Effect of oryzalin on root ultrastructure and respiration in various wheat cultivars subjected to cold hardening

The effect of anti-microtubular herbicide oryzalin (10 μ, 2-4 days) on the root ultrastructure and respiration in two cultivars of winter wheat (Triticum aestivum L.) contrasting in their frost-tolerance was studied during plant cold hardening (3°0C, 3 days). The sensitivity of subcellular structures to oryzalin depended closely on cell metabolic activity and the extent of development of the cortical microtubule (MT) network. Most pronounced oryzalin-induced changes were related to enhanced cell vacuolation and the appearance of some signs of apoptosis (as judged from cytoplasm fragmentation) in some cells. In the root zone examined, cell heterogeneity increased, when, along with normally functioning cells, dramatically damaged and even completely destroyed cells appeared. Simultaneously, the activity of cyanide-resistant nonphosphorylating respiration pathway was activated, especially during cold hardening. In hardened cells, single cortical microtubules appeared in both wheat cultivars; this fact indicates that new cold-resistant subpopulations of MT were resistant to depolymerizing action of oryzalin. © MAIK "Nauka/Interperiodica", 2006

Influence of cytoskeletal agents on the respiratory electron transport pathways in the cells of winter wheat leaves

The effects of actin and tubulin polymerization inhibitors on the respiratory electron transport pathway activities were investigated using abscisic acid (ABA)- and cold-treated winter wheat seedling leaves. In unstressed control plants, cytochalasin B (15 μM) decreased the capacity of the cytochrome pathway, but stimulated the cyanide-resistant pathway, whereas oryzalin (15 μM) produced the opposite effects. Cold hardening (3°C for 7 days) and ABA treatment 30 μM changed the respiratory pattern in a similar manner to cytochalasin B but to lesser effects. This points to cold- and ABA-induced reduction in microfilament sensitivity to these drugs and hence stabilization of actin-dependent processes. In contrast, oryzalin had only weak effects on control samples and its effects were strengthened in the presence of the cytoskeleton-modifying factors. The data suggest that the potential targets for the agent either increase and/or the degree of involvement of microtubules in the respiratory chain regulation, and therefore that the cytoskeleton can modify the functioning of the respiratory electron transport pathways in winter wheat cells. (C) 2000 Academic Press

Effect of Anti-Microtubular Agents on Respiration and Ultrastructural Organization of Wheat Leaf Cells

The effect of anti-microtubular agents oryzalin (15 μM) and colchicine (1 mM) on respiration and fine cellular organization of leaves was studied in wheat (Triticum aestivum L.) seedlings. Unlike oryzalin, colchicine considerably suppressed total respiration and the activities of cytochrome and cyanide-resistant pathways of electron transport, probably due to its rotenone-like effect since the latter was negated by vicasol that shunts the first complex of respiratory chain. Oryzalin-induced changes in the ultrastructure of mitochondria and polysomes corresponding to a decrease in their functional activity were detected. The changes in the shape of mitochondria were observed in the companion cells, whereas the mesophyll organelles did not respond to oryzalin. Disintegration of polysomes induced by oryzalin was detected in the cells of both tissues. Association of microtubules with mitochondria, polysomes, and plasma membrane was detected in situ. These data suggest that the intact cytoskeleton may participate in the spatial organization of energy transformation and protein synthesis machinery of the cells; the fact that the observed changes were tissue-specific points at the functional role of microtubules and/or to the number of targets for the inhibitor

Changes of photosynthesis and carbon metabolism in Typha angustifolia L grown in conditions of nitrate nitrogen overload

Nitrates may induce alterations in NO-signaling system and change photosynthesisin plants. Significant reduction of 14CO2 fixation was noted at concentration of 3.96mM NaNO3 in an aquatic macrophyte (Typha angustifolia L.). Assimilation of 14CO2 seven days after the introduction of nitrates did not differ between control and experimental samples. There were changes in distribution of 14C among products of 4CO2 fixation 4 h after NaNO3 addition, resulting in increased sugar radioactivity in experimental plants. It was suggested that the observed changes may have regulatory importance

Modification of Oligomers and Reinforced Polymeric Composites by Carbon Nanotubes and Ultrasonic

An abridged version of the book chapter is presented in the archive. Full version on the publisher's site: https://link.springer.com/chapter/10.1007/978-3-030-26672-1_3Розглядається широке коло питань щодо розроблених напрямів модифікації епоксидних олігомерів і армованих полімерних композитів на їх основі вуглецевими нанотрубками і ультразвуком. Аналізується перспективність створення гібридних полімерних композитів функціонального призначення.This chapter analyzes the physical (in the form of ultrasound) and chemical modification of liquid polymer media and reinforced polymeric composites. The main emphasis is made on the analysis of ultrasonic cavitation processing as the most effective one for solving one of the main technological problems in the production of nanomodified polymer composites

Respiration and morphology of mitochondria in the crowns of winter wheat plants exposed to low temperatures and cartolin

