Anna Rychter - Academia.edu (original) (raw)

Papers by Anna Rychter

Alternative respiratory pathways in higher plants, 2015

Annals of Botany, 2006

(and ultimately, on the survival of humanity) of plant breeding, artificial selection and genetic... more (and ultimately, on the survival of humanity) of plant breeding, artificial selection and genetic engineering. We find this in chapter 9. The author is very even-handed, and points out the pros and cons of our manipulation of plants for sproductivity, profit and sustainable livelihoods. In the final chapter, 10, the author writes about the end of Eden. The consequences of deforestation, monoculture, overgrazing and ruining of natural ecosystems by our interference or management are explored, first in Mexico, but we are taken to other parts of the world for additional examples. The book concludes in a somewhat more positive vein, with suggestions of ways in which we can turn the tide of destruction if we really have the will, and examples are provided of where this is already taking place. Specialist books may deal with these aspects in greater depth, but the essential arguments are presented here. This book deserves to be taken seriously. It is written so that the non-expert can get a sound understanding of difficult ecological and evolutionary principles. It is not beyond the grasp of policy makers and politicians, and might be described as required reading by people who will shape the future of our planet.

Planta, 2010

The MSC16 cucumber (Cucumis sativus L.) mitochondrial mutant was used to study the effect of mito... more The MSC16 cucumber (Cucumis sativus L.) mitochondrial mutant was used to study the effect of mitochondrial dysfunction and disturbed subcellular redox state on leaf day/night carbon and nitrogen metabolism. We have shown that the mitochondrial dysfunction in MSC16 plants had no effect on photosynthetic CO 2 assimilation, but the concentration of soluble carbohydrates and starch was higher in leaves of MSC16 plants. Impaired mitochondrial respiratory chain activity was associated with the perturbation of mitochondrial TCA cycle manifested, e.g., by lowered decarboxylation rate. Mitochondrial dysfunction in MSC16 plants had different influence on leaf cell metabolism under dark or light conditions. In the dark, when the main mitochondrial function is the energy production, the altered activity of TCA cycle in mutated plants was connected with the accumulation of pyruvate and TCA cycle intermediates (citrate and 2-OG). In the light, when TCA activity is needed for synthesis of carbon skeletons required as the acceptors for NH 4 ? assimilation, the concentration of pyruvate and TCA intermediates was tightly coupled with nitrate metabolism. Enhanced incorporation of ammonium group into amino acids structures in mutated plants has resulted in decreased concentration of organic acids and accumulation of Glu.

Plant Science, 2000

Electrophoresis mobility shift assay (EMSA) identified nuclear proteins with binding activity to ... more Electrophoresis mobility shift assay (EMSA) identified nuclear proteins with binding activity to a 430 bp promoter fragment of the Sorghum C 4 phosphoenolpyruvate carboxylase gene (S6C4). The DNA binding activities (two main retarded bands; PC1 and PC2) were high in nuclear extracts from etiolated leaves, decreased during greening and became very low or null in nuclear extracts from green leaves. This process was found to be mediated by phytochrome and was apparently irreversible since the DNA-binding activities were not restored in green plants kept in continuous darkness. The AT-rich region of the promoter fragment was identified to be the interaction domain of PC2. The detection of PC2 with EMSA was markedly reduced by preincubation of nuclear protein extracts with Mg-ATP or Mg-GTP and restored in the presence of a general protein serine/threonine-kinase inhibitor, K252a. The results suggested that the PC2 binding activity was modulated by phosphorylation during the greening process of the Sorghum leaf.

PLANT PHYSIOLOGY, 1979

Ethylene, cyanide gas, and volatalized ethanol, acetaldehyde, and acetic acid were appled in a co... more Ethylene, cyanide gas, and volatalized ethanol, acetaldehyde, and acetic acid were appled in a continuous flow to whole potato tubers. Freshly cut slices were obtained periodically during the treatment, and showed a progressive development of a cyanide-resistant respiration. The appUcation of the employed volatiles in 100% 02 accelerated the onset and the magnitude of the cyanide-resistant respiration. These results show that, similar to ethylene and cyanide, the appUcation of ethanol, acetaldehyde, or acetic acid can also lead to the development of cyanide-resistant respiration in whole potato tubers, and that this type of respiration is retained in freshly cut slices.

