Precursors of Asparagine in Lupins

Fumaric acid-1,4-¹⁴C, L-aspartic acid-4-¹⁴C, and glycine-2-¹⁴Cwere supplied for 1 to 3 h to etiolated lupin shoots that wererapidly synthesizing asparagine. The distribution of ¹⁴C inaspartate and asparagine isolated from this material was determined.With aspartic acid-4-¹⁴C adminstration radioactivity was mostlyin carbons 1 and 4 with carbon 4 having the greater amount;with fumaric acid 1,4-¹⁴C administration, radioactivity wasagain mostly in carbons 1 and 4. Aspartate labelled by fumaratecontained relatively more radioactivity in carbons 2 and 3.Little radioactivity from glycine-2-¹⁴C entered either aspartateor asparagine and this was mainly in carbon 2 and 3. It is concludedthat asparagine synthesis form aspartate is a major pathwayof asparagine biosynthesis in lupins.     

The Relationship Between Cyanide Assimilation and Asparagine Biosynthesis in Lupins

ß-cyanoalanine synthese in etolated seedlings of Lupinusangustifolius is found mainly in the mitochondrial fractionof the cotyledons and stems. In seedlings developing at 25°Cin the dark it reaches a maximal concentration after 5 days,at the same time as asparagine accumulation is most rapid andother physiological changes occur. However, maximal abiliatyto assimilate HCN gas to asparagine develops after 3 to 4 days,before asparagine accumulation begins. The possibility thatthe ß-cyanoalanine pathway is a major route for asparaginebiosynthesis in lupin seedlings is concluded to be unlikely.     

The Urban Funnel Model and the Spatially Heterogeneous Ecological Footprint

Urban ecological systems are characterized by complex interactions between the natural environment and humans at multiple scales; for an individual urban ecosystem, the strongest interactions may occur at the local or regional spatial scale. At the regional scale, external ecosystems produce resources that are acquired and transported by humans to urban areas, where they are processed and consumed. The assimilation of diffuse human wastes and pollutants also occurs at the regional scale, with much of this process occurring external to the urban system. We developed the urban funnel model to conceptualize the integration of humans into their ecological context. The model captures this pattern and process of resource appropriation and waste generation by urban ecosystems at various spatial scales. This model is applied to individual cities using a modification of traditional ecological footprint (EF) analysis that is spatially explicit; the incorporation of spatial heterogeneity in calculating the EF greatly improves its accuracy. The method for EF analysis can be further modified to ensure that a certain proportion of potential ecosystem services are left for in situ processes. Combining EF models of human appropriation with ecosystem process models would help us to learn more about the effects of ecosystem service appropriation. By comparing the results for food and water, we were able to identify some of the potentially limiting ecological factors for cities. A comparison of the EFs for the 20 largest US cities showed the importance of urban location and interurban competition for ecosystem services. This study underscores the need to take multiple scales and spatial heterogeneity into consideration to expand our current understanding of human–ecosystem interactions. The urban funnel model and the spatially heterogeneous EF provide an effective means of achieving this goal. Received 17 October 2000; accepted 31 May 2001.     

大豆品种中黄55不同复叶的小叶组成及其分布特点

本研究对大豆品种中黄55的复叶类型及不同种植地点各种复叶类型分布及其着生节位进行了研究,旨在探明多小叶的变化规律。根据组成复叶中小叶的数目,可分为7类,按照侧生和顶生叶片的数量进一步分为13种叶型,其中,4类共5种叶型尚未见报道。中黄55的复叶以三出复叶为主,其它复叶的小叶数以“4叶D1型”比率较高,随着纬度的降低,复叶类型数减少;北京顺义、湖北武汉和海南三亚3个地点间各小叶型比率方差分析表明,大部分小叶型比率3点间差异显著,表明复叶小叶型及其比率受环境的影响;主茎上从低节位至高节位,普通三出复种的比率先是降低,然后再升高,而不同节位分枝的普通三出复叶的比率变化不大。通过本研究可拓宽对大豆复叶小叶型的认识。     