The respiration and ultrastructure of mitochondria from winter wheat (Triticum aestivum L.) crowns were studied with emphasis on the adaptation of plants to low temperatures during the autumn-winter period under field conditions. Analysis of the separate and combined oxidation of substrates revealed competitive relations between succinate dehydrogenase and malate dehydrogenase - the mutual inhibition of these enzymes. Succinate was the preferable substrate of oxidation compared to malate during autumnal months, but the predominance of succinate oxidation diminished during cold hardening. During cold hardening, mitochondria change their shape, e.g., their cross-sections acquired toroidal, dumbbell-shaped, and other unusual profiles. Presowing treatment of seeds with the growth regulator cartolin raised the morphological heterogeneity of mitochondria, caused their association into reticular structures, induced the "succinate-type" of respiration, and elevated the rate of cyanide-resistant electron flow. All this indicates intense energy metabolism, which promotes metabolic adaptation. Freezing temperatures induced the "disintegration" of complex mitochondrial profiles, degeneration of cristae, clarification of the mitochondrial matrix, and depression of the oxidation rate. At the same time, freezing temperatures led to an increase in the plasmalemma area at the expense of numerous foldings and invaginations, and the induction of endocytosis. It is concluded that compensatory rearrangements of mitochondria and plasmalemma during cell adaptation to low temperatures depend on the degree and duration of cooling

Effect of oryzalin on root ultrastructure and respiration in various wheat cultivars subjected to cold hardening

The effect of anti-microtubular herbicide oryzalin (10 μ, 2-4 days) on the root ultrastructure and respiration in two cultivars of winter wheat (Triticum aestivum L.) contrasting in their frost-tolerance was studied during plant cold hardening (3°0C, 3 days). The sensitivity of subcellular structures to oryzalin depended closely on cell metabolic activity and the extent of development of the cortical microtubule (MT) network. Most pronounced oryzalin-induced changes were related to enhanced cell vacuolation and the appearance of some signs of apoptosis (as judged from cytoplasm fragmentation) in some cells. In the root zone examined, cell heterogeneity increased, when, along with normally functioning cells, dramatically damaged and even completely destroyed cells appeared. Simultaneously, the activity of cyanide-resistant nonphosphorylating respiration pathway was activated, especially during cold hardening. In hardened cells, single cortical microtubules appeared in both wheat cultivars; this fact indicates that new cold-resistant subpopulations of MT were resistant to depolymerizing action of oryzalin. © MAIK "Nauka/Interperiodica", 2006

Effect of oryzalin on root ultrastructure and respiration in various wheat cultivars subjected to cold hardening

The effect of anti-microtubular herbicide oryzalin (10 μ, 2-4 days) on the root ultrastructure and respiration in two cultivars of winter wheat (Triticum aestivum L.) contrasting in their frost-tolerance was studied during plant cold hardening (3°0C, 3 days). The sensitivity of subcellular structures to oryzalin depended closely on cell metabolic activity and the extent of development of the cortical microtubule (MT) network. Most pronounced oryzalin-induced changes were related to enhanced cell vacuolation and the appearance of some signs of apoptosis (as judged from cytoplasm fragmentation) in some cells. In the root zone examined, cell heterogeneity increased, when, along with normally functioning cells, dramatically damaged and even completely destroyed cells appeared. Simultaneously, the activity of cyanide-resistant nonphosphorylating respiration pathway was activated, especially during cold hardening. In hardened cells, single cortical microtubules appeared in both wheat cultivars; this fact indicates that new cold-resistant subpopulations of MT were resistant to depolymerizing action of oryzalin. © MAIK "Nauka/Interperiodica", 2006

Respiration and morphology of mitochondria in the crowns of winter wheat plants exposed to low temperatures and cartolin

The respiration and ultrastructure of mitochondria from winter wheat (Triticum aestivum L.) crowns were studied with emphasis on the adaptation of plants to low temperatures during the autumn-winter period under field conditions. Analysis of the separate and combined oxidation of substrates revealed competitive relations between succinate dehydrogenase and malate dehydrogenase - the mutual inhibition of these enzymes. Succinate was the preferable substrate of oxidation compared to malate during autumnal months, but the predominance of succinate oxidation diminished during cold hardening. During cold hardening, mitochondria change their shape, e.g., their cross-sections acquired toroidal, dumbbell-shaped, and other unusual profiles. Presowing treatment of seeds with the growth regulator cartolin raised the morphological heterogeneity of mitochondria, caused their association into reticular structures, induced the "succinate-type" of respiration, and elevated the rate of cyanide-resistant electron flow. All this indicates intense energy metabolism, which promotes metabolic adaptation. Freezing temperatures induced the "disintegration" of complex mitochondrial profiles, degeneration of cristae, clarification of the mitochondrial matrix, and depression of the oxidation rate. At the same time, freezing temperatures led to an increase in the plasmalemma area at the expense of numerous foldings and invaginations, and the induction of endocytosis. It is concluded that compensatory rearrangements of mitochondria and plasmalemma during cell adaptation to low temperatures depend on the degree and duration of cooling

Effect of oryzalin on root ultrastructure and respiration in various wheat cultivars subjected to cold hardening

The effect of anti-microtubular herbicide oryzalin (10 μ, 2-4 days) on the root ultrastructure and respiration in two cultivars of winter wheat (Triticum aestivum L.) contrasting in their frost-tolerance was studied during plant cold hardening (3°0C, 3 days). The sensitivity of subcellular structures to oryzalin depended closely on cell metabolic activity and the extent of development of the cortical microtubule (MT) network. Most pronounced oryzalin-induced changes were related to enhanced cell vacuolation and the appearance of some signs of apoptosis (as judged from cytoplasm fragmentation) in some cells. In the root zone examined, cell heterogeneity increased, when, along with normally functioning cells, dramatically damaged and even completely destroyed cells appeared. Simultaneously, the activity of cyanide-resistant nonphosphorylating respiration pathway was activated, especially during cold hardening. In hardened cells, single cortical microtubules appeared in both wheat cultivars; this fact indicates that new cold-resistant subpopulations of MT were resistant to depolymerizing action of oryzalin. © MAIK "Nauka/Interperiodica", 2006