PLANT PHYSIOLOGY, 1979

Ethanol, acetaldehyde, and acetic acid, when applied in a volatile state in air to potato tubers,... more Ethanol, acetaldehyde, and acetic acid, when applied in a volatile state in air to potato tubers, led to a climacteric-like upsurge in respiration. The respiratory upsurge was markedly enhanced when the volatiles were applied in 100% 02. Ethanol induced a decline in the level of 2-phosphoglyceric acid and phosphoenolpyruvate while leading tu the accumulation of tricarboxylic acid cycle intermediates including isocitrate and a-ketoglutarate. The action of these compounds was similar to, but independent of, the action of ethylene.

PLANT PHYSIOLOGY, 1979

Mitochondria from whole potatoes (Solanum tuberosum) ordinarily fail to oxidize respiratory subst... more Mitochondria from whole potatoes (Solanum tuberosum) ordinarily fail to oxidize respiratory substrates and to consume molecular 02 in the presence of cyanide. Mitochondrial preparations obtained from tubers previously held for 24 hours in ethylene (10 microliters per liter) in air are only partially inhibited by cyanide. Application of ethylene in 100% 02 led to an additional increase in the resistance of the mitochondrial respiration to cyanide. The resistance to cyanide was accompanied by a decrease in the respiratory control but no change in oxidative phosphorylation as shown by the measurement of ATP synthesis. The development of resistance to cyanide following the application of ethylene appears to require whole tubers and may represent an inductive process.

PLANT PHYSIOLOGY, 1978

Treating Intact white potato (Solaum tuberosuzn L) tuber with ethykne In air or 02 made it possib... more Treating Intact white potato (Solaum tuberosuzn L) tuber with ethykne In air or 02 made it possible to obtain freshly cut sflces which exhibt cyaaide-resbtaat respirat The cyaaie-resistaat path requIr inductin In whole tubers. The data also dicate that high 02 concentration is necessary for the ful developmet of cyanie-resitant respieAtkon

Plant and Soil, 2004

The effect of prolonged phosphate starvation of bean plants (Phaseolus vulgaris L.) on the concen... more The effect of prolonged phosphate starvation of bean plants (Phaseolus vulgaris L.) on the concentration of phenolics and their exudation by roots was studied. Plants cultured on phosphate-deficient media maintained a steady concentration of total phenolics in the leaves, whereas in the leaves of plants grown on complete nutrient media the phenolic concentration decreased. After 18 days of culture, higher total phenolics and anthocyanin concentrations in phosphate-deficient leaves compared with control leaves were observed. The divergent trends in total phenolic concentrations between phosphate-deficient and control leaves corresponded to the changes in the activity of L-phenylalanine ammonia-lyase. In the roots, the concentration of total phenolics was lower in phosphate-deficient plants compared with control plants. However, after 18 days of culture of bean plants, the amount of exuded phenolics from phosphate-deficient roots was 5-times higher than that from the roots of control plants. The activity of L-phenylalanine ammonia-lyase was twice as high in the roots of phosphate-starved plants. Comparable rates in the exudation of phenolics by bean roots observed after 18 days of culture on nitrogen-deficient or phosphate-deficient medium may suggest a similar system of signal transduction for phenolics release. The results are discussed in relation to the possible functions of phenolics in nutrient uptake and as chemical signals in root-soil microbe interactions to enhance the plant adaptation to particular environmental conditions.

