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171.
172.
Ultrastructural and physiological changes in root cells of Sorghum plants (Sorghum bicolor S. sudanensis cv. Sweet Sioux) induced by NaCl 总被引:1,自引:0,他引:1
The xerophytic, but salt-sensitive Sorghum cultivar SweetSioux is known as an ion excluder with a high K/Na selectivityat the plasmalemma and tonoplast of epidermal root cells. Theaim of this study is the correlation of salt-effected changesin physiological parameters with structural and ultrastructuralchanges in root cells. The investigation was carried out withroot cells because these cells are most directly exposed tothe growth medium. Sorghum bicolor S. sudanensis cv. Sweet Sioux plants weregrown under steady-state conditions on nutrient solutions withor without 40 mol m3 NaCl. Sorghum sustained this treatmentbut showed several salt-induced structural and physiologicalchanges which were studied in various cell types of the roottip. (1) NaCl salinity led to a shorter growth region and to salt-inducedalterations in the chemical and physical properties of the cellwalls in the root tips. (2) Salt treatment also increased the membrane surface in rootcells: root cells showed an increase in the quantity of vesiclesin the epidermis and in the middle cortex cells. Additionally,some of the epidermis cells of salt-treated plants revealeda characteristic build-up of transfer cells, suggesting an increasein membrane surfaces to increase the uptake and storage of substances. (3) The number of mitochondria increased in the epidermal andin the cortex cells after salt stress thus indicating an additionalsupply of energy for osmotic adaptation and for selective uptakeand transport processes. (4) In the epidermal cytoplasm NaCl stress led to a significantdecrease of the P, K, Ca, and S concentrations accompanied byan increase of Na concentration. Electron micrographs show anincrease in electron optical contrast within the cytosol andin the matrix of the mitochondria. These results are discussedwith regard to the possibility of influence on the part of metabolicfunctions. (5) The NaCl concentrations were seen to increase and the Kconcentrations to decrease during salt stress in the vacuolesof the epidermis and cortex cells. The salt-induced increasein vacuolar NaCl concentrations of epidermis and cortex cellsare in the region 2 cm behind the root tip, which is sufficientfor an osmotic balance towards the growth medium. Additionalsolutes are necessary 0.5 mm behind the root tip to facilitateosmotic adaptation. The results show ultrastructural changes caused by an Na-avoidingmechanism characterized by a high level of energy consumption.The exclusion of Na from the symplast seems to lead additionallyto a decrease in cytoplasmic concentrations of such essentialelements as Mg, P, S, and Ca and is thus responsible directly(via energy supply in mitochondria, homeostasis, selectivityof K over Na) or indirectly (via enzyme conformation, cytoplasmichydration) for the ultra-structural degradation indicated. Thesalinity-induced multiplicity of structural and functional changeswithin cell compartments constitutes a group of indicators forthe limited NaCl tolerance of Sorghum. Key words: Sorghum bicolor S. sudanensis, ultrastructure, salt tolerance, NaCl, Ca-deficiency 相似文献
173.
174.
Hans-Werner Nolte 《Zoomorphology》1937,33(1):165-200
Ohne ZusammenfassungDissertation der Philosophischen Fakultät der Universität Leipzig. 相似文献
175.
176.
J. Christian Pitt Jürgen Lindemeier Hans-Werner Habbes Rüdiger W. Veh 《Histochemistry and cell biology》1998,110(3):311-322
Haptenylation of primary antibodies is a useful technique for multiple purposes. It is a technically straightforward procedure,
as many haptens are available as N-hydroxysuccinimide esters or isothiocyanates. Unfortunately, the hapten group may become covalently attached to or close
to the combining site of antibodies, lectins, or other ligand-binding proteins during the process of haptenylation. Thus,
the interaction of the corresponding protein with its ligand may become severely hampered. To overcome this restriction, we
developed a novel procedure for the haptenylation of polyclonal antibodies that combines purification and haptenylation. Haptenylation
during adsorption to the affinity matrix combines two advantages: the antigen binding site is protected and the labeling procedure
becomes most convenient, as overlabeled proteins and unreacted haptens are easily removed by simple washing. Haptenylation
during adsorption to the affinity matrix is a two-phase reaction, which requires different conditions to the conventional
procedure. To obtain such optimal conditions, stabilities and reactivities of N-hydroxysuccinimide esters and isothiocyanate groups were investigated with a newly developed assay. Based on this information,
antibodies against two recently described calcium-binding proteins, NCS-1 and NVP-3, were biotinylated or digoxigenylated.
The haptenylated antibodies were successfully applied for biochemical determination and simultaneous immunoenzymatic double
labeling of the two proteins.
Accepted: 9 March 1998 相似文献