Development of tools for assessing conservation categories of siluroid fishes of fresh water and brackish water wetlands of South West Bengal,India

Twenty-five species of fishes belonging to 18 genera, 7 families under the order siluriformes have been recorded from different freshwater and brackish water wetlands of South West Bengal, India. Fishery potential of 17 commercially important siluroid fishes were noted especially from market surveys as well as from information collected from local fishermen communities. Following the IUCN guidelines, and also through Participatory Rural Appraisal (P.R.A.) methods, an attempt has been made to assess the conservation status of such fishes, many of which are thought to be threatened. Trend analysis, Fish Magnitude Value and Rank based Quotient revealed the threatened status of 17 siluroid fishes.     

A specific PCR assay for the diagnosis of Clonorchis sinensis infection in humans, cats and fishes

Clonorchiasis caused by Clonorchis sinensis is a fish-borne parasitic disease which is endemic in a number of countries. Using the sequences of the internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA (rDNA) of C. sinensis as genetic markers, a pair of C. sinensis-specific primers was designed and used to establish a specific PCR assay for the diagnosis of C. sinensis infection in humans, cats and fish. This approach allowed the specific identification of C. sinensis after optimizing amplification conditions, with no amplicons being amplified from related heterogeneous DNA samples, and sequencing of amplicons confirmed the identity of the sequences amplified. The detection limit of this assay was 1.03 pg of adult C. sinensis, 1.1 metacercariae per gram of fish filet, and a single egg in human and cat feces. The PCR assay should provide a useful tool for the diagnosis and molecular epidemiological investigation of clonorchiasis in humans and animals.     

Application of fuzzy theory and PROMETHEE technique to evaluate suitable ecotechnology method: A case study in Shihmen Reservoir Watershed, Taiwan

With the increase in industrial development and improper land uses, Taiwan has faced the extinction crisis and is seeing the signs of nature, revenge in the forms of frequent landslides, floods, and debris flows in recent years. The government has strongly promoted the concept of ecotechnology in the hope of maintaining the ecosystem and its integrity. However, the application of ecotechnology is still in its infancy, so there is currently no objective evaluation standard to assess its effectiveness. Deficiencies in the scientific approach to quantify the results are due to current disputes and bottlenecks in its implementation. In order to seek reasonable and feasible methods to overcome the deficiencies in the implementation of the scientific approach, this study collected domestic and international ecological evaluation models to develop innovative processes that utilize ecological, safety, and cost indices. First, the commonly used ecotechnology methods for river embankment were acquired from the governmental departments. Second, the ecological, safety and cost indices for the acquired ecotechnology methods and construction sites were analyzed and quantified using fuzzy theory. Third, indices of ecotechnology methods were linked with those of construction sites for the PROMETHEE technique evaluation for suitable ecotechnology method selection. A practical construction case located in Shihmen reservoir watershed was chosen for evaluation and verification. The results show that the developed model can provide useful information for decision making while performing ecotechnology engineering.     

湖北后河国家级自然保护区生物多样性及其保护对策 II.生物多样性保护现状、威胁及其对策

湖北后河自然保护区拥有丰富的生物多样性,为中国生物多样性三大关键地区之一的川东-湘鄂西关键地区的重要组成部分。但所处的贫困山区少数民族县长期以来以森工产业为其县域经济的主要支柱,长期的木材采伐和狩猎习俗曾对该保护区的生物多样性带来了严重破坏。自然保护区的建立使其生物多样性逐渐得到了有效保护,特别是升为国家级自然保护区后,生物多样性保护进入了一个新阶段。但该保护区的生物多样性依然面临多种威胁,保护区自身科学研究力量的薄弱和保护区面积相对较小,限制着该区域生物多样性的进一步研究和保护。进一步扩充保护区面积、引进科研力量并提升自身人员科研素质、协调并增强区内外社区共管是该区生物多样性得到进一步保护和恢复的当务之急。     

Assessment of heavy metal contamination and Hg-resistant bacteria in surface water from different regions of Delhi,India

