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  • 1
    Electronic Resource
    Electronic Resource
    Enhancement of saponificiation rates in aqueous dipolar solvents. Hydroxide ion solvation vs. transition state solvation (1972)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 94 (1972), S. 71-75 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00756a013
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  • 2
    Electronic Resource
    Electronic Resource
    Phytophotodermatitis induced by Ruta chalepensis L. (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 12 (1985), S. 0 
    Details
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0536.1985.tb01121.x
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  • 3
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    Who Brings the Songs (1982)
    Middlebury, Vt. : Periodicals Archive Online (PAO)
    New England review. 4:4 (1982:Summer) 557 
    Details
    ISSN: 1053-1297
    Topics: History
    Notes: poem
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:g063-1982-004-04-000016
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  • 4
    Electronic Resource
    Electronic Resource
    Competition between two desert varieties of Medicago laciniata (L.) Mill. under controlled conditions (1976)
    Springer
    Oecologia 22 (1976), S. 321-339 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two varieties of Medicago laciniata common in the Negev desert of Israel reveal a distinct pattern of distribution within two different plant communities: M. laciniata var. laciniata occupies northern slopes and wadi beds within the association of Artemisia herba-alba, and M. laciniata var. brachyacantha occupies more arid southern slopes within the Zygophylletum dumosi association. Recent field trials have shown that interaction within the plant community restricts distribution of the two varieties, particularly on the northorn slopes. Using the de Wit model on competition, an attempt was made to determine whether the distribution found in nature can be explained on the basis of competition for space. Intervariety competition was measured under controlled conditions in a phytotron under two water regimes. It was found that under both “wet” and “dry” conditions, the two varieties utilize the same space (RYT=1) and similar quantities of water, and both produce similar amounts of dry matter. According to the total dry matter, the varieties have about the same competitive ability under wet as well as under dry conditions. However, under the dry treatment the relative crowding coefficient, based on seed yield, is very different from one: k lb〉2. The relative reproductive rate αlb 〈 1, found under both water regimes, indicates that var. brachyacantha will replace var. laciniata through competition for the same space. This is not in accordance with the observations that var. brachyacantha is absent in the less arid northern slope. A possible explanation is discussed. Reciprocal thinning of the one variety from various mixtures grown under the “dry” regime, when followed by irrigation to field capacity, sharply increases the consumption of water by the plants left, proportional to the number of plants removed. This does not occur in cultures grown under the “wet” regime. It is suggested that such competition for water under optimal water conditions may be due to the occurrence of associations of roots. The possible formation of root associations and its ecological significance of their effect on water consumption are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345311
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  • 5
    Electronic Resource
    Electronic Resource
    Water response of the hygrochastic skeletons of the true rose of Jericho (Anastatica hierochuntica L.) (1978)
    Springer
    Oecologia 32 (1978), S. 289-301 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hygrochastic apparatus in Anastatica hierochuntica was investigated from the standpoint of morphology of the skeleton and fruit and its contribution to the regulation of seed dispersal in accordance with the water conditions. Water absorption by the dry skeletons upon shoot immersion under laboratory conditions is a rapid process requiring only a few minutes. It is followed by a slow opening of the curled branches of the skeleton. Maximal opening is attained by the saturated skeletons in approximately 2h. Absorption of water and subsequent opening occur also when only the main root of the skeleton is immersed in water. The process was duplicated also by intact skeletons irrigated in situ. Skeletons closure in response to evaporation is initially slow, noticable curling of the branches obtained only after 60% of the water is lost from the saturated skeletons. Opening of the skeleton exposes most of the fruits to the force of falling raindrops. The fact that no spontaneous opening of fruits occurred under most laboratory procedures of skeleton immersion suggests that in nature two successive processes occur: the skeletons must first uncurl-hygrochasticly so that raindrops can impinge forcefully on the appendages of the fruit valves and thus cause seed release by ombrohydrochory. Under adequate rainfall, the first fruits to open are those at the outer infructescences; heavier rainfall will release seeds from the upper fruits of the inner infructescences, and later, from fruits at their bases. The force that binds the valves of the fruits to the septa is variable, its strength correlated with different structure of the fruist at different positions on the skeleton. This ensures a rate of seed release commensurate with the rainfall, and secures at least a minimum of water for the first seeds. The heterogeneity of skeleton populations insofar as age of the plants is concerned, further ensures that seed dispersal in a given area will be proportional to the amount of rainfall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345108