Physiologia Plantarum, 1994

Bean plants (Phaseolus vulgaris) grown in phosphate-deficient (-P) medium display deficiency symp... more Bean plants (Phaseolus vulgaris) grown in phosphate-deficient (-P) medium display deficiency symptoms after about 2 weeks of culture. A decrease in inorganic phosphate level in roots was ohserved after 10 days of culture, and after 17 days it was more than 30 times less than control. The drj' weight of the .shoots of phosphate-deficient plants was lower whereas tbe drj' weight of the roots was higher as compared to the control roots. After 2 weeks of culture, the sucrose level in-P roots almosf doubled compared tO' coMrol roots. An increase io glucose and fructose was ohserved earlier than that of sucrose, and after 10 days of culture in phosphate-deficient medium the glucose level in-P roots was about 3 times higher than that in +P roots. At the same time, a decrease in hexose-phosphate level was ohserved. This decrease may reflect a higher drain from the hexose phosphate pool, or it may he due to the lower capacity for hexose phosphorylation of phosphate-deficient plants, as judged by the lower hexokinase and fructokinase activities. The ratio of non-phosphorylated to phosphorj'lated sugars in-P roots was about 5 times higher as compared to contro] roots. We propose that glucose and fructose accumulation in phosphate-deficient roots represents a non-metabolic, probably vaeuolar pool which is not utilized for growth and metabolism of the roots.

Physiologia Plantarum, 2009

Biologia plantarum, 1994

Iron starved dicotyledonous plants undergo several modification aimed at increasing iron assimila... more Iron starved dicotyledonous plants undergo several modification aimed at increasing iron assimilation, including enhanced plasma-membrane linked redox activities in roots (1). Monocots are known to regulate their iron requirement mainly by release of phytosiderophores. However a plasma-membrane associated Fe3+-ehelate reduetase activity exists in maize and is modulated by iron starvation. This increase is partly a consequence of the more abundant plasma membrane material found as part of an iron starvation syndrome affecting also root morphology (fresh mass +30 %). Molecular mass determinations of solubilized plasma-membrane or microsomes by means of FPLC size-exclusion chromatography identify a 210 kDa protein in both control and stressed material solubilized with 2 % (m/v) lysopbophatidylcholine. This protein appears to be very sensitive to freezing-thawing, high salt and dilution. After exposure to such conditions the activity is partially recovered (25 %) associated to 43 and 26 kDa forms tentatively identified as subunits of the 210 kDa (see also refs. 2,3). Other detergents directly give rise to such low molecular mass forms. These are also found in the supernatant fraction.

Plant, Cell & Environment, 2011

Mutations in a mitochondrial or nuclear gene encoding respiratory chain complex I subunits lead t... more Mutations in a mitochondrial or nuclear gene encoding respiratory chain complex I subunits lead to decreased or a total absence of complex I activity. Plant mutants with altered or lost complex I activity adapt their respiratory metabolism by inducing alternative pathways of the respiratory chain and changing energy metabolism. Apparently, complex I is a crucial component of the oxidationreduction (redox) regulatory system in photosynthetic cells, and alternative NAD(P)H dehydrogenases of the mitochondrial electron transport chain (mtETC) cannot fully compensate for its impairment. In most cases, dysfunction of complex I is associated with lowered or unchanged hydrogen peroxide (H2O2) concentrations, but increased superoxide (O2-) levels. Higher production of reactive oxygen species (ROS) by mitochondria in the mosaic (MSC16) cucumber mutant may be related to retrograde signalling. Different effects of complex I dysfunction on H2O2 and O2levels in described mutants might result from diverse regulation of processes involved in H2O2 and O2production. Often, dysfunction of complex I did not lead to oxidative stress, but increased the capacity of the antioxidative system and enhanced stress tolerance. The new cellular homeostasis in mutants with dysfunction of complex I allows growth and development, reflecting the plasticity of plant metabolism.

Acta Physiologiae Plantarum, 1999

... nolamine (PE) were two major phospholipids in each membrane (Table 3), similarly as estimated... more ... nolamine (PE) were two major phospholipids in each membrane (Table 3), similarly as estimated in soybean (Whitman and Travis 1985), barley ... of phosphate deprivation on total protein and lipid content was investigated in a Brassica nigra cell suspension culture (Fife et al. ...