Micronutrient Deficiency Influences Plant Growth and Activities of Superoxide Dismutases in Narrow-leafed Lupins

The effect of copper (Cu), zinc (Zn) or manganese (Mn) deficiencyon the growth and activity of superoxide dismutase (SOD) formswas investigated in seedlings of narrow-leafed lupins (LupinusangustifoliusL.). Plants grown without Zn developed Zn deficiencysymptoms 24 d after sowing (DAS), and those grown without Mnshowed Mn deficiency symptoms 31 DAS. However, plants grownwithout Cu did not show visible leaf symptoms. Shoot dry weightwas decreased by Zn and Mn deficiency 24 DAS, and by Cu deficiency31 DAS. Soluble protein concentration was reduced considerablyby Zn deficiency 24 DAS, but was not affected by Cu deficiencyuntil 31 DAS. In contrast, soluble protein concentration inMn-deficient plants was higher than in control plants 31 DAS.Shoot concentration of micronutrients which were not suppliedto plants decreased significantly, with a simultaneous increasein concentration of one or more of the other nutrients analysed.The activities of total SOD, MnSOD and Cu/ZnSOD on a fresh weightbasis declined drastically in -Cu and -Zn plants 24 DAS. Onthe contrary, the activities of total SOD and Cu/ZnSOD on eithera fresh weight or soluble protein basis increased markedly in-Mn plants 24 DAS, and MnSOD activity increased significantlyin these plants 31 DAS. It was concluded that micronutrientdeficiency (Cu, Zn or Mn) altered the activities of SOD formsdepending on the kind and severity of the deficiency stress.Manipulation of the capacity of plants to tolerate oxidativestress may influence their capacity to tolerate micronutrientdeficiency.Copyright 1999 Annals of Botany Company. Copper,Lupinus angustifolius, manganese, deficiency, superoxide dismutase, zinc.     

Role of Calcium in Phytochrome-Controlled Nyctinastic Movements of Albizzia lophantha Leaflets

The involvement of Ca(2+) on phytochrome-controlled nyctinastic closure in Albizzia lophantha has been studied by testing the effect of the calcium ionophore 6S-[6alpha(2S(*),3S(*)),8beta(R(*)),9beta,11alpha]-5- methyl-amino)-2-[[3,9,11-trimethyl-8-[-1-methyl-2-oxo-2-(1H-pyrrol-2-yl) ethyl]-1,7-dioxaspiro[5.5]-undec-2yl] methyl]-4-benzoxazolecarboxylic acid (A23187) and the intracellular calcium antagonist 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8). An external supply of Ca(2+) or calcium ionophore A23187 to the Albizzia leaflets emulates the effect of red light irradiation and counteracts the inhibitory effect of far red light. The intracellular calcium antagonist TMB-8 supplied to Albizzia leaflets inhibits the effect of red light, but had no effect on far red irradiated plants. This suggests a dependence between phytochrome action and intracellular free Ca(2+). We suggest that calcium acts as a phytochrome messenger on control of ion fluxes that drive turgor changes in pulvinular motor cells.     

Factors affecting the Abscission of Reproductive Organs in Yellow Lupins (Lupinus luteus L.): I. THE EFFECT OF DIFFERENT PATTERNS OF FLOWER REMOVAL

