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Modern methods of plant analysis

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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Citations
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Journal ArticleDOI
TL;DR: By lowering sucrose concentration from 20% to 5 or 10 % and adding polyethylene glycol 4000 in the culture medium, high percentage germination and high tube growth can be achieved in three species of cultivated Brassica.
Abstract: The culture media for the in vitro pollen assay of Brassica species have so far shown good percentage germination, but limited pollen tube growth. It is reported here that by lowering sucrose concentration from 20% to 5 or 10 % and by adding polyethylene glycol 4000 in the culture medium, high percentage germination and high tube growth (10 times that in the standard media) can be achieved in three species of cultivated Brassica. This improved medium should be useful in fundamental and applied studies on the pollen biology of Brassica species.

41 citations

Journal ArticleDOI
TL;DR: The location of the enzymes potentially involved in ammonia assimilation in nitrogen fixing root nodules of Phaseolus vulgaris has been examined by sucrose density gradient separation of the bacteroids from plant organelles and there is little evidence for the presence of significant proportions of the total glutamine synthetase and glutamate synthase activity being present in the bacteriod.

41 citations

Journal ArticleDOI
TL;DR: Chlorophyll accumulation in tuber discs was inhibited by cycloheximide, chloramphenicol, lincomycin, δ-aminolaevulinic acid, benzyladenine, and high concentrations of sodium arsenate and potassium cyanide, but was unaffected by 2,4-D, laevulinics acid and malonic acid.
Abstract: SUMMARY White potato tuber tissues (Solarium tuberosum, vars. King Edward and Craigs Royal), contained carotenoids but did not contain either protochlorophyll or chlorophyll. On illumination of tuber discs, the accumulation of chlorophyll a and chlorophyll b began simultaneously after 19 hours and continued for 3 weeks. This greening process was associated with a synthesis of galactolipids. Light of intensity 750 1× was sufficient to induce maximum greening and to cause greening throughout the disc. Blue light was more effective than orange or green light. Chlorophyll accumulation in tuber discs was inhibited by cycloheximide, chloramphenicol, lincomycin, δ-aminolaevulinic acid, benzyladenine, and high concentrations of sodium arsenate and potassium cyanide. It was unaffected by 2,4-D, laevulinic acid and malonic acid. When green discs were returned to darkness, the total chlorophyll content remained constant over a period of 7 days but the ratio of chlorophyll a to chlorophyll b decreased. These results are discussed in terms of the control mechanisms and differentiation processes involved in the development of chloroplasts from amyloplasts.

41 citations

Book ChapterDOI
01 Jan 1990
TL;DR: In this paper, the isotope content and the ratio of deuterium and hydrogen atoms in a given molecular species, D/H, are not constant on Earth and the original approaches provided by the NMR study of Site-Specc Natural Isotope Fractionation of hydrogen must be seen in this context.
Abstract: The isotope content and in particular the ratio of deuterium and hydrogen atoms in a given molecular species, D/H, are not constant on Earth. On the basis of the overall molecular isotope contents accessible by mass spectrometry techniques, important information has been obtained on biochemical and physiological aspects of biosyntheses under natural conditions. The original approaches provided by the NMR study of Site-Specc Natural Isotope Fractionation of hydrogen must be seen in this context.

41 citations

References
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Book ChapterDOI
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

Book ChapterDOI
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