Physiologia Plantarum, 2007

The effects of changes in mitochondrial DNA in cucumber (Cucumis sativus L.) mosaic mutant (MSC16... more The effects of changes in mitochondrial DNA in cucumber (Cucumis sativus L.) mosaic mutant (MSC16) on respiration, photosynthesis and photorespiration were analyzed under non-stressed conditions. Decreased respiratory capacity of complex I in MSC16 mitochondria was indicated by lower respiration rates of intact mitochondria with malate and by rotenone-inhibited NADH or malate oxidation in the presence of alamethicin. Moreover, blue native PAGE indicated decreased intensity of protein bands of respiratory chain complex I in MSC16 leaves. Concerning the redox state, complex I impairment could be compensated to some extent by increased external NADH dehydrogenases (ND ex NADH) and alternative oxidase (AOX) capacity, the latter presenting differential expression in the light and in the dark. Although MSC16 mitochondria have a higher AOX protein level and an increased capacity, the AOX activity measured in the dark conditions by oxygen discrimination technique is similar to that in wild-type (WT) plants. Photosynthesis induction by light followed different patterns in WT and MSC16, suggesting changes in feedback chloroplast DpH caused by different adenylate levels. At steady-state, net photosynthesis was only slightly impaired in MSC16 mutants, while photorespiration rate (PR) was significantly increased. This was the result of large decreases in both stomatal and mesophyll conductance to CO 2 , which resulted in a lower CO 2 concentration in the chloroplasts. The observed changes on CO 2 diffusion caused by mitochondrial mutations open a whole new view of interaction between organelle metabolism and whole tissue physiology. The sum of all the described changes in photosynthetic and respiratory metabolism resulted in a lower ATP availability and a slower plant growth.

Physiologia Plantarum, 2009

In vitro studies demonstrated that alternative oxidase (AOX) is biochemically regulated by a sulf... more In vitro studies demonstrated that alternative oxidase (AOX) is biochemically regulated by a sulfhydryl-disulfide system, interaction with α-ketoacids, ubiquinone pool redox state and protein content among others. However, there is still scarce information about the in vivo regulation of the AOX. Cucumis sativus wild-type (WT) and MSC16 mutant plants were grown under two different light intensities and were used to analyze the relationship between the amount of leaf AOX protein and its in vivo capacity and activity at night and day periods. WT and MSC16 plants presented lower total respiration (V t), cytochrome oxidase pathway (COP) activity (v cyt) and alternative oxidase pathway (AOP) activity (v alt) when grown at low light (LL), although growth light intensity did not change the amount of cytochrome oxidase (COX) nor AOX protein. Changes of v cyt related to growing light conditions suggested a substrate availability and energy demand control. On the other hand, the total amount of AOX protein present in the tissue does not play a role in the regulation neither of the capacity nor of the activity of the AOP in vivo. Soluble carbohydrates were directly related to the activity of the AOP. However, although differences in soluble sugar contents mostly regulate the capacity of the AOP at different growth light intensities, additional regulatory mechanisms are necessary to fully explain the observed results.

Biologia Plantarum, 1998

The decrease in inorganic phosphate concentration in bean (Phaseolus vulgaris L. cv. Złota Saxa) ... more The decrease in inorganic phosphate concentration in bean (Phaseolus vulgaris L. cv. Złota Saxa) roots induced decrease in respiration rate. The decrease observed in ATP pool in phosphate deficient (-P) roots was greater than it would result from the decline in respiration and possible involvement of alternative pathway, suggesting an increased energy utilization for growth and ion uptake. Indeed, relative

Annals of Botany

Bean plants (Phaseolus ulgaris L. ' Zlota Saxa ') were cultured on complete (jP) or phosphate-def... more Bean plants (Phaseolus ulgaris L. ' Zlota Saxa ') were cultured on complete (jP) or phosphate-deficient (kP) nutrient medium. A large increase in glucose concentration was found in the meristematic zone of kP roots compared to control roots. The increased glucose concentration in the meristematic zone did not influence total respiration rate. Glucose or uncoupler (carbonyl cyanide m-chlorophenylhydrazone) failed to increase the respiration rate in kP root segments, but stimulated respiration in jP roots. The ultrastructure of cortical cells from the meristematic root zone showed marked differences between jP and kP plants. Large vacuoles, invaginations of the plasmalemma and condensed forms of mitochondria were dominating features in cortical cells of kP roots. Analysis of extracts after treating roots with dimethylsulfoxide (DMSO) indicated different localization of sugars in the cell compartments. In roots of kP plants, most of the reducing sugars were detected in the cytoplasm fraction while most sucrose was in the vacuole. Observations of the effect of 10 % DMSO on cell ultrastructure indicated partial destruction of the plasmalemma but not the tonoplast. The localization of reducing sugars in secondary vacuoles or plasmalemma invaginations in the cells from the meristematic region of kP roots is discussed.

