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151.
REINDERS J. E. A.; AS H. VAN; SCHAAFSMA T. J.; SHERIFF D. W. 《Journal of experimental botany》1988,39(9):1211-1220
Nuclear magnetic resonance (NMR) was used to investigate theeffects of changes in root temperature, of changes in the areaof root in contact with culture solution and of day/night rhythmon the water balance of a cucumber and a gherkin plant. Resultsare discussed in terms of water potential, flow rate and resistanceusing a previously presented model of water balance. As longas water uptake alone is varied, flow rate and water content(or potential) will change in the same direction. In contrast,from that model it is predicted that changes in transpirationwill affect flow rate and water content in opposite ways. Anexperimental verification of this prediction was given in theprevious paper. Results obtained by the NMR method are comparedto those determined using a dendrometer. The results demonstratethat the NMR method is a valuable tool to study plant waterbalance and that it can serve as a technique for discriminatingbetween changes in plant water balance that are due to changesin water uptake by roots and those due to changes in transpiration. Key words: Water balance model, Cucumis satious L., flow, water content, NMR, water balance measurement 相似文献
152.
153.
C. Zervos 《Journal of theoretical biology》1975,50(2):253-258
It has been proposed (Johnston & Diven, 1969a) that it is valid to use semilogarithmic (first-order) plots of the extent of reaction versus time for graphic determination of initial velocities of enzyme-catalyzed reactions. This proposition suggests the assumption that the initial velocity error expected to be introduced by the proposed procedure is smaller than or comparable to the error introduced by the customary graphic procedure. The latter is based on the assumption that the progress curves of enzyme-catalyzed reactions have an initial linear segment of sufficient duration to permit accurate determination of slope. The validity of the procedure proposed by Johnston and Diven is examined in this report. It is concluded that the procedure is applicable to a very small class of enzyme-catalyzed reactions and only under certain experimental conditions. 相似文献
154.
M Morgan Conn Joe Kappock Dale Drueckhammer Richard Cammack Dennis Hall Tony Cass Jon D Stewart Graham RL Cousins Jeremy KM Sanders Sabine Flitsch Philip AS Lowden Richard Newman 《Current opinion in chemical biology》1999,3(6):631
A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in chemical biology. 相似文献
155.
156.
S. Zervos 《New Zealand journal of zoology.》2013,40(2):155-164
Abstract A monotypic new genus, Bispiculum, is erected for B. inaequale n.sp. from the haemocoel of Platypus apicalis, P. caviceps, and P. gracilis, ambrosia beetles indigenous to New Zealand. B. inaequale is characterised by its possession of a pair of spicules and three rows of anal papillae in the male, and ‘escape-form’ juveniles. This is the first record of a tetradonematid in New Zealand, and the first of a tetradonematid from the Curculionidae. All stages are described, and the life history is discussed. The diagnosis of the Tetradonematidae is emended, the family is reviewed, and a key to species is provided. 相似文献
157.
F. R. SCARANO FLS H. M. DUARTE G. RÔÇAS S. M. B. BARRETO E. F. AMADO F. REINERT T. WENDT A. MANTOVANI H. R. P. LIMA C. F. BARROS 《Botanical journal of the Linnean Society. Linnean Society of London》2002,140(4):391-401
The clonal tank-bromeliad Aechmea bromeliifolia (Rudge) Baker was found in four different habitats in a restinga (vegetation mosaic on sandy coastal plains), of south-eastern Brazil. These habitats (swamp forest, dry forest, dry shrubland and herbaceous marsh) lie within a few hundred metres of each other along a gradient extending inland from the coast, and differ markedly in terms of light and flood regime. We compared ramet morphology, leaf anatomy and physiology, and population parameters to examine the amplitude of trait variation of this widespread species in the studied restinga. This integrated approach allowed us to examine which variation conferred acclimation and which was merely a stress symptom. A . bromeliifolia showed site-specific differences in abundance, distribution, rosette size and shape, leaf anatomical arrangement and photochemical efficiency (potential quantum yield; F v / F m ) during the day. Most of the variation found seemed to be related to the interaction of light and flooding. The lowest number and size of ramets at the exposed, dry shrubland was matched by a marked leaf photoinhibition, which suggested poor acclimation to local levels of light intensity and limited water supply. In the other habitats, the morpho-physiological parameters measured suggested adequate foraging behaviour and site acclimation. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 391-401. 相似文献