The present study aims to monitor the surface water quality of different regions in Delhi (India). With many physical and chemical properties, all samples had a high load of pollution in which Najafgarh drain (Nd) exhibited maximum and laboratory tap water (Ltw) minimum contamination. Water samples contained notable amounts of heavy metals including Cr, Cd, As, Cu, Pb and Hg. A total of 88 Hg-resistant bacteria were isolated from all the regions except Ltw. Among all the samples, the density of Hg-resistant bacteria was highest in sample of Nd and their morphotype heterogeneity was highest in sample collected from river Yamuna nearby Kashmiri gate (Kg). Different strains showed different patterns of resistance to different heavy metals and antibiotics. Multiple antibiotic resistance (MAR) indices were high in two samples, the highest reported in a sample taken from river Yamuna nearby Majnu ka tila (Mkt) (0.34). The 12.5% and 24.45% isolates showed β- and α-hemolytic natures, respectively that might be of pathogenic concern. In this account, high concentrations of heavy metals and their resistant bacteria in surface water have severely damaged the quality of water and their resources and produced high risk to the associated life forms.     

Environmental and Human Health Risk Assessment of Benzo(a)pyrene Levels in Agricultural Soils from the National Capital Region,Delhi, India

ABSTRACT

Exposure to benzo(a)pyrene (B(a)P) for health risk was studied in soils from the Delhi region, India. The mean and median concentrations of benzo(a)pyrene were 0.031 and 0.029 (±0.002) mg/kg, respectively. The lifetime average daily dose (LADD) for adults and children was 1.7 × 10^?8 mg kg^?1 d^?1 and 7.5 × 10^?8 mg kg^?1 d^?1, respectively, with incremental life time cancer risk (ILCR) of 1.2 × 10^?7 and 5.5 × 10^?7, respectively. The Index of Additive Cancer Risk (IACR) was 0.084. Our screening-level risk assessment shows that the observed ILCR and IACR values are much lower than the guideline values of 10^?6 ? 10^?4 (ILCR) and <1 (IACR), respectively, and therefore the measured B(a)P levels in soil may not portend environmental and human health risks.     

Dual location of MAR-binding, filament-like protein 1 in Arabidopsis, tobacco, and tomato

Matrix attachment region-binding filament-like protein 1 (MFP1) is a plant-specific long coiled-coil protein that binds double-stranded DNA. While originally identified as a component of the tobacco nuclear matrix, it was subsequently shown that the majority of MFP1 resides in mature chloroplast where it is located at the stroma side of the thylakoids and is able to bind to nucleoids. On the other hand, a 90 kDa MFP1-like protein from onion has been convincingly shown to be an intrinsic component of the onion meristematic nuclear matrix. Here, we have expanded the analysis of the subcellular location of MFP1 by using high-resolution confocal immunofluorescence microscopy and immunogold electron microscopy. Two different antisera raised against MFP1 from two species were used on isolated nuclei and chloroplasts from tomato, tobacco, and Arabidopsis. Our data show that both antibodies detect a signal in both compartments in all three species. An Arabidopsis MFP1 T-DNA insertional mutation abolishes both nuclear and chloroplast signals, indicating that the nuclear and plastidic antigens are derived from the same gene. We therefore suggest that MFP1 is a protein with a dual location, in both nuclei and chloroplasts, consistent with prior findings in onion and the dicot species investigated here.     

Dietary omega-6 fatty acid lowering increases bioavailability of omega-3 polyunsaturated fatty acids in human plasma lipid pools