Alternative respiratory pathways in higher plants, 2015

Annals of Botany, 2006

(and ultimately, on the survival of humanity) of plant breeding, artificial selection and genetic... more (and ultimately, on the survival of humanity) of plant breeding, artificial selection and genetic engineering. We find this in chapter 9. The author is very even-handed, and points out the pros and cons of our manipulation of plants for sproductivity, profit and sustainable livelihoods. In the final chapter, 10, the author writes about the end of Eden. The consequences of deforestation, monoculture, overgrazing and ruining of natural ecosystems by our interference or management are explored, first in Mexico, but we are taken to other parts of the world for additional examples. The book concludes in a somewhat more positive vein, with suggestions of ways in which we can turn the tide of destruction if we really have the will, and examples are provided of where this is already taking place. Specialist books may deal with these aspects in greater depth, but the essential arguments are presented here. This book deserves to be taken seriously. It is written so that the non-expert can get a sound understanding of difficult ecological and evolutionary principles. It is not beyond the grasp of policy makers and politicians, and might be described as required reading by people who will shape the future of our planet.

Planta, 2010

The MSC16 cucumber (Cucumis sativus L.) mitochondrial mutant was used to study the effect of mito... more The MSC16 cucumber (Cucumis sativus L.) mitochondrial mutant was used to study the effect of mitochondrial dysfunction and disturbed subcellular redox state on leaf day/night carbon and nitrogen metabolism. We have shown that the mitochondrial dysfunction in MSC16 plants had no effect on photosynthetic CO 2 assimilation, but the concentration of soluble carbohydrates and starch was higher in leaves of MSC16 plants. Impaired mitochondrial respiratory chain activity was associated with the perturbation of mitochondrial TCA cycle manifested, e.g., by lowered decarboxylation rate. Mitochondrial dysfunction in MSC16 plants had different influence on leaf cell metabolism under dark or light conditions. In the dark, when the main mitochondrial function is the energy production, the altered activity of TCA cycle in mutated plants was connected with the accumulation of pyruvate and TCA cycle intermediates (citrate and 2-OG). In the light, when TCA activity is needed for synthesis of carbon skeletons required as the acceptors for NH 4 ? assimilation, the concentration of pyruvate and TCA intermediates was tightly coupled with nitrate metabolism. Enhanced incorporation of ammonium group into amino acids structures in mutated plants has resulted in decreased concentration of organic acids and accumulation of Glu.

Plant Science, 2000

Electrophoresis mobility shift assay (EMSA) identified nuclear proteins with binding activity to ... more Electrophoresis mobility shift assay (EMSA) identified nuclear proteins with binding activity to a 430 bp promoter fragment of the Sorghum C 4 phosphoenolpyruvate carboxylase gene (S6C4). The DNA binding activities (two main retarded bands; PC1 and PC2) were high in nuclear extracts from etiolated leaves, decreased during greening and became very low or null in nuclear extracts from green leaves. This process was found to be mediated by phytochrome and was apparently irreversible since the DNA-binding activities were not restored in green plants kept in continuous darkness. The AT-rich region of the promoter fragment was identified to be the interaction domain of PC2. The detection of PC2 with EMSA was markedly reduced by preincubation of nuclear protein extracts with Mg-ATP or Mg-GTP and restored in the presence of a general protein serine/threonine-kinase inhibitor, K252a. The results suggested that the PC2 binding activity was modulated by phosphorylation during the greening process of the Sorghum leaf.

PLANT PHYSIOLOGY, 1979

Ethylene, cyanide gas, and volatalized ethanol, acetaldehyde, and acetic acid were appled in a co... more Ethylene, cyanide gas, and volatalized ethanol, acetaldehyde, and acetic acid were appled in a continuous flow to whole potato tubers. Freshly cut slices were obtained periodically during the treatment, and showed a progressive development of a cyanide-resistant respiration. The appUcation of the employed volatiles in 100% 02 accelerated the onset and the magnitude of the cyanide-resistant respiration. These results show that, similar to ethylene and cyanide, the appUcation of ethanol, acetaldehyde, or acetic acid can also lead to the development of cyanide-resistant respiration in whole potato tubers, and that this type of respiration is retained in freshly cut slices.

PLANT PHYSIOLOGY, 1979

Ethanol, acetaldehyde, and acetic acid, when applied in a volatile state in air to potato tubers,... more Ethanol, acetaldehyde, and acetic acid, when applied in a volatile state in air to potato tubers, led to a climacteric-like upsurge in respiration. The respiratory upsurge was markedly enhanced when the volatiles were applied in 100% 02. Ethanol induced a decline in the level of 2-phosphoglyceric acid and phosphoenolpyruvate while leading tu the accumulation of tricarboxylic acid cycle intermediates including isocitrate and a-ketoglutarate. The action of these compounds was similar to, but independent of, the action of ethylene.

PLANT PHYSIOLOGY, 1979

Mitochondria from whole potatoes (Solanum tuberosum) ordinarily fail to oxidize respiratory subst... more Mitochondria from whole potatoes (Solanum tuberosum) ordinarily fail to oxidize respiratory substrates and to consume molecular 02 in the presence of cyanide. Mitochondrial preparations obtained from tubers previously held for 24 hours in ethylene (10 microliters per liter) in air are only partially inhibited by cyanide. Application of ethylene in 100% 02 led to an additional increase in the resistance of the mitochondrial respiration to cyanide. The resistance to cyanide was accompanied by a decrease in the respiratory control but no change in oxidative phosphorylation as shown by the measurement of ATP synthesis. The development of resistance to cyanide following the application of ethylene appears to require whole tubers and may represent an inductive process.

PLANT PHYSIOLOGY, 1978

Treating Intact white potato (Solaum tuberosuzn L) tuber with ethykne In air or 02 made it possib... more Treating Intact white potato (Solaum tuberosuzn L) tuber with ethykne In air or 02 made it possible to obtain freshly cut sflces which exhibt cyaaide-resbtaat respirat The cyaaie-resistaat path requIr inductin In whole tubers. The data also dicate that high 02 concentration is necessary for the ful developmet of cyanie-resitant respieAtkon

Plant and Soil, 2004

The effect of prolonged phosphate starvation of bean plants (Phaseolus vulgaris L.) on the concen... more The effect of prolonged phosphate starvation of bean plants (Phaseolus vulgaris L.) on the concentration of phenolics and their exudation by roots was studied. Plants cultured on phosphate-deficient media maintained a steady concentration of total phenolics in the leaves, whereas in the leaves of plants grown on complete nutrient media the phenolic concentration decreased. After 18 days of culture, higher total phenolics and anthocyanin concentrations in phosphate-deficient leaves compared with control leaves were observed. The divergent trends in total phenolic concentrations between phosphate-deficient and control leaves corresponded to the changes in the activity of L-phenylalanine ammonia-lyase. In the roots, the concentration of total phenolics was lower in phosphate-deficient plants compared with control plants. However, after 18 days of culture of bean plants, the amount of exuded phenolics from phosphate-deficient roots was 5-times higher than that from the roots of control plants. The activity of L-phenylalanine ammonia-lyase was twice as high in the roots of phosphate-starved plants. Comparable rates in the exudation of phenolics by bean roots observed after 18 days of culture on nitrogen-deficient or phosphate-deficient medium may suggest a similar system of signal transduction for phenolics release. The results are discussed in relation to the possible functions of phenolics in nutrient uptake and as chemical signals in root-soil microbe interactions to enhance the plant adaptation to particular environmental conditions.

Physiologia Plantarum, 1994

Bean plants (Phaseolus vulgaris) grown in phosphate-deficient (-P) medium display deficiency symp... more Bean plants (Phaseolus vulgaris) grown in phosphate-deficient (-P) medium display deficiency symptoms after about 2 weeks of culture. A decrease in inorganic phosphate level in roots was ohserved after 10 days of culture, and after 17 days it was more than 30 times less than control. The drj' weight of the .shoots of phosphate-deficient plants was lower whereas tbe drj' weight of the roots was higher as compared to the control roots. After 2 weeks of culture, the sucrose level in-P roots almosf doubled compared tO' coMrol roots. An increase io glucose and fructose was ohserved earlier than that of sucrose, and after 10 days of culture in phosphate-deficient medium the glucose level in-P roots was about 3 times higher than that in +P roots. At the same time, a decrease in hexose-phosphate level was ohserved. This decrease may reflect a higher drain from the hexose phosphate pool, or it may he due to the lower capacity for hexose phosphorylation of phosphate-deficient plants, as judged by the lower hexokinase and fructokinase activities. The ratio of non-phosphorylated to phosphorj'lated sugars in-P roots was about 5 times higher as compared to contro] roots. We propose that glucose and fructose accumulation in phosphate-deficient roots represents a non-metabolic, probably vaeuolar pool which is not utilized for growth and metabolism of the roots.

Physiologia Plantarum, 2009

Biologia plantarum, 1994

Iron starved dicotyledonous plants undergo several modification aimed at increasing iron assimila... more Iron starved dicotyledonous plants undergo several modification aimed at increasing iron assimilation, including enhanced plasma-membrane linked redox activities in roots (1). Monocots are known to regulate their iron requirement mainly by release of phytosiderophores. However a plasma-membrane associated Fe3+-ehelate reduetase activity exists in maize and is modulated by iron starvation. This increase is partly a consequence of the more abundant plasma membrane material found as part of an iron starvation syndrome affecting also root morphology (fresh mass +30 %). Molecular mass determinations of solubilized plasma-membrane or microsomes by means of FPLC size-exclusion chromatography identify a 210 kDa protein in both control and stressed material solubilized with 2 % (m/v) lysopbophatidylcholine. This protein appears to be very sensitive to freezing-thawing, high salt and dilution. After exposure to such conditions the activity is partially recovered (25 %) associated to 43 and 26 kDa forms tentatively identified as subunits of the 210 kDa (see also refs. 2,3). Other detergents directly give rise to such low molecular mass forms. These are also found in the supernatant fraction.

Plant, Cell & Environment, 2011

Mutations in a mitochondrial or nuclear gene encoding respiratory chain complex I subunits lead t... more Mutations in a mitochondrial or nuclear gene encoding respiratory chain complex I subunits lead to decreased or a total absence of complex I activity. Plant mutants with altered or lost complex I activity adapt their respiratory metabolism by inducing alternative pathways of the respiratory chain and changing energy metabolism. Apparently, complex I is a crucial component of the oxidationreduction (redox) regulatory system in photosynthetic cells, and alternative NAD(P)H dehydrogenases of the mitochondrial electron transport chain (mtETC) cannot fully compensate for its impairment. In most cases, dysfunction of complex I is associated with lowered or unchanged hydrogen peroxide (H2O2) concentrations, but increased superoxide (O2-) levels. Higher production of reactive oxygen species (ROS) by mitochondria in the mosaic (MSC16) cucumber mutant may be related to retrograde signalling. Different effects of complex I dysfunction on H2O2 and O2levels in described mutants might result from diverse regulation of processes involved in H2O2 and O2production. Often, dysfunction of complex I did not lead to oxidative stress, but increased the capacity of the antioxidative system and enhanced stress tolerance. The new cellular homeostasis in mutants with dysfunction of complex I allows growth and development, reflecting the plasticity of plant metabolism.

Acta Physiologiae Plantarum, 1999

... nolamine (PE) were two major phospholipids in each membrane (Table 3), similarly as estimated... more ... nolamine (PE) were two major phospholipids in each membrane (Table 3), similarly as estimated in soybean (Whitman and Travis 1985), barley ... of phosphate deprivation on total protein and lipid content was investigated in a Brassica nigra cell suspension culture (Fife et al. ...

Physiologia Plantarum, 2007

The effects of changes in mitochondrial DNA in cucumber (Cucumis sativus L.) mosaic mutant (MSC16... more The effects of changes in mitochondrial DNA in cucumber (Cucumis sativus L.) mosaic mutant (MSC16) on respiration, photosynthesis and photorespiration were analyzed under non-stressed conditions. Decreased respiratory capacity of complex I in MSC16 mitochondria was indicated by lower respiration rates of intact mitochondria with malate and by rotenone-inhibited NADH or malate oxidation in the presence of alamethicin. Moreover, blue native PAGE indicated decreased intensity of protein bands of respiratory chain complex I in MSC16 leaves. Concerning the redox state, complex I impairment could be compensated to some extent by increased external NADH dehydrogenases (ND ex NADH) and alternative oxidase (AOX) capacity, the latter presenting differential expression in the light and in the dark. Although MSC16 mitochondria have a higher AOX protein level and an increased capacity, the AOX activity measured in the dark conditions by oxygen discrimination technique is similar to that in wild-type (WT) plants. Photosynthesis induction by light followed different patterns in WT and MSC16, suggesting changes in feedback chloroplast DpH caused by different adenylate levels. At steady-state, net photosynthesis was only slightly impaired in MSC16 mutants, while photorespiration rate (PR) was significantly increased. This was the result of large decreases in both stomatal and mesophyll conductance to CO 2 , which resulted in a lower CO 2 concentration in the chloroplasts. The observed changes on CO 2 diffusion caused by mitochondrial mutations open a whole new view of interaction between organelle metabolism and whole tissue physiology. The sum of all the described changes in photosynthetic and respiratory metabolism resulted in a lower ATP availability and a slower plant growth.

Physiologia Plantarum, 2009

In vitro studies demonstrated that alternative oxidase (AOX) is biochemically regulated by a sulf... more In vitro studies demonstrated that alternative oxidase (AOX) is biochemically regulated by a sulfhydryl-disulfide system, interaction with α-ketoacids, ubiquinone pool redox state and protein content among others. However, there is still scarce information about the in vivo regulation of the AOX. Cucumis sativus wild-type (WT) and MSC16 mutant plants were grown under two different light intensities and were used to analyze the relationship between the amount of leaf AOX protein and its in vivo capacity and activity at night and day periods. WT and MSC16 plants presented lower total respiration (V t), cytochrome oxidase pathway (COP) activity (v cyt) and alternative oxidase pathway (AOP) activity (v alt) when grown at low light (LL), although growth light intensity did not change the amount of cytochrome oxidase (COX) nor AOX protein. Changes of v cyt related to growing light conditions suggested a substrate availability and energy demand control. On the other hand, the total amount of AOX protein present in the tissue does not play a role in the regulation neither of the capacity nor of the activity of the AOP in vivo. Soluble carbohydrates were directly related to the activity of the AOP. However, although differences in soluble sugar contents mostly regulate the capacity of the AOP at different growth light intensities, additional regulatory mechanisms are necessary to fully explain the observed results.

Biologia Plantarum, 1998

The decrease in inorganic phosphate concentration in bean (Phaseolus vulgaris L. cv. Złota Saxa) ... more The decrease in inorganic phosphate concentration in bean (Phaseolus vulgaris L. cv. Złota Saxa) roots induced decrease in respiration rate. The decrease observed in ATP pool in phosphate deficient (-P) roots was greater than it would result from the decline in respiration and possible involvement of alternative pathway, suggesting an increased energy utilization for growth and ion uptake. Indeed, relative

Annals of Botany

Bean plants (Phaseolus ulgaris L. ' Zlota Saxa ') were cultured on complete (jP) or phosphate-def... more Bean plants (Phaseolus ulgaris L. ' Zlota Saxa ') were cultured on complete (jP) or phosphate-deficient (kP) nutrient medium. A large increase in glucose concentration was found in the meristematic zone of kP roots compared to control roots. The increased glucose concentration in the meristematic zone did not influence total respiration rate. Glucose or uncoupler (carbonyl cyanide m-chlorophenylhydrazone) failed to increase the respiration rate in kP root segments, but stimulated respiration in jP roots. The ultrastructure of cortical cells from the meristematic root zone showed marked differences between jP and kP plants. Large vacuoles, invaginations of the plasmalemma and condensed forms of mitochondria were dominating features in cortical cells of kP roots. Analysis of extracts after treating roots with dimethylsