All nuclei in mesophyll cells of Artemisia marschalliana are located in vacuoles and occupy up to 90% of their volume. The ultrastructural organization of chromatin in nuclei shows different degrees of its decondensat...All nuclei in mesophyll cells of Artemisia marschalliana are located in vacuoles and occupy up to 90% of their volume. The ultrastructural organization of chromatin in nuclei shows different degrees of its decondensation, up to complete separation of DNA from histones. It is possible that the separation of DNA from histones enables Artemisia to grow in soils with high salinity.展开更多
The fixation of leaves of Tanacetum vulgare L. in glutaraldehyde makes it possible to isolate chloroplasts without sacrificing an electron dense substance in the thylakoid lumen. The extraction of lipids from the chlo...The fixation of leaves of Tanacetum vulgare L. in glutaraldehyde makes it possible to isolate chloroplasts without sacrificing an electron dense substance in the thylakoid lumen. The extraction of lipids from the chloroplasts isolated from the leaves preliminarily fixed in glutaraldehyde has demonstrated that glycerolipids (galactolipids and phospholipids) are not manifested in TLC, whereas isoprenoid lipids (chlorophyll, carotenoids) are manifested. Presumably, isoprenoid lipids are not fixed with glutaraldehyde and are extracted from the thylakoid membrane. The ultrastructural control demonstrates that the electron dense substance from the thylakoid lumen is also extracted. It is possible that this substance is of isoprenoid nature.展开更多
The purpose of the work was to assess the combined effect of drought and salinity (50, 100, 200 mМ NaCl) on the meso- and ultrastructure of mesophyll cells of wheat seedlings. Stress development was estimated by a de...The purpose of the work was to assess the combined effect of drought and salinity (50, 100, 200 mМ NaCl) on the meso- and ultrastructure of mesophyll cells of wheat seedlings. Stress development was estimated by a decrease in the relative water content (RWC) and CO2-dependent O2 evolution (An) in leaves. The decrease in the RWC and in An occurred rapidly in the absence of salt in the substrate and slowly in the presence of salt, especially at a treatment of 100 mM NaCl. The resumption of watering led to the recovery of the both parameters in all variants except one with 200 mM NaCl. Structural studies showed that a weak drought stress (RWC 60%) without salinity led to the destruction of cell membranes and hyaloplasm, which did not occur in all salt treatments. By contrast, the ultrastructure of nuclei in weak drought without salinity remained unchanged, whereas in all salt treatments chromatin changed substantially. Heterochromatin underwent a strong condensation followed by the fusion into a united mass with the simultaneous loss of electron density. A strong water stress (RWC 40%) in all variants led to cell destruction and the hydrolysis of cell compounds. Under the drought without salinity, vacuoles disappeared, whereas in salt-treated samples they were retained and filled with organelles being at different degrees of degradation. Cell nuclei under strong drought stress lost their rounded shape, nuclear envelopes were destroyed, and at the end only a finely dispersed substance remained. Thus, under the combined action of drought and salt, there is some critical level of salt concentration in substrate above which the effect of NaCl changes to the adverse, which enhances the action of drought. Among structural components of mesophyll cells, the most sensitive parts to NaCl are nuclei and their chromatin.展开更多
文摘All nuclei in mesophyll cells of Artemisia marschalliana are located in vacuoles and occupy up to 90% of their volume. The ultrastructural organization of chromatin in nuclei shows different degrees of its decondensation, up to complete separation of DNA from histones. It is possible that the separation of DNA from histones enables Artemisia to grow in soils with high salinity.
文摘The fixation of leaves of Tanacetum vulgare L. in glutaraldehyde makes it possible to isolate chloroplasts without sacrificing an electron dense substance in the thylakoid lumen. The extraction of lipids from the chloroplasts isolated from the leaves preliminarily fixed in glutaraldehyde has demonstrated that glycerolipids (galactolipids and phospholipids) are not manifested in TLC, whereas isoprenoid lipids (chlorophyll, carotenoids) are manifested. Presumably, isoprenoid lipids are not fixed with glutaraldehyde and are extracted from the thylakoid membrane. The ultrastructural control demonstrates that the electron dense substance from the thylakoid lumen is also extracted. It is possible that this substance is of isoprenoid nature.
文摘The purpose of the work was to assess the combined effect of drought and salinity (50, 100, 200 mМ NaCl) on the meso- and ultrastructure of mesophyll cells of wheat seedlings. Stress development was estimated by a decrease in the relative water content (RWC) and CO2-dependent O2 evolution (An) in leaves. The decrease in the RWC and in An occurred rapidly in the absence of salt in the substrate and slowly in the presence of salt, especially at a treatment of 100 mM NaCl. The resumption of watering led to the recovery of the both parameters in all variants except one with 200 mM NaCl. Structural studies showed that a weak drought stress (RWC 60%) without salinity led to the destruction of cell membranes and hyaloplasm, which did not occur in all salt treatments. By contrast, the ultrastructure of nuclei in weak drought without salinity remained unchanged, whereas in all salt treatments chromatin changed substantially. Heterochromatin underwent a strong condensation followed by the fusion into a united mass with the simultaneous loss of electron density. A strong water stress (RWC 40%) in all variants led to cell destruction and the hydrolysis of cell compounds. Under the drought without salinity, vacuoles disappeared, whereas in salt-treated samples they were retained and filled with organelles being at different degrees of degradation. Cell nuclei under strong drought stress lost their rounded shape, nuclear envelopes were destroyed, and at the end only a finely dispersed substance remained. Thus, under the combined action of drought and salt, there is some critical level of salt concentration in substrate above which the effect of NaCl changes to the adverse, which enhances the action of drought. Among structural components of mesophyll cells, the most sensitive parts to NaCl are nuclei and their chromatin.