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  • 6
    Electronic Resource
    Electronic Resource
    Drought tolerance of germinating seeds and young seedlings of Anastatica hierochuntica L. (1981)
    Springer
    Oecologia 51 (1981), S. 400-403 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Drought tolerance of germinating seeds and young seedlings of Anastatica hierochuntica L. was studied under controlled conditions. When seeds at various stages of germination were air-dried, or alternatively were desiccated over CaCl2 to the same or a lower water level than in the air-dried seeds, and after various periods of storage were rewetted, they readily continued germination or growth. Similarly, 60% of dried young seedlings with rootlets 4–6 mm long that had been dehydrated for one week, renewed their growth 8 h after wetting, their shrivelled, dried rootlets imbibing water. Recovery was adversely affected by both longer periods of germination prior to the dehydration, or by the longer duration of storage of the redried seeds/seedlings. The higher rate of dehydration also reduced recovery. It is argued that despite this tolerance of seedlings to drought, the Rose of Jericho cannot be considered a resurrection plant. Compared with other desert annuals, this behavior is specific for Anastatica. However, it may occur also in other annual species of populations sequestered within the driest of desert habitats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00540912
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  • 7
    Electronic Resource
    Electronic Resource
    Standardized varimax descriptors of event related potentials: Basic considerations (1993)
    Springer
    Brain topography 6 (1993), S. 143-162 
    Details
    ISSN: 1573-6792
    Keywords: Factor analysis ; Z-score ; Varimax ; ERP descriptors ; PCVA ; Discriminant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This paper describes a set of proposed standardized quantitative descriptors of event-related potentials, based upon principal component varimax analysis (PCVA). No claim is made that these mathematical descriptors correspond to discrete neurophysiological processes which generate the ERP. However, adoption and prospective evaluation of such a set of precise, standardized descriptors of the quantitative ERP may eventually result in advances like those which resulted from adoption of equally arbitrary standardized descriptors for QEEG. PCVA was performed on data from normal subjects and from groups of patients with a wide variety of psychiatric disorders (“Abnormals”). This yielded two sets of factor waveshapes, Normal and Abnormal, which were closely similar. Reconstruction of the normal and abnormal ERP data with either set of factors yielded almost identical allocation of variance. These results gave acceptable reassurance that factors derived from normal population could reasonably be used to describe ERP waveshapes from patients. The ERPs at each electrode of the 10/20 System in a “training group” of normal subjects were then reconstructed. The resulting distributions of factor scores were transformed to achieve Gaussianity. Mean values and standard deviations were obtained for the normative distribution of each factor score, the root mean square deviation, the residual and the absolute ERP power at each electrode. Individual ERPs could then be reconstructed with the normal factors, and the resulting factor scores rescaled to “probability of abnormal morphology” by Z-transformation. Statistical probability maps could be generated by using a color scale in standard deviation units. These methods were used to evaluate visual and auditory ERPs from an independent normal “test group” and the patients in the Abnormal sample. High specificity and sensitivity were obtained for many factor Z-scores. Multiple discriminant functions were constructed which separated normal from abnormal patients with high, replicable accuracy. Further development and testing of these descriptors may make them clinically useful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01191080
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  • 8
    Electronic Resource
    Electronic Resource
    The allelopathic potential ofCoridothymus capitatus L. (Labiatae). Preliminary studies on the roles of the shrub in the inhibition of annuals germination and/or to promote allelopathically active actinomycetes (1987)
    Springer
    Plant and soil 98 (1987), S. 53-66 
    Details
    ISSN: 1573-5036
    Keywords: Actinomycetes ; Allelopathy ; Aromatic shrubs ; Coridothymus capitatus ; Essential oils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Suppression of annuals at various intensities was observed around some shrubs ofCoridothymus capitatus growing on kurkar formation in the coastal hills of Israel. The phenomenon was clearly observed as annuals-free belts of 15–20 cm around ‘aggressive’ shrubs. Quantitatively, density of annuals decreased by 16 fold in the annual-free belts as compared to a distance of 60–80 cm from the canopies of the shrubs. Their dry matter was decreased by 5.4 fold around the shrubs. Suppression rate of emergence of planted seeds of annuals (Plantago psyllium andErucaria hispanica) early in the season was 45% higher around ‘aggressive’C. capitatus than that around ‘non-aggressive’ ones. In the laboratory, seed germination of the annuals was strongly suppressed by diffusates and volatiles from shoots, as well as from their water extracts and their essential oils. Incubation of fresh shoots ofC. capitatus in soil collected from around ‘non-aggressive’ shrubs, for 7 days, increased population levels of actinomycetes by 9.6 fold and by 36.7 fold when soil was collected from around ‘aggressive’ shrubs. Isolates of some soil-borne actinomycetes inhibited germination of the test plantsLactuca sativa andAnastatica hierochuntica on agar plates (4–98%). The preliminary results indicate a possible synergistic inhibitory effect induced by essential oils of the aromatic shrub and the phytototic activity of actinomycetes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02381727
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of Exogenously Applied L-Tryptophan on Allelochemical Activity of Plant-Growth-Promoting Rhizobacteria (PGPR) (2000)
    Springer
    Journal of chemical ecology 26 (2000), S. 343-349 
    Details
    ISSN: 1573-1561
    Keywords: allelochemical ; indole-3-acetic acid ; L-tryptophan ; lettuce ; Lactuca sativa ; plant-growth-promoting rhizobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effect of L-tryptophan on root elongation of lettuce seedlings (Lactuca sativa), as well as on allelochemical activity of three species of root growth promoting rhizobacteria (PGPR), was studied under controlled axenic conditions. L-Tryptophan exhibited an hormonelike effect, promoting root elongation of lettuce seedlings at 10−5 and 10−3 mM by ca. 20%, but at 10 mM, root elongation was inhibited by ca. 52% compared to the control (L-tryptophan-free). Comamonas acidovorans 26, Agrobacterium sp., and Alcaligenes piechaudii promoted root elongation of lettuce seedlings by 15, 30, and 44%, respectively. When 10 mM L-tryptophan was applied, Agrobacterium sp. and A. piechaudii inhibited root elongation by 57.6 and 63.5%, respectively. However, at the same concentration of L-tryptophan, C. acidovorans 26 promoted root growth. It is suggested that L-tryptophan reverted root growth promotion through enhancing the secretion of indole-3-acetic acid by the rhizobacteria. L-Tryptophan may have both a direct effect on root growth and an indirect effect through affecting activity of root growth-mediating bacteria. Since the growth of C. acidovorans 26 was exclusively inhibited by L-tryptophan (10 mM), it is conjectured that reduced population of this bacterium could not generate IAA at a level sufficient to inhibit root elongation. Despite the mild root growth promoting effect of C. acidovorans 26, its consistent root growth promotion, perhaps justifies further experimentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005449119884
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  • 10
    Electronic Resource
    Electronic Resource
    Is IAA the Major Root Growth Factor Secreted from Plant-Growth-Mediating Bacteria? (1999)
    Springer
    Journal of chemical ecology 25 (1999), S. 2397-2406 
    Details
    ISSN: 1573-1561
    Keywords: Phytotoxicity ; deleterious rhizobacteria ; indole-3-acetic acid ; lettuce ; Lactuca sativa ; plant-growth-promoting rhizobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The phytotoxic or promoting effect of bacterial secretions on root growth of young lettuce seedlings (Lactuca sativa) was measured under axenic conditions. It was assumed that the inhibitory or promoting effects of either deleterious rhizobacteria (DRB) or of plant growth promoting rhizobacteria (PGPR) were auxin mediated. To avoid measurements of either parasitism or competition, seedlings were placed adjacent to bacterial colonies, with no contact between the organisms. Auxin excretion rate, evaluated by thin-layer chromatography (TLC) combined with Salkowski's reagent, indicated that all bacteria examined produced and released indole-3-acetic acid (IAA). High levels of IAA (76.6 μM) were excreted by four DRB (Micrococcus luteus, Streptoverticillium sp., Pseudomonas putida, and Gluconobacter sp.) during 84 hr of incubation. High concentrations of IAA released by DRB accounted for the suppression of root growth. Other unidentified fractions in the eluates of DRB also inhibited root elongation, but to a lesser extent. Like DRB, four isolates of PGPR (Agrobacterium sp., Alcaligenes piechaudii, and two different strains of Comamonas acidovorans) secreted IAA, but at lower levels (16.4 μM during a similar period of incubation). PGPR secreted growth promoting substances other than IAA, and these are now being investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020890311499
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