BackgroundDietary linoleic acid (LA, 18:2n-6) lowering in rats reduces n-6 polyunsaturated fatty acid (PUFA) plasma concentrations and increases n-3 PUFA (eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) concentrations.ObjectiveTo evaluate the extent to which 12 weeks of dietary n-6 PUFA lowering, with or without increased dietary n-3 PUFAs, alters unesterified and esterified plasma n-6 and n-3 PUFA concentrations in subjects with chronic headache.DesignSecondary analysis of a randomized trial. Subjects with chronic headache were randomized for 12 weeks to (1) average n-3, low n-6 (L6) diet; or (2) high n-3, low n-6 LA (H3–L6) diet. Esterified and unesterified plasma fatty acids were quantified at baseline (0 weeks) and after 12 weeks on a diet.ResultsCompared to baseline, the L6 diet reduced esterified plasma LA and increased esterified n-3 PUFA concentrations (nmol/ml), but did not significantly change plasma arachidonic acid (AA, 20:4n-6) concentration. In addition, unesterified EPA concentration was increased significantly among unesterified fatty acids. The H3–L6 diet decreased esterified LA and AA concentrations, and produced more marked increases in esterified and unesterified n-3 PUFA concentrations.ConclusionDietary n-6 PUFA lowering for 12 weeks significantly reduces LA and increases n-3 PUFA concentrations in plasma, without altering plasma AA concentration. A concurrent increase in dietary n-3 PUFAs for 12 weeks further increases n-3 PUFA plasma concentrations and reduces AA.     

Microfacies controls on weathering of carbonate building stones: Devonian (northern Sauerland,Germany)

Summary The Beisinghausen Limestone (Upper Givetian to Frasnian) in the Eslohe-Reiste area (northern Sauerland), used in the past as building stone, corresponds to proximal carbonate turbidites which have been derived from the Attendom-Elspe ‘reef’ complex. The particles of this allodapic limestone originated in different parts of the carbonate complex as shown by facies-diagnostic microfossils (foraminifera, calcisphaeres, calcareous algae, microproblematica). The fossils as well as the other dominating grain types (lumps, peloids) point to source areas located within lagoonal and slope environments. Reef-derived material is rare. The turbidites exhibit four microfacies types, differentiated by composition and size of the grains as well as by micrite content and corresponding to the common vertical and lateral textural variation of limestone turbidites. These MF types were recognized in outcrops as well as from building stones used in building the St. Pankratius church in Eslohe-Reiste (northern Sauerland) in 1849 and in the renovation of the church in 1963/64. The comparison of microfacies and the degree of the destruction of ‘old’ and ‘new” building stones by weathering (macroscopically described by the ◂Fabric Index’: Product of the ‘Rock Destruction Risk’ and the ‘Rock Preparation Destruction Degree’) shows that intrabioclastic rudstones (MF type 1) and bioclastic grainstones (MF type 2), both characterizing the basal parts of the turbidite beds, are more resistant to weathering destruction originating from freezing and thawing than packstones (MF type 4). Weathering of micritic facies types (e.g., MF 4) is more intensive due to the stronger development of joint systems affecting not only the surface of the building stones but the entire dimension stone. Porosity or the existence and amount of stylolites seem to have had no significant impact on the weathering of the building stones studied. The stronger weathering of building stones used in the original construction of the church as compared with the stones applied in this century is caused by the greater time interval available for mechanical weathering connected with freezing and thawing. The consideration of microfacies of limestone turbidites should facilitate the exploitation of weathering-resistant carbonate building stones.     

Quantitative Risk Assessment of Trichloroethylene for a Former Chemical Works in Shanghai,China

Assessment of the potential risks posed by chlorinated solvents in groundwater is the key to establish the extent of the contamination and derive achievable remedial targets should remediation deems necessary. This article first presents the application of the American Society for Testing and Materials (ASTM) Risk Based Corrective Actions (RBCA) Guidance to quantitatively evaluate human health and environmental risk for a former chemical works in Shanghai, China. The observed maximum trichloroethylene (TCE) concentration in groundwater at the site reached 1220 mg/l that exceeded its solubility of 1070 mg/l at 10°C (Soil annual average temperature is 10°C in Shanghai). The maximum concentration for cis-1, 2-DCE (DCE) was also found to be elevated at 264 mg/l. A critical exposure pathway was considered to be indoor vapor intrusion of TCE into the buildings with excess lifetime cancer risk for children being 1.7 × 10^?3. This cancer risk exceeded regulatory limits of 1 × 10^?4 to 1 × 10^?6 for The Netherlands, the United Kingdom, and the United States. The calculated groundwater remedial targets for TCE and DCE are 7 mg/l and 904 mg/l, respectively, in order to protect child residents from inhalation of indoor vapors within the close proximity of the source area.     

Eco-Floristic studies of native plants of the Beer Hills along the Indus River in the districts Haripur and Abbottabad,Pakistan

The present study was conducted to elaborate vegetation composition structure to analyze role of edaphic and topographic factors on plant species distribution and community formation during 2013–14. A mixture of quadrat and transect methods were used. The size of quadrat for trees shrubs and herbs were 10 × 5, 5 × 2, 1 × 1 meter square respectively. Different phytosociological attribute were measured at each station. Primary results reported 123 plant species belong to 46 families. Asteraceae and Lamiaceae were dominant families with 8 species each. PCORD version 5 were used for Cluster and Two Way Cluster Analyses that initiated 4 plant communities within elevation range of 529–700 m from sea level. Indicator species analyses (ISA) were used to identify indicator species of each community. CANOCO Software (version 4.5) was used to measure the influence of edaphic and topographic variables on species composition, diversity and community formation. Whereas Canonical Correspondence Analysis (CCA) was used to measure the effect of environmental variables which showed elevation and aspect were the stronger environmental variable among topographic and CaCO₃ contents, electric conductivity, soil pH were the stronger edaphic factors in determination of vegetation and communities of the Bheer Hills. Grazing pressure was one of the main anthropogenic factors in this regard.     

谷子幼苗对土壤铅、铬的生长响应及吸收积累的差异性

采用盆栽土培试验,研究了谷子幼苗对土壤中不同含量铅（Pb）、铬（Cr）的生长响应和吸收积累的差异性。结果表明,在所试浓度（50～800 mg·kg^-1）范围内,Pb、Cr在谷子幼苗地上部和地下部的积累量存在较大差异,幼苗重金属的吸收富集和转运系数均为Pb大于Cr、Pb、Cr胁迫对幼苗生物量的影响表现为低浓度的促进和高浓度的抑制作用,但Cr对生物量的影响比Pb更强。相同处理条件下,幼苗茎叶中可溶性蛋白质、DNA含量和增色效应对Pb、Cr的响应也有明显差别,Cr对幼苗的生理毒性和DNA损伤效应的作用强度大于Pb。     

大鼠肝生长发育过程中ACP、AKP、HSC70/HSP68和PCNA的变化(英文)

磷酸酶（ＡＣＰ、ＡＫＰ）在生物的机能分化中起重要作用,热休克蛋白（ＨＳＰｓ）是近几年发现的一类在胚胎发育、细胞生存中起重要作用的分子,无论是胚胎发育还是细胞结构和功能构建都和细胞增殖密切相关,增殖细胞核抗原（ＰＣＮＡ）是检测细胞增殖的良好指标。 本实验用组织化学、免疫组织化学、Ｗｅｓｔｅｒｎ印迹、酶的原位复性电泳、体视学分析等方法定性和定量分析了酸性磷酸酶（ＡＣＰ）（Ｆｉｇ．１＆２）、碱性磷酸酶（ＡＫＰ）（Ｆｉｇ．４＆５）、构成性热休克蛋白 ７０／诱导性热休克蛋白 ６８（ＨＳＣ７０／ＨＳＰ６８）（Ｆｉｇ．６）和ＰＣＮＡ（Ｆｉｇ．７＆８, Ｔａｂｌｅ１）在大鼠肝生长发育（从１４天胚胎到成体）过程中的动态变化。结果表明：（１）在大鼠肝生长发育过程中,ＡＣＰ有两个活性高峰期,其时段处于大鼠吃奶和吃饲料起始期（Ｆｉｇ．１＆２）;（２）在ＡＣＰ的第一个活性高峰期时,ＡＫＰ活性降低;而在ＡＣＰ的第二个活性高峰期时,正值ＡＫＰ的活性高峰期（Ｆｉｇ．３）;（３）ＡＣＰ活性高峰期也是ＰＣＮＡ含量高峰期;（４）ＨＳＣ７０／ＨＳＰ６８在刚断奶的幼鼠肝和成体肝中表达量较多,其他时段表达极少。根据上述结果推测：ＡＣＰ和ＰＣＮＡ通过调节细     

Genomic,molecular evolution,and expression analysis of NOX genes in soybean (Glycine max)

Reactive oxygen species (ROS) are versatile signaling molecules in sensing stresses and play critical roles in signaling and development. Plasma membrane NADPH oxidases (NOXs) are key producers of ROS, and play important roles in the regulation of plant-pathogen interactions. Here, we performed a comprehensive analysis of the NOX gene family in the soybean genome (Glycine max) and 17 NOX (GmNOX) genes were identified. Structural analysis revealed that the GmNOX proteins in soybean were as conserved as those in other plants. 8 duplicated gene pairs were formed by a Glycine-specific whole-genome duplication (WGD) event approximately 13 million years ago (Mya). The Ka/Ks ratios of GmNOX genes ranged from 0.04 to 0.28, suggesting that the GmNOX family had undergone purifying selection in soybean. Gene expression patterns showed different expression of these duplicate genes, suggesting that the GmNOXs were retained by substantial subfunctionalization during the soybean evolutionary processes. Subsequently, the expression of GmNOXs in response to drought and phytohormones were characterized via qPCR. Importantly, four GmNOXs showed strong expression in nodules, pointing to their probable involvement in nodulation. Thus, our results shed light on the evolutionary history of this family in soybean and contribute to the functional characterization of GmNOX genes in soybean.     

Tolerance of Borya nitida,a poikilohydrous angiosperm,to heat,cold and high-light stress in the hydrated state

Borya nitida Labill., a plant able to colonize rock outcrops and shallow sands in areas of high incident solar radiation in Western Australia, was examined for its tolerance to extremes of temperature, and to intense visible radiation. Stress injury to the leaves from heat, chilling or photoinhibitory light was followed by the decrease in in-vivo variable chlorophyll fluorescence. Heat injury was also ascertained by an increase in the constant fluorescence. Borya nitida leaves were extremely heat tolerant when heated at 1° C min^-1. In-vivo variable chlorophyll fluorescence was detectable up to 55° C, several degrees higher than either maize or barley which are, respectively, adapted to warm and cool climates. An increase in constant fluorescence occurred above 50° C in B. nitida. This compares with values in the literature of 48–49° C for three desert plants from Death Valley, California, and 44–48° C for ten species of tropical plants. Unlike the Death-Valley plants, the high degree of heat tolerance found in B. nitida did not require prior acclimation by growth at high temperatures. Borya nitida was also tolerant of a chilling temperature of 0° C. Plants grown at a low photon fluence rate (120 mol m^-2s^-1) were irreversibly photoinhibited by light at 650 mol m^-2s^-1. Plants grown in sunlight resisted photoinhibition; however, the capacity to withstand photoinhibition was no greater than that of plants from less extreme environments.     

The kinetics of type 1 phytochrome in green,light-grown wheat (Triticum aestivum L.)

The kinetics of type 1 phytochrome were investigated in green, light-grown wheat. Phytochrome was measured by a quantitative sandwich enzyme-linked immunosorbent assay using monoclonal antibodies. The assay was capable of detecting down to 150 pg of phytochrome. In red light, rapid first-order destruction of the far-red-light-absorbing form of phytochrome (Pfr) with a half-life of 15 min was observed. Following white light terminated by red, phytochrome synthesis was delayed in darkness by about 15 h compared to plants given a terminal far-red treatment. Synthesis of the red-light-absorbing form of phytochrome (Pr) was zero-order in these experiments. Phytochrome synthesis in far-red light was approximately equal to synthesis in darkness in wheat although net destruction occurred in light-grown Avena sativa tissues in continuous far-red light, as has been reported for other monocotyledons. In wheat, destruction of Pfr apparently did not occur below a certain threshold level of Pfr or Pfr/total phytochrome. These results are consistent with an involvement of type 1 phytochrome in the photoperiodic control of flowering in wheat and other long-day plants.Abbreviations ELISA enzyme-linked immunosorbent assay - FR far-red light - HIR high-irradiance response - Pfr farred-light-absorbing form of phytochrome - Pr red-light-absorbing form of phytochrome - Ptot total phytochrome (Pr + Pfr) - R red light The authors wish to thank Prof. Daphne Vince-Prue (University of Reading) for many helpful discussions regarding this work. Hugh Carr-Smith was supported by a Science and Engineering Research Council studentship and Chris Plumpton by an Agricultural and Food Research Council (AFRC) studentship. B. Thomas and G. Butcher were supported by the AFRC.     

