Different sensitivity of Phragmites australis and Glyceria maxima to high availability of ammonium-N

The ability to cope with NH₄⁺-N was studied in the littoral helophytes Phragmites australis and Glyceria maxima, species commonly occupying fertile habitats rich in NH₄⁺ and often used in artificial wetlands. In the present study, Glyceria growth rate was reduced by 16% at 179 μM NH₄⁺-N, and the biomass production was reduced by 47% at 3700 μM NH₄⁺-N compared to NO₃⁻-N. Similar responses were not found in Phragmites. The amounts (mg g⁻¹ dry wt) of starch and total non-structural carbohydrates (TNC) in rhizomes were significantly lower in NH₄⁺ (8.9; 12.2 starch; 20.1; 41.9 TNC) compared to NO₃⁻ treated plants (28.0; 15.6 starch; 58.5; 56.3 TNC) in Phragmites and Glyceria, respectively. In addition, Glyceria showed lower amounts (mg g⁻¹ dry wt) of soluble sugars, TNC, K⁺, and Mg²⁺ in roots under NH₄⁺ (5.6; 14.3; 20.6; 1.9) compared to NO₃⁻ nutrition (11.6; 19.9; 37.9; 2.9, for soluble sugars, TNC, K⁺, and Mg²⁺, respectively), while root internal levels of NH₄⁺ and Ca²⁺ (0.29; 4.6 mg g⁻¹ dry wt, mean of both treatments) were only slightly affected. In Phragmites, no changes in soluble sugars, TNC, Ca²⁺, K⁺, and Mg²⁺ contents of roots (7.3; 14.9; 5.1; 17.3; 2.6 mg g⁻¹ dry wt, means of both treatments) were found in response to treatments. The results, therefore, indicate a more pronounced tolerance towards high NH₄⁺ supply in Phragmites compared to Glyceria, although the former may be susceptible to starch exhaustion in NH₄⁺-N nutrition. In contrast, Glyceria's ability to colonize fertile habitats rich in NH₄⁺ is probably related to the avoidance strategy due to shallow rooting or to the previously described ability to cope with high NH₄⁺ levels when P availability is high and NO₃⁻ is also provided.     

Growth and metabolism of Typha species in relation to cutting treatments

Container and field experiments, in which Typha latifolia L. and Typha angustifolia L. were cut either above or below the water level, were conducted to determine the physiological basis for reports that the latter treatment was more effective as a control measure. In containers, measurements of oxygen concentrations within the aerenchyma of the rhizome both with an oxygen electrode and by gas chromatography showed that oxygen could diffuse very readily to plant parts growing in an anoxic environment if there was a small amount of leaf or cut plant stem growing above the water level. When all shoots were cut below water, the oxygen in submersed plant parts was rapidly consumed and anaerobic respiration resulted in the production of ethanol. Lactate or elevated malate levels were not found. The below-water biomass decayed rapidly under these conditions and the plants had a much lower regenerative ability than plants cut above water where oxygen continued to reach the roots and rhizomes. In the field, three cuts during the growing season below water were sufficient to kill nearly all the underwater biomass; similar cuts above water reduced the total biomass compared with uncut plants, but much of the underwater biomass remained healthy and able to regenerate.     

Sesquiterpenoids of Riccardia and Pallavicinia species

Riccardia species (Metzgeriales) contain various types of sesquiterpenes. R. jackii produces ent-selinane-, ent-aromadendrane-and ent-bicyclogermacrane-type sesquiterpenes together with (R)-cuparene and α-barbatene. Aneura pinguis (= Riccardia pinguis) is chemically quite different from R. multifida and R. jackii. The former produces a large amount of pinguisone. R. multifida contains 6-(3-methyl-2-butenyl)-indole and (+)-β-elemene as the major components. Pallavicinia longispina (Dilaenaceae; Metzgeriales) produces mainly spathulenol. The chiral properties of the sesquiterpenes isolated from R. jackii are quite similar to those of red algae, Laurencia species.     

Bioassays with Stigeoclonium Kütz. (Chlorophyceae) to identify nitrogen and phosphorus limitations

Eleven strains of the filamentous algae genus Stigeoclonium Kütz. (Chlorophyceae) were tested as bioassay organisms to identify nitrogen and phosphorus limitations to growth in a variety of waters. The assay results were related to the nutrient status of the waters during the year. Optimal growth was obtained at an inorganic phosphorus concentration of 0.65 mg P 1^?1 and an inorganic nitrogen concentration of 3.75 mg N 1^?1. The algal growth potentials were generally higher in November and February than in August. In summer, nitrogen became important as a limiting nutrient. When ratios of inorganic nitrogen to inorganic phosphorus (N/P) were above 6.2, phosphorus was primarily limiting and at lower N/P ratios nitrogen became the important limiting factor. Stigeoclonium proved to be a suitable bioassay organism to identify nutrient limitation in freshwaters.     

Growth and development of the Angoumois grain moth, Sitotroga cerealella in an artificial diet

A simple method for rearing the Angoumois grain moth, Sitotroga cerealella, in an artificial diet is described. Although the larvae normally feed within grain kernels, they readily became established in pellets containing a mixture of five natural products. An evaluation of the growth rate in this medium revealed a marked sex difference. The males attained a maximum mean larval weight of 7·2 mg at 22 days compared with 12·3 mg for mature females at 24 days. Both sexes were found to pass through four larval instars. A study of the pupation rate showed that males reached 50 per cent pupation a full 5 days before females. While both sexes spent about 6·7 days in the pupal-pharate adult stage, the mean weight of newly-ecdysed female adults was 77 per cent greater than that of the males.     

Surface wax of Andreaea and Pogonatum species

The mosses Andreaea rupestris, Pogonatum aloides and P. urnigerum contain surface waxes in amounts of 0.05–0.12% dry wt. The waxes consisted of esters (C₃₈-C₅₄), primary alcohols (C₂₀-C₃₂), free fatty acids (C₁₆-C₃₀), and alkanes (C₂₁-C₃₁). Additionally, aldehydes (C₂₂-C₃₀) were major constituents in the wax of P. urnigerum. The classes and their chain length distributions in the surface waxes of these mosses are comparable to those of epicuticular waxes of higher plants.     

Alkaloids of formosan Fissistigma and Goniothalamus species

Separation of the basic fractions from Formosan Fissistigma glaucescens, F. oldhamii and Goniothalamus amuyon afforded one new quaternary phenanthrene alkaloid, N-methylatherosperminium (15), along with the known alkaloids, (?)-discretamine (1), (?)-tetrahydropalmatine (2), palmatine (3), (?)-asimilobine (4), (?)-norannuradhapurine (5), (?)-crebanine (6), (?)-calycinine (fissoldine, fissistigine A) (7a), (?)-anolobine (8), (?)-xylopine (9), (?)-anonaine (10a), oxocrebanine (11), liriodenine (12), atherosperminine (13), N-noratherosperminine (14) and (+)-O-methylflavinantine (O-methylpallidine) (16).     

Iridoids and alkanes in twelve species of Galium and Asperula

The results of an analysis of the iridoid and n-alkane patterns in twelve species of Asperula and Galium revealed similarities rather than differences between and within the genera. The ease with which artefacts can be produced from asperuloside limits the taxonomic usefulness of asperuloside-type iridoids. A sub-division of the genus Galium based on the dominant alkanes was not completely in accord with the existing division of the genus into sections. The alkane patterns are largely unaffected by plant age or geographical location. They do support some of the taxonomic views currently held concerning the inter-relationships of different species in the genus Galium.     

Hebeloma species associated with Cistus

The genus Hebeloma has a number of species highly specific to Cistus and others that occur with several host genera. This paper discusses the species of Hebeloma that appear to be ectomycorrhizal with Cistus, judging from their occurrence when Cistus is the only available host. The previously unknown species H. plesiocistum spec. nov. is described. We also provide a key to the known Hebeloma associates of Cistus. Molecular analyses based on ITS sequence data further illustrate the distinctness of the newly described species and difficulties in the species delimitation with view to H. erumpens. Specific associations with Cistus may have evolved more than once within the genus Hebeloma.     

Anthraquinones in Digitalis species

Twenty anthraquinones have been found in the roots of Digitalis trojana of which the following are new: digitopurpone-1-methyl ether, ω-hydroxypacybasin and ω-hydroxyziganein. The biogenesis of the thirty anthraquinones now known in Digitalis s.l. is discussed.     

Benzisochromanquinones in ventilago species

From the acetone extract of the root bark of Ventilago maderaspatana eight new benzisochromanquinones; ventiloquinones A, B, C, D, E, F, G and H, have been isolated. Ventiloquinones I, J and K are three more new benzisochromanquinones isolated from the root bark of V. calyculata. The majority are 3,4,5,10-tetrahydro-cis-1,3-dimethyl-1H-naphtho[2,3-c]pyran-5,10-quinones related to eleutherin, but F, H, I, J and K are 6,9-quinones related to ventilagone.     

Naphthaquinones in Lomatia species

Lomatiol, juglone, β-hydrojuglone and naphthazarin have been found distributed in various parts of six Lomatia spp. Three others contained no quinonoid pigments but the leaves of L. dentata yielded kaempferol-3-methyl ether and quercetin-3-methyl ether.     

Anthraquinones in Ventilago species

Eleven anthraquinones have been isolated from the root bark of Ventilago calyculata of which xanthorin-5-methyl ether and 2-hydroxyislandicin are n     

Demography, reproduction, and dormancy along altitudinal gradients in three intermountain Allium species with contrasting abundance and distribution

Little is known about the variation in demographics, flower number, fruit set, and summer dormancy in Allium species native to the Intermountain West region of the United States. The purpose of this study was to investigate demographic patterns, summer dormancy traits, and variation in reproductive characteristics among habitats. Three populations of each of three species, Allium acuminatum, A. brandegei, and A. passeyi, were studied along an altitudinal gradient in northern Utah, USA, from 2004 to 2006. Demographic data were collected from individuals in permanent plots established in each population. Individual flowering plants were periodically monitored and used to calculate reproductive characteristics. Leaf area measurements throughout the 2005 growing season and soil temperature sensors were used to assess the relationship between habitat and dormancy characteristics. Populations of the widely distributed species, A. acuminatum and A. brandegei, were dominated by individuals in seedling and flowering stages while the restricted A. passeyi had populations containing a majority of individuals in the post-seedling, but non-flowering stage-class. There was a strong directional trend in A. acuminatum reproductive traits, with flower number and fruit set decreasing with increasing elevation. The mid-elevation A. brandegei populations were reproductively more successful than the high and low-elevation populations. The high-elevation A. passeyi population had more flowers per plant and higher fruit set in comparison to the lower elevation populations. The onset of summer dormancy as indicated by the timing of leaf senescence, was associated with high soil temperatures specific to each species. In general, the timing of leaf senescence was later in higher elevation populations in all species. A smaller proportion of non-flowering individuals in A. acuminatum and A. brandegei may indicate a high seedling mortality rate or a shorter juvenile phase in comparison to A. passeyi. The A. passeyi populations exhibit demographic characteristics of rare taxa; low seed production and low seedling recruitment. The high number of non-flowering plants in A. passeyi likely includes many reproductively mature individuals which are influenced by the unique habitat and environment of this species. Temperature is likely the key environmental cue inducing summer dormancy in all three species.     

Extracytoplasmic phosphatases of selected species of Saccharomyces, Kluyveromyces and Rhodotorula

Phosphatase activities of yeasts belonging to the genera Saccharomyces, Kluyveromyces and Rhodotorula were studied. Rhodotorula rubra exhibited activities at acid, neutral and alkaline pH; the other yeasts only had activity at acid pH. Growing yeasts in a constant pH (4.5) medium decreased phosphatase activities in Saccharomyces and Kluyveromyces, while neutral activity was enhanced in Rhodotorula rubra which excreted more enzyme under these conditions. Washing cells with sucrose solutions lowered phosphatase activities in all yeasts, due to enzyme liberation. Acid phosphatase activities in isolated and purified cell walls were very small. Phosphatases thus appear not to be strongly bound to yeast cell walls.     

Taxonomy and species delimitation in Cryptosporidium

Amphibians, reptiles, birds and mammals serve as hosts for 19 species of Cryptosporidium. All 19 species have been confirmed by morphological, biological, and molecular data. Fish serve as hosts for three additional species, all of which lack supporting molecular data. In addition to the named species, gene sequence data from more than 40 isolates from various vertebrate hosts are reported in the scientific literature or are listed in GenBank. These isolates lack taxonomic status and are referred to as genotypes based on the host of origin. Undoubtedly, some will eventually be recognized as species. For them to receive taxonomic status sufficient morphological, biological, and molecular data are required and names must comply with the rules of the International Code for Zoological Nomenclature (ICZN). Because the ICZN rules may be interpreted differently by persons proposing names, original names might be improperly assigned, original literature might be overlooked, or new scientific methods might be applicable to determining taxonomic status, the names of species and higher taxa are not immutable. The rapidly evolving taxonomic status of Cryptosporidium sp. reflects these considerations.     

长白山红松臭冷杉光谱反射随海拔的变化

为了研究红松、臭冷杉光谱反射率随海拔梯度的变化,本研究使用光谱仪测量了长白山两种主要的针叶树种红松、臭冷杉不同海拔针叶的光谱反射率,分别对比了两个树种不同海拔间光谱反射率、光谱指数的差异,这些特征可以反映植物叶片色素组成和色素含量等信息。结果表明：两种针叶树在不同海拔的光谱反射率变化明显,光谱指数也有显著差异,证明相关生理状况发生明显变化。对比各海拔光谱反射率发现,1279m处红松、臭冷杉针叶的色素总含量较高,叶绿素指数反映出748m处红松、臭冷杉针叶叶绿素含量显著高于1040m和1279m处,Car：Chl指数的差异说明红松、臭冷杉均在748处受到较弱的胁迫,臭冷杉在1040m受到较强的胁迫,对比各波段反射率随海拔的变化,发现红松、臭冷杉针叶色素含量都随海拔变化有明显的变化,而且臭冷杉的叶片水分含量、叶片结构也可能容易受到海拔影响。     

Role of svp in Drosophila Pericardial Cell Growth

The Drosophila dorsal vessel is a segmentally repeated linear organ, in which seven-up (svp) is expressed in two pairs of cardioblasts and two pairs of pericardial cells in each segment. Under the control of hedgehog (hh) signaling from the dorsal ectoderm, svp participates in diversifying cardioblast identities within each segment. In this experiment, the homozygous embryos of svp mutants exhibited an increase in cell size of Eve positive pericardial cells (EPCs) and a disarranged expression pattern, while the cardioblasts pattern of svp-lacZ expression was normal. In the meantime, the DA1 muscle founders were absent in some segments in svp mutant embryos, and the dorsal somatic muscle patterning was also severely damaged in the late stage mutant embryos, suggesting that svp is required for the differentiation of Eve-positive pericardial cells and DA1 muscle founders and may have a role in EPC cell growth.