1. The effect of various patterns of flower removal on pod settingwas investigated in Lupinus luteus L. Four-fifths, three-fifths,or two-fifths of the flowers of the main inflorescence wereremoved according to ten different patterns. 2. All flowers could produce pods but later ones were less efficientin doing so. Developing pods had an abscission-inducing effecton later flowers, which became increasingly effective towardsthe apical part of the inflorescence. More pods were retained when flowers on each consecutive whorlwere arranged in a spiral than when the same number was arrangedvertically. Pod setting was incomplete when the number of flowers per inflorescencewas reduced well below the total number of pods normally present. 3. The number of ovules in consecutive flowers gradually decreasedfrom an average of 5.7 at the base to 4.3 at the top of theinflorescence. The ratio of seeds to ovules fluctuated irregularlybetween 65 and 94 per cent, and did not indicate a general trendin embryo abortion. 4. The growth-rate of pods at the top of the inflorescence wasmuch slower than at the bottom. Vascular differentiation wasalmost absent at the top of the inflorescence when the flowerswere fertilized, and further vascular tissue was produced onlywhen flowers produced pods.     

Nutrient Uptake and Organic Acid Anion Metabolism in Lupins and Peas Supplied with Nitrate

Unlike many plants reported in the literature, lupins do notexcrete OH^- in amounts equivalent to the net excess of inorganicanion uptake over inorganic cation uptake. To investigate themechanisms involved in the maintenance of charge balance, nutrientuptake and organic anion accumulation of lupins and peas suppliedwith a range of NO^-₃ concentrations, were compared. Lupins absorbed less NO^-₃ than peas on a dry weight basis, whichlargely accounted for the smaller excess of anion uptake overcation uptake in lupins than in peas at the same NO^-₃ supply.When anion uptake exceeded cation uptake, peas excreted an equivalentcharge of OH^-, whereas lupins excreted much smaller amountsof OH^- than the excess of anion over cation uptake. It was calculatedthat lupins excreted significant amounts of organic anions whenanion uptake exceeded cation uptake, whereas organic anion excretionfrom peas was negligible, regardless of their NO^-₃ supply andcation-anion balance. In this study, organic anion excretion was measured from lupinroots grown in near-sterile conditions while supplied with NO^-₃at 0, 500 and 2000 µM. Although complete sterility wasnot achieved, there was close agreement between the organicanion excreted and the excess anion over cation uptake.Copyright1994, 1999 Academic Press Lupinus angustifolius L., Pisum sativum L., organic acid, nutrient uptake     

European Origin of Bradyrhizobium Populations Infecting Lupins and Serradella in Soils of Western Australia and South Africa

We applied a multilocus phylogenetic approach to elucidate the origin of serradella and lupin Bradyrhizobium strains that persist in soils of Western Australia and South Africa. The selected strains belonged to different randomly amplified polymorphic DNA (RAPD)-PCR clusters that were distinct from RAPD clusters of applied inoculant strains. Phylogenetic analyses were performed with nodulation genes (nodA, nodZ, nolL, noeI), housekeeping genes (dnaK, recA, glnII, atpD), and 16S-23S rRNA intergenic transcribed spacer sequences. Housekeeping gene phylogenies revealed that all serradella and Lupinus cosentinii isolates from Western Australia and three of five South African narrow-leaf lupin strains were intermingled with the strains of Bradyrhizobium canariense, forming a well supported branch on each of the trees. All nodA gene sequences of the lupin and serradella bradyrhizobia formed a single branch, referred to as clade II, together with the sequences of other lupin and serradella strains. Similar patterns were detected in nodZ and nolL trees. In contrast, nodA sequences of the strains isolated from native Australian legumes formed either a new branch called clade IV or belonged to clade I or III, whereas their nonsymbiotic genes grouped outside the B. canariense branch. These data suggest that the lupin and serradella strains, including the strains from uncultivated L.cosentinii plants, are descendants of strains that most likely were brought from Europe accidentally with lupin and serradella seeds. The observed dominance of B. canariense strains may be related to this species' adaptation to acid soils common in Western Australia and South Africa and, presumably, to their intrinsic ability to compete for nodulation of lupins and serradella.     

