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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 Article
TL;DR: Five succulent halophytic species selected during summer from the coastal zo ne along each of A l-Qatif on the Arabian Gulf in Saudi Arabia and south of Safaga on the Red Sea in Egypt tended to accumulate high contents of p hotosynthetic pigments, free amino acids and higher levels of POD activity.
Abstract: Halophytes r esiding i n co astal areas of the semi- arid regions are often subject ed to intense and varying environmental stresses. In order to adapt with non-permissive conditions, they developed growth, physiological and biochemical changes for s urvival that allow t hem to grow in s aline hab itats. Five succulent ha lophytic species w ere selected during summer from the coastal zo ne along each of A l-Qatif on the Arabian Gulf in Saudi Arabia (Site I) and south of Safaga on the Red Sea in Egypt (Site II). These included: Halocnemum strobilaceum, Arthrocnemum macrostachyum, Halopeplis perfoliata, Suaeda vermiculata and Seidlitzia rosmarinus. T heir re sponse to salinity was stu died in both site s in respect t o habitat conditions. The i nvolvement of photosynthetic p igments, ions, free am ino acid, soluble p rotein, soluble sugar and proline,, as well as activities of certain antioxidant enzymes activation in salt tolerance of these h alophytes were i nvestigated. Plants obtained from Site I I were c haracterized by higher values of TWC and RWC concomitantly with hi gh co ntents of photosynthetic p igment fractions (chl.a, chl.b and carotenoids). Results p ointed to a p rominent f eature in the mechanism of the protective adaptive response mechanisms o f ha lophytes. It was o bserved that ha lophytes o f S ite I t ended to retain h igher so luble protein, soluble sugar , proline and total organic o smolytes as well as higher activity levels o f CA T and GR enzymes, w hile the halophytic species o f S ite II tended to accumulate high contents of p hotosynthetic pigments, free amino acids and higher levels of POD activity. It is o f interest to observe t hat the accumulation of total organic osmolytes of most studied halophytes were associated with the increase of succulence ratio attained concurrently with higher values of Cl-, Na+ and SO4œ² determined in each of soil and plants either collected from Site I or s ite II .

44 citations

Journal ArticleDOI
TL;DR: From autolysed cultures of Mucor rouxii, two chitosanases, A and B, were purified to electrophoretic homogeneity and both enzymes showed an endo-splitting type of activity, and the end product of chitOSan degradation contained a mixture of dimer, trimer and higher molecular mass oligomers of glucosamine.
Abstract: From autolysed cultures of Mucor rouxii, two chitosanases, A and B, were purified to electrophoretic homogeneity. Apparent Mr values of 76 000 and 58 000 and pI values of 4.9 and 4.7 were determined for A and B, respectively. Both chitosanases showed a high specificity for chitosan and chitosan derivatives. They had optimum activities at pH 5.0 and at temperatures of 55°C and 50°C for A and B, respectively. Enzyme A was inhibited by acetate ions and enzyme B by high substrate concentration. Both enzymes showed an endo-splitting type of activity, and the end product of chitosan degradation contained a mixture of dimer, trimer and higher molecular mass oligomers of glucosamine. Glucosamine oligosaccharides were poorly hydrolysed by these enzymes. Both enzymes extensively degraded the chitosan extracted from M. rouxii cell walls.

44 citations

Journal ArticleDOI
TL;DR: This research compared the chlorophyll biosynthetic and degradation pathways, pigment-protein complexes, and thylakoid morphology of a mature oval-pointed cecidomyiid gall and the infected leaf of host plant Machilus thunbergii Sieb & Zucc (Lauraceae).
Abstract: This research compared the chlorophyll biosynthetic and degradation pathways, pigment-protein complexes, and thylakoid morphology of a mature oval-pointed cecidomyiid gall and the infected leaf of host plant Machilus thunbergii Sieb & Zucc (Lauraceae). The mature gall always possesses far less photosynthetic pigment than the infected leaf. The content of anthocyanin and tannin of the gall are much higher than in the infected leaf. Both the mole percent of porphyrin and the ratio of pheophytin/chlorophyllide are much different between the gall and infected leaf, suggesting their chlorophyll biosynthetic and degradation pathways are much different. While the infected leaf may take the degradation pathway of chlorophyll®pheophytin®pheophorbide as the major route, the cicedomyiid gall may take chlorophyll®chlorophyllide®pheophorbide as the major route. The infected leaf still possesses the CPI and CPII pigment-protein complexes fractionated by Thornber system, or the A1, AB1, AB2, AB3 pigment-protein complexes fractionated by the MARS system while the mature gall contains only CPII or AB3. Electron microscopy demonstrated that the mature gall has normal grana and thylakoid morphology. It is still unknown whether the unique deficiency of pigment-protein complexes is ubiquitous and how the cecidomyiid insects cause the deficiency of some pigment-protein complexes.

44 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared two approaches to interpret dD of cellulose nitrate in pinon pine needles (Pinus edulis) preserved in packrat middens from central New Mexico, USA.

44 citations

Journal ArticleDOI
TL;DR: 1,3-specific lipase and its mixture with phospholipase A2, and linoleic and linolenic acids were replaced, suggesting an improved oxidative stability of the resulting product and hydrolysis could not be prevented, but it could be regulated by incubation time and by enzyme dosage.
Abstract: Soy lecithin was modified by enzymatic transesterification in a solvent-free system. 1,3-SpecificRhizomucor miehei lipase was found to be efficient in the transesterification with lauric acid and oleic acid, where oleic acid was more incorporated into soy lecithin. Phospholipase A2 incorporated lauric acid hardly at all, but it hydrolyzed lecithin efficiently. The mixture of lipase and phospholipase A2 (1:1, w/w) incorporated lauric acid to the same extent as did 1,3-specific lipase alone at the same total enzyme concentration. The main fatty acids replaced were palmitic and linoleic acids by 1,3-specific lipase and its mixture with phospholipase A2, and linoleic and linolenic acids by phospholipase A2 alone, suggesting an improved oxidative stability of the resulting product. Hydrolysis could not be prevented, but it could be regulated by incubation time and by enzyme dosage. The minimal water content for significant incorporation of lauric acid into lecithin was below 0.5% of the weight of the reaction mixture.

44 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