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.
Citations
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22 Mar 1984
TL;DR: In this paper, Holden et al. developed an equation for the determination of total chlorophyll and individual amounts of chlorophyLLs a and b in extracts from plant tissues, and some of them (e.g. Arnon 1949) have been widely used.
Abstract: Various equations for the determination of total chlorophyll and individual amounts of chlorophylls a and b in extracts from plant tissues exist (see Holden 1976) and some of them (e.g. Arnon 1949) have been widely used. Additional modifications to the equations have also been developed so as to permit an estimate of total carotenoids to be made from the spectrum of the same mixture in di-ethyl ether (Ziegler, Egle 1965; Gaudillere 1974).
358 citations
TL;DR: This chapter focuses on the hemicelluloses of the Gramineae (grasses and cereals), which refers to all of the types of polysaccharide in the Gramineaae, other than celluloses, starches, and fructans.
Abstract: Publisher Summary This chapter focuses on the hemicelluloses of the Gramineae (grasses and cereals). The term “hemicelluloses” is also often extended to include certain carbohydrates in cereal endosperms—namely, non-starch polysaccharides. Hemicellulose refers to all of the types of polysaccharide in the Gramineae, other than celluloses, starches, and fructans. Hemicellulose chemistry has a vocabulary lacking invariant definitions, and insight into the nature of hemicelluloses has been gained by the work not only of chemists and biochemists but of applied scientists having research interests in animal nutrition, brewing, cereals, paper manufacture, and starch production. The chapter also discusses species and various tribes of Gramineae, isolation of hemicellulosimca materials and of pure hemicelluloses, and structural feature in hemicelluloses. The importance of knowledge about the hemicelluloses may be gauged by looking at the abundance of photosynthetically renewable grasses and bearing in mind that, apart from the materials in the seed, one third of their composition is hemicellulose.
357 citations
TL;DR: Mannitol metabolism may play roles in plant responses to both biotic and abiotic stresses, and increased tolerance to salt- and osmotic-stress as a result of mannitol's function as a ‘compatible solute'.
350 citations
TL;DR: In this paper, the effects of short term NaCl stress and recovery on growth, water relations, ionic composition, lipid peroxidation and antioxidants in roots of two rice cultivars differing in salt tolerance were studied.
Abstract: The comparative alterations of short term NaCl stress and recovery on growth, water relations, ionic composition, lipid peroxidation and antioxidants in roots of two rice cultivars differing in salt tolerance were studied. Exposed for 24 h to increasing (50, 100 and 150 mmol l−1) concentrations of NaCl, roots of 12D Oryza sativa L. cv. Lunishree and cv. Begunbitchi decreased in fresh weight, dry weight and relative water content. Increased Na+ and decreased K+ ion were determined at increasing NaCl concentrations. Both peroxide content and lipid peroxidation measured in terms of MDA level increased and the ratio was higher in Begunbitchi compared to Lunishree. Recovered roots showed lower peroxide and MDA content. Ascorbate and glutathione contents increased in the stressed and recovered roots of Lunishree, but decreased in Begunbitchi with increasing NaCl concentrations. Although SOD, CAT and GR activities decreased in the stressed roots, CAT activity also increased in recovered roots of both the cultivars. The POX activity increased in stressed and recovered roots of both Lunishree and Begunbitchi. Higher free radicals scavenging capacity and more efficient protection mechanism of Lunishree against salt stress, as revealed by the lower level of lipid peroxidation and improved plant water status as well as activities of some of the antioxidants, suggest that significant cultivar differences in response to salt stress in rice are closely related to differences in the activities of antioxidants and ion content. Another possible conclusion is that improved tolerance to salt stress may be accomplished by increased capacity of antioxidative system.
349 citations
TL;DR: In this article, a detailed account of investigations on the functioning of the reaction center protein with a number of optical and magnetic resonance spectroscopic techniques is presented, with emphasis on the relation between structure and function.
337 citations
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