Synthesis of Chymotrypsin Inhibitor I Protein in Potato Leaflets Induced by Detachment

Chymotrypsin inhibitor I is a protein that can be induced to accumulate in potato leaflets within hr in the light when leaflets are detached from intact plants and supplied with water. This increase in inhibitor I is not accompanied by an increase in all proteins in the detached leaflets. The accumulation is polar, proceeding from the base of the leaflets toward the tip. Low inhibitor I levels can be effectively maintained in detached leaflets by supplying them either water in the dark or solutions of indole acetic acid or 2,4-dichlorophenoxy acetic acid in the light. Inhibitor I from leaflets is not identical to inhibitor I isolated from potato tubers as determined by immunochemical analyses.     

Occurrence of Six Begomoviruses Infecting Tomato Fields in Venezuela and Genetic Characterization of Potato Yellow Mosaic Virus Isolates

Begomoviruses are one of the major pathogens in tomato crops worldwide. In Venezuela, six begomovirus species have been described infecting tomato: Potato yellow mosaic virus (PYMV), Euphorbia mosaic Venezuela virus (EuMVV), Merremia mosaic virus (MeMV), Tomato chlorotic leaf distortion virus (ToCLDV), Tomato yellow margin leaf curl virus (TYMLCV) and Tomato yellow leaf curl virus (TYLCV). In this study, the occurrence of these viruses was analysed by PCR in 338 tomato plants exhibiting virus‐like symptoms. Sixty‐three per cent of the plants were positive at least to one of the begomoviruses tested. PYMV and TYLCV were the most frequent viruses showing 39.6 and 23.7% occurrence, respectively. Phylogenetic analyses revealed two groups of PYMV isolates from several Caribbean Basin countries. The first group clustered isolates from several countries, including Venezuela, and the second group clustered only Colombian isolates. Due to the high prevalence of PYMV and TYLCV in Venezuela, it is suggested that the surveillance and control strategies currently applied in the country should be focused on these two begomoviruses.     

Factors Affecting the Abscission of Reproductive Organs in Yellow Lupins (Lupinus luteus L.): III. ENDOGENOUS GROWTH SUBSTANCES IN VIRUS-INFECTED AND HEALTHY PLANTS AND THEIR EFFECT ON ABSCISSION

Extracts of small and mature-size lupin pods yielded four substancesaffecting the growth of wheat-coleoptile sections: one acidpromotor (A), two acid inhibitors(B and X), and one neutralinhibitor(Y). Inhibitor B was extremely active, however, coleoptile sectionsshowed no signs of toxic effects; they resumed growth at a rapidrate after rinsing them and adding ß-indolylaceticand (IAA) to the medium. 1 µg of IAA was required to counteractthe effect of ‘B’ extracted from 230 mg. Of tissue.On an equal fresh weight basis the inhibiting action of ‘B’in lupin pods was 500–1,500 times more potent than thatof ‘inhibitor ß’ in etiolated pea seedlings. Small pods of plants infected with pea-mosaic virus yielded3 times the amount of ‘A’ of healthy plants (equivalentto 1 µg. IAA 0.3 µg. IAA per 25 g. of tissue respectively),and approximately the amount of ‘B’. Mature podsof virus-infected plants again yielded more‘A’,but also 2? times more ‘B’ than pods of healthyplants. Healthy pods yielded more ‘A’ than virus-infectedpods, and there was no difference in ‘X’. A lupin abscission test was developed and the effects of proximaland distal application of -naphthyl acetic acid (NAA) are presented,and discussed with respect to results of other abscission tests. ‘A’ accelerated abscission when applied proximally,and delayed or prevented it when applied distally. ‘B’strongly accelerated abscission when applied in either way.A possible mechanism explaining the abscission-inducing effectof developing pods on later flowers is discussed in terms ofthe substances ‘A’ and ‘B’. The partlyprevented abscission observed on virus-infected plants was foundto agree well with the proposed mechanism.     