Circadian rhythm and fast responses to blue light of photosynthesis in Ectocarpus (Phaeophyta,Ectocarpales)

Photosynthesis of Ectocarpus siliculosus (Dillwyn) Lyngb. under continuous saturating red irradiation follows a circadian rhythm. Blue-light pulses rapidly stimulate photosynthesis with high effectiveness in the troughs of this rhythm but the effectiveness of such pulses is much lower at its peaks. In an attempt to understand how blue light and the rhythm affected photosynthesis, the effects of inorganic carbon on photosynthetic light saturation curves were studied under different irradiation conditions. The circadian rhythm of photosynthesis was apparent only at irradiances which were not limiting for photosynthesis. The same was found for blue-light-stimulated photosynthesis, although stimulation was observed also under very low red-light irradiances after a period of adaptation, provided that the inorganic-carbon concentration was not in excess. Double-reciprocal plots of light-saturated photosynthetic rates versus the concentration of total inorganic carbon (up to 10 mM total inorganic carbon) were linear and had a common constant for half-saturation (3.6 mM at pH 8) at both the troughs and the peaks of the rhythm and before and after blue-light pulses. Only at very low carbon concentrations was a clear deviation found from these lines for photosynthesis at the rhythm maxima (red and blue light), which indicated that the strong carbon limitation specifically affected photosynthesis at the peak phases of the rhythm. Very high inorganic carbon concentrations (20 mM) in the medium diminished the responses to blue light, although they did not fully abolish them. The kinetics of the stimulation indicate that the rate of photosynthesis is affected by two blue-light-dependent components with different time courses of induction and decay. The faster component seemed to be at least partially suppressed at red-light irradiances which were not saturating for photosynthesis. Lowering the pH of the medium had the same effects as an increase of the carbon concentration to levels of approx. 10 mM. This indicates that Ectocarpus takes up free CO₂ only and not bicarbonate, although additional physiological mechanisms may enhance the availability of CO₂.Abbreviation TIC total inorganic carbon     

Esterase isozyme polymorphism, specific and nonspecific esterase, syngenic lines development and natural occurrence of a thermostable esterase in the tropical silkworm Bombyx mori L.

Esterase isozyme polymorphism was documented for digestive juice and haemolymph of the tropical multivoltine silkworm, Bombyx mori L., breed CB5 (GP) and its syngenic lines (CB5Lm^e-1, CB5Lm-2 and CB5Lm-5) using α- and β-naphthylacetate separately as nonspecific substrates (Ogita, Z., Kasai, T., 1965. Genetico-biochemical analysis of specific esterases in Musca domestica. Jpn. J. Genet. 40, 173–184). Polymorphism existed in the isozyme pattern of α-esterase with two or three bands in digestive juice and three to five bands in haemolymph. No polymorphism was observed in β-esterase isozyme pattern having four bands in digestive juice and two bands in haemolymph. During the course of esterase isozyme studies, the presence of some specific α-esterase bands (Est-1, 4 and 5) in haemolymph and β-esterase bands (Est-1, 2 and 3) in digestive juice were observed. But both α- and β-esterase bands Est-3 and 4 in digestive juice and Est-2 and 3 in haemolymph were found to be nonspecific. Nonspecific β-esterase band (Est-3) in haemolymph of CB5 (GP) and its syngenic lines withstood a temperature up to 80±1°C for 10 min. No thermostable band was observed in the isozyme zymogram of α-esterase in digestive juice and haemolymph or β-esterase in digestive juice. Overall, this study discusses the presence of esterase heterogeneity in the CB5 (GP) genepool, syngenic lines development, occurrence of specific α- and β-esterase bands in digestive juice and haemolymph and thermostable β-esterase band Est-3 in haemolymph in tropical silkworm Bombyx mori L.     

