotype structure in natural populations of Arabidopsis lyrata

High levels of inbreeding are expected to cause a strong reduction in levels of genetic variability, effective recombination rates and in adaptation compared with related outcrossing populations. We examined patterns of DNA polymorphism at five nuclear loci and one chloroplast locus within and between four populations of the outcrossing plant Arabidopsis lyrata, a close relative of the highly self-fertilizing model species A. thaliana. The observed patterns are compared with species-wide polymorphism at orthologous loci, as well as within- and between-population patterns at other studied loci in A. thaliana. In addition to evidence for much higher average within-population diversity, species-wide levels of silent polymorphism are generally higher in A. lyrata than in A. thaliana, unlike the results from a previous study of the ADH locus. However, polymorphism is also low in the North American A. lyrata subspecies lyrata compared with the European subspecies petraea, suggesting either a population bottleneck in North American populations or recent admixture involving diverged European populations. Differentiation between the two subspecies is strong, although there are few fixed differences, suggesting that their isolation is recent. Estimates of intralocus recombination rates and analysis of haplotype structure in European A. lyrata populations indicate lower recombination than predicted based on the variability together with physical recombination rates estimated from A. thaliana. This may be due to strong population subdivision, or to recent departures from demographic equilibrium such as a bottleneck or population admixture. Alternatively, there may be consistently lower recombination rates in the outcrossing species. In contrast, estimates of recombination rates from species-wide samples of A. thaliana are close to the values expected assuming a high rate of self-fertilization. Complex population histories in both A. thaliana and A. lyrata complicate theoretical predictions and empirical tests of the effects of inbreeding on polymorphism and molecular evolution.     

Horizontal mesoscale distribution of phytoplankton in the Tvärminne sea area,southern Finland

Horizontal distribution of phytoplankton was studied by sampling two grids, both having 16 sampling points. The distance between sampling points was 10 m. Phytoplankton species were enumerated by inverted microscopy and the observed distribution patterns were compared with a random distribution. Contagious distribution was common among the species studied. Both actively moving and passively drifting species showed significant contagiousness in their distribution. Actively moving and passively drifting species showed different distribution patterns. The effects of horizontal heterogeneity on phytoplankton sampling are discussed.