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
More filters
TL;DR: Differences in precocity among rootstocks became evident, PADAC 01-47 being the most efficient rootstock for the first bearing years and the fruit quality traits were also significantly affected by rootstocks.
39 citations
TL;DR: The biomass, forest floor biomass, tree litter fall, NPP, and NPP of trees and shrubs increased with increasing age of the forest stand, whereas the dry matter and herb NPP decreased significantly (P < 0.001).
39 citations
TL;DR: Results obtained using the inhibitor of xanthine oxidase, allopurinol, are consistent with the origin of ureides via purine degradation but alternative pathways cannot be discounted.
Abstract: The distribution of ureide-N was studied throughout vegetative and reproductive growth of non-nodulated Phaseolus vulgaris L. (bushbean) grown in nitrate nutrient solution. Largest increases in ureide-N per plant were correlated with flowering and early pod formation and with seed filling. Highest amounts of ureides per organ were measured in stems and axillary trifoliates. Highest concentrations (μmol ureide-N g−1 fr. wt.) were measured in young developing organs and stems. Seeds did not accumulate ureides until the ureide content of pods had reached a maximum.
Results obtained using the inhibitor of xanthine oxidase, allopurinol, are consistent with the origin of ureides via purine degradation but alternative pathways cannot be discounted.
Leaves and stems were shown to have the ability to degrade allantoate via an enzymic process.
38 citations
38 citations
TL;DR: The two chrysomonads, Coccolithus huxleyi and a Hymenomonas sp.
Abstract: SUMMARY: The two chrysomonads, Coccolithus huxleyi and a Hymenomonas sp., contained chlorophylls a and c, carotene and fucoxanthin, and a number of minor xanthophylls. Coccolithus huxleyi was rich in chlorophyll c and had a chlorophyll a:c ratio of 1.5:1.0; in Hymenomonas the ratio was 5:1. Incubation of broken-cell preparations at high light intensities resulted in the decomposition of chlorophyll a, whereas chlorophyll c was stable under these conditions. This photochemical bleaching of chlorophyll a shifted the spectrum from 678 to 674 mμ with a difference spectrum showing a maximum at 680 mμ. Maximum photosynthetic rates of 150-200 μmoles CO2/mg. chlorophyll a+c/hr were reached in 10-day cultures. Maximum populations of 106 organisms/ml. for Hymenomonas and 107 for C. huxleyi were reached in about 14 days. Hymenomonas grew best at light intensities of 800 ft.c. or higher, whereas growth of C. huxleyi was independent of light intensity above 60 ft.c. Maximum photosynthetic rates were obtained at a light intensity of 3500 ft.c.
38 citations
References
More filters
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