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: It was concluded that treatment of moist-chilling for 3 weeks or 1 week moist- chilling followed by 250 ppm GA 3 is recommended for promoting the germination process of loquat seeds and improving growth characteristics of the subsequent seedlings.
41 citations
01 Jan 2007
TL;DR: In this paper, the combination of either Rhizobium, Nitrobein or 25 RHZobium + N itrobein with 0, 1 5, 3 0 or 4 5 Kg P O /faddan on sandy soils was investigated.
Abstract: The co incident application of biofertilizer is frequently recommended firstly for i mproving biological, physical and che mical properties of soil and s econdly to get clean agricultural products free of undesirable high do ses of heavy metals and other pollutant th rough reducing t he d oses of macro chemical fertilizers. Two field exper iments were c onducted at the Agricultural Research Station, National Research Centre, El-Naubaria Provi nce, El Behara G overnorate, Egypt during the two s uccessive winter seasons 2005-06 and 2006- 07 t o i nvestigate the combination of either Rhizobium, Nitrobein or 25 Rhizobium + Nitrobein a ssociated with zero, 1 5, 3 0 or 4 5 Kg P O /faddan on quality a nd quantity yi eld of faba b ean in cul tivated sandy soils. The res ults indicated that increasing pho sphorous levels from zero 25 to 45 kg P O /faddan in combination with Rhizobium, Nitrobein or Rhizobium + N itrobein increased significantly the m ost of studied characters compared to control treatment. Application of phosphorous 25 fertilizer with 30 or 45 kg P O /faddan ass ociated with R hizobium + Nitrobein m ixed inoculums gave the highest va lue of t he mot stud ied parameters i.e., l eaves a nd stems d ry w eight at 60 and 90 DAS, yi eld and i ts components and N PK contents in seeds and s traw and N PK uptake. The combined of 30 or 45 25 kg P O / faddan ass ociated with R hizobium + Nitrobein m ixed inoculums could be applied to get high quantity and quality y ield of faba b ean in cultivated sandy s oils.
41 citations
TL;DR: The results suggest that R-RNA methylating enzymes are bound to particles and that the methylation of R- RNA is a step in the biosynthesis of ribosomes.
41 citations
TL;DR: It is concluded that chronic ozone exposure leads to an inhibition of sucrose synthesis and favours sucrose degradation, and the effect is modulated by the nutrient status of the plants, indicating higher O3 tolerance in HF plants.
Abstract: summary
Birch cuttings (Betula pendula Roth) were grown in a sand-culture system with two concentrations (0.05, HF and 0.005%, LF) of fertilizer containing macronutrients and micronutrients, and were exposed to 90/40 nl 1−1 O3(day/night) and < 3 nl 1−1 O3 (control) for one growing season in the field fumigation chambers at Birmensdorf (Switzerland). Leaves of different ages were analysed for gas exchange, contents of chlorophyll, protein, and for metabolites as well as enzyme activities of carbohydrate metabolism.
Ozone reduced net photosynthesis and chlorophyll contents in mature leaves of both fertilization treatments, whereas that of protein was only reduced in high-fertilized plants (HF). However, net photosynthesis, chlorophyll, and protein increased in young leaves of low-fertilized plants (LF). The effects of ozone on enzyme activities of carbohydrate metabolism were most pronounced in leaves of LF plants. Specific activities of the sucrose-cleaving enzymes, sucrose synthase and alkaline invertase, were induced, whereas acid invertase was unchanged. Extractable activity of sucrose phosphate synthase, which is a key enzyme of sucrose synthesis, was reduced. Levels of fructose 2,6-bisphosphate, an inhibitor of sucrose synthesis, were increased in leaves of O3/LF plants, but reduced in O3/HF plants. In addition, activities of enzymes involved in starch metabolism, ADP-glucose pyrophosphorylase and starch phosphorylase, were lowered in ozone-treated samples and the ratio of ATP: ADP was increased.
It is concluded that chronic ozone exposure leads to an inhibition of sucrose synthesis and favours sucrose degradation. This effect is modulated by the nutrient status of the plants, indicating higher O3 tolerance in HF plants. Furthermore, as the metabolic responses in the ozone-treated samples resemble very closely those observed under end-product inhibition of photosynthesis, we assume that the O3 effect is mainly due to reduced photosynthate export.
41 citations
TL;DR: The results suggest that the cell wall of B. cinerea undergoes significant modifications during growth, possibly becoming more extensively covalently cross-linked, as a result of aging of mycelia or in response to decreasing nutrient supply or as a consequence of increasing culture density.
41 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