Modern methods of plant analysis
01 Jan 1964-
About: The article was published on 1964-01-01 and is currently open access. It has received 1991 citations till now.
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TL;DR: A method is described for the determination of LHb in legume root nodule tissue and it is shown that the procedure requires a minimum of specialized equipment and reagents, and is rapid and reproducible.
115 citations
TL;DR: Evidence from litter bag experiments carried out in terrestrial, freshwater and estuarine environments indicates that as much as 30% of the nitrogen content of aged detritus may exist in the form of non-protein nitrogen compounds, which may not be easily digested and assimilated by many detritivores.
Abstract: The nitrogen increase which often accompanies the initial stages of vascular plant decomposition cannot be attributed solely to an increase in microbial protein. Evidence from litter bag experiments carried out in terrestrial, freshwater and estuarine environments indicates that as much as 30% of the nitrogen content of aged detritus may exist in the form of non-protein nitrogen compounds. Possible sources of these compounds include: (1) amino sugars such as glucosamine and chitin, (2) complexes such as phenol-protein, protein-lignin or protein-chitin, (3) complexes of inorganic clays and amino groups, and (4) nitrogen containing humic acids. Chitin, presumably originating from fungal cell walls was shown to constitute from 25 to 50% of the non-protein nitrogen contained in detritus which had decomposed under aerobic conditions. It is suggested that these non-protein nitrogen containing compounds, because of their resistance to chemical degradation, may not be easily digested and assimilated by many detritivores. This, in turn, may raise questions concerning the usefulness of detrital C/N ratios as food value indicators.
115 citations
TL;DR: Rapid AMF colonization enhanced physiological adjustments, which helped plantlets recover rapidly during acclimatization and obtain greater growth during post-acclimatization.
115 citations
TL;DR: This chapter reviews the basic principles of the techniques used for intracellular pH measurement in the main cell compartments—namely, cytoplasm and vacuole and the technical improvements that have been brought about since the previously published reviews are described in the chapter.
Abstract: Publisher Summary This chapter reviews the basic principles of the techniques used for intracellular pH measurement in the main cell compartments—namely, cytoplasm and vacuole Alongwith being both substrate and product in numerous metabolic reactions, protons fulfill the regulatory role of coordinating the activities of enzyme-catalyzed pathways, membrane transport, and other regulators The protons connect cellular compartments and also play important roles in intercellular traffic The sudden pH shifts may impose critical loads on the cells The technical improvements that have been brought about since the previously published reviews are described in the chapter The technique involves the extraction of cell sap and the measurement of its pH with a glass electrode It is used for various types of plant materials The principle of this technique is based on three requirements: the probe molecule is metabolically inert, only the uncharged form is membrane permeant, and the probe is not to change the pH of the respective compartment The distribution of protons within a plant cell appears as a critical element of cell organization and function
115 citations
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References
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01 Jan 1963
TL;DR: In this article, a physiologischer Vorgang auf eine enzymatische Wirkung zuruckgefuhrt werden (vgl. S. 301), besteht die folgende Aufgabe darin, Naheres uber die Eigenschaften des beteiligten Enzyms zu ermitteln.
Abstract: Kann ein physiologischer Vorgang auf eine enzymatische Wirkung zuruckgefuhrt werden (vgl. S. 301), so besteht die folgende Aufgabe darin, Naheres uber die Eigenschaften des beteiligten Enzyms zu ermitteln. Hierzu gehoren die Bestimmung der Reaktions- und Substratspezifitat sowie die Ermittlung der Bedingungen, unter denen eine optimale Wirkung des Enzyms gegeben ist. Wesentlich zur Charakterisierung ist ferner die Untersuchung der Stabilitat des Enzyms und dabei insbesondere die Feststellung, ob es sich um ein Ferment handelt, das zur vollen Aktivitat dialysable Cofaktoren benotigt. Falls diese Frage bejaht wird, ist auch die Bestimmung der unerlaslichen Cofaktoren anzuschliesen. Uberdies bietet auch der Nachweis der Lokalisation des Enzyms in der Zelle (oder im Zellverband) eine entscheidende Moglichkeit zur Charakterisierung des Fermentes. Hinzu kommt schlieslich noch die Untersuchung der Wirkung einzelner Inhibitoren1 auf das Enzym, die zu weitgehender Klarung des Reaktionsmechanismus beitragen kann und eine Abgrenzung der Eigenschaften des untersuchten Fermentes gegenuber ahnlichen Enzymen erlaubt.
2 citations
01 Jan 1962
TL;DR: Optical rotation has been found to be one of the most convenient methods of following the denaturation of proteins and rotatory dispersion is capable of providing information on the folding of the polypeptide chain in proteins and the changes accompanying denaturation.
Abstract: Optical rotation has been found to be one of the most convenient methods of following the denaturation of proteins. Generally speaking denaturation can be defined as a process or sequence of processes in which the spatial arrangement of the polypeptide chains within the molecule is changed from that typical of the native protein to a more disordered arrangement (Kauzmann 1959). The terms “configuration”, “conformation” and “state of folding” are widely used for spatial arrangement. It is probably best to follow the suggestion of Blout (1960) and restrict the use of “configuration” to its original sense, i.e. the spatial arrangement around an asymmetric carbon atom, and to use “conformation” for the shape of the molecule in its entirety. The properties discussed in the previous Chapter i.e., viscosity, diffusion, sedimentation, and light scattering — can all furnish information on the overall shape of proteins or other macromolecules and changes in this shape with environment. Thus Doty, Bradbury and Holtzer (1956) were able to show using these methods, together with streaming birefringence, that poly-γ-benzyl-L-glutamate could exist in two conformations, the α-helix and the solvated randomly coiled form, depending on the solvent. The change from α-helix to random coil was accompanied by marked changes in the optical rotatory properties of the polypeptides. It is to be expected that an α-helical structure should contribute to the rotatory power of a polypeptide since helices are asymmetric and not superimposable on their mirror images. The work on polypeptides has shown that rotatory dispersion is capable of providing information on the folding of the polypeptide chain in proteins and the changes accompanying denaturation.
1 citations