Comparisons of phylogenetic hypotheses among different data sets in dwarf dandelions (Krigia,Asteraceae): Additional information from internal transcribed spacer sequences of nuclear ribosomal DNA

The internal transcribed spacer (ITS) region of the 18 S–25 S nuclear ribosomal DNA repeat was sequenced from 19 populations of the tribeLactuceae, including all species of dwarf dandelion (Krigia) and five outgroup genera. The incidence of length changes and base substitutions was at least two times higher for ITS 1 than ITS 2. Interspecific sequence divergence withinKrigia averaged 9.62% (1.61%–15.19%) and 4.26% (0%–6.64%) in ITS 1 and ITS 2, respectively. Intergeneric sequence divergence ranged from 15.6% to 44.5% in ITS 1 and from 8.0% to 28.6% in ITS 2. High sequence divergence and homoplasy among genera of tribeLactuceae suggest that the phylogenetic utility of ITS sequence data is limited to interspecific studies or comparisons among closely related genera. Trees generated from ITS sequences are essentially identical to those from restriction site comparisons of the entire nuclear ribosomal (nr) DNA region. The degree of tree resolution differed depending on how gaps were treated in phylogenetic analyses. The ITS trees were congruent with the chloroplast DNA and morphological phylogenies in three major ways: 1) the sister group relationship betweenKrigia andPyrrhopappus; 2) the recognition of two monophyletic sections,Krigia andCymbia, in genusKrigia; and 3) the monophyly of theK. occidentalis-K. cespitosa clade in sect.Cymbia. However, the two nrDNA-based trees are not congruent with morphology/chloroplast DNA-based trees for the interspecific relationships in sect.Krigia. An average of 22.5% incongruence was observed among fourKrigia data sets. The relatively high degree of incongruence among data sets is due primarily to conflict between trees based on nrDNA and morphological/cpDNA data. The incongruence is probably due to the concerted evolution of nrDNA repeating units. The results fromKrigia and theLactuceae suggest that nrDNA data may have limited utility in phylogenetic studies of plants, especially in groups which exhibit high levels of sequence divergence. Our combined phylogenetic analysis as a total evidence shows the least conflict to each of the individual data sets.     

Changes in germination and respiratory potential of embryos of dormant Grand Rapids lettuce seeds during long-term imbibed storage,and related changes in the endosperm

Grand Rapids lettuce (Lactuca sativa L.) seeds were stored in an imbibed state for up to two years. Embryos dissected from stored seeds showed a progressive loss with time in their ability to germinate on polyethylene glycol (PEG) solutions. Little germination of dissected embryos from one-month imbibed seeds occurred on-6 bar PEG but only after four months of storage did the dissected embryos fail to germinate on-4 bar PEG. After two years storage 30% of dissected embryos still were able to germinate on-2 bar PEG. This loss of germination potential, which may be a symptom of the development of an embryo dormancy, could be reversed by N⁶-benzyladenine (BA) and red light (R) applied together or separately to dissected embryos. Two weeks of chilling of 12-month imbibed seeds restored sensitivity to R and a 48-h BA pretreatment prior to R resulted in germination rates similar to those of seeds emerging from primary dormancy. There was loss of embryo control of endo--mannanase activity after two weeks of storage even though the endosperms themselves retained their capacity for enzyme synthesis for six more weeks. Eventually, then, endo--mannanase synthesis is not possible because of inherent changes in both the embryo and endosperm, although each tissue undergoes changes at its own rate. Oxygen uptake by embryos dissected from two-month imbibed seeds did not increase to the same extent as embryos dissected from freshly imbibed seeds. In intact seeds germinating from a skotodormant state, oxygen uptake increased at a time coincident with radicle protrusion, but did not achieve the levels of uptake of those seeds germinating from a primary dormant state. The decline in uptake of oxygen by secondary dormant seeds is the result of a lowered respiratory capability of the embryo itself, rather than of changes in permeability of the surrounding structures.Abbreviations BA N⁶-benzyladenine - Pfr active (far-redabsorbing) form of phytochrome - R red light - PEG polyethylene glycol