Analysis of Branching in Spring-sown White Lupins (Lupinus albusL.): The Significance of the Number of Axillary Buds

Plant density and sowing date were shown to affect branchingin spring-sown white lupin (Lupinus albusL.), but the responsevaried among environments. The patterns of primary and secondarybranching in the cv. Lublanc were studied as a function of boththe number of axillary buds and the plant growth rate. Fieldexperiments that used a wide range of sowing dates and plantdensities to alter plant architecture were conducted over 5years, and these were supplemented with data from additionalglasshouse and growth cabinet experiments. The number of axillary buds on the main stem or primary branches,which determined the potential number of branches, increasedlinearly with the number of nodes. In situations where all axillarybuds did not produce branches, it was found that the numberof primary and secondary branches produced was related to theplant growth rate at the beginning of branch elongation. Knowledgeof the number of axillary buds improved the analysis of theinteraction between cultural practices and environmental conditionson plant architecture. The variability of branching potentialamong genotypes was discussed. Lupinus albus; branches; axillary buds; growth; sowing date; plant density     

Coupled Diffusion of Peripherally Bound Peptides along the Outer and Inner Membrane Leaflets

Transmembrane signaling implies that peripheral protein binding to one leaflet be detected by the opposite leaflet. Therefore, protein recruitment into preexisting cholesterol and sphingolipid rich platforms may be required. However, no clear molecular picture has evolved about how these rafts in both leaflets are connected. By using planar lipid bilayers, we show that the peripheral binding of a charged molecule (poly-lysine, PLL) is detected at the other side of the bilayer without involvement of raft lipids. The diffusion coefficient, D_P, of PLL differed by a factor of √2 when PLL absorbed to one or to both leaflets of planar membranes. Fluorescence correlation spectroscopy showed that the changes of the lipid diffusion coefficient, D_M, were even more pronounced. Although D_M remained larger than D_P on PLL binding to the first membrane leaflet, D_M dropped to D_P on PLL binding to both leaflets, which indicated that the lipids sandwiched between two PLL molecules had formed a nanodomain. Due to its small area of ∼20 nm² membrane electrostriction or leaflet interaction at bilayer midplane can only make a small contribution to interleaflet coupling. The tendency of the system to maximize the area where the membrane is free to undulate seems to be more important. As a spot with increased bending stiffness, the PLL bound patch in one leaflet attracts a stiffening additive on the other leaflet. That is to say, instead of suppressing undulations in two spots, two opposing PLL molecules migrate along a membrane at matching positions and suppress these undulations in a single spot. The gain in undulation energy is larger than the energy required for the alignment of two small PLL domains in opposite leafs and their coordinated diffusion. We propose that this type of mechanical interaction between two membrane separated ligands generally contributes to transmembrane signaling.     

The Occurrence of Gallionella in Salt Water

A Gallionella sp. is described that lives and freely multiplies in sea water. The habitat of the organism has been thoroughly investigated and the possibility of accidental occurrence has been eliminated. The appearance of the Gallionella sp. described is quite different from the similar iron bacteria occurring in fresh water.     

The Natural Occurrence of Ethionine in Bacteria

Two unknown radioactive areas appeared after radioautography and two dimensional paper chromatography of culture medium in which Escherichia coli was grown. These materials were studied by paper chromatography and paper electrophoresis of several derivatives and identified as ethionine and ethionine sulfone, the latter an artifact. Chromatographic coincidence of the unknowns and their derivatives with authentic materials establishes the identification. Ethionine was found in cellular extracts and in the growth media of Escherichia coli, Bacillus megaterium, Pseudomonas aeruginosa, and Aerobacter aerogenes but not in Scenedesmus, Saccharomyces cerevisiae, or bovine lymphosarcoma cells. Ethionine was synthesized by resting E. coli cultures from radioactive sulfate and from radioactive methionine. Growing cells labeled ethionine within 1 minute after addition of radioactive sulfate to cultures. Levels of radioactivity in ethionine increased with time. No incorporation of this amino acid could be detected in the cellular proteins formed under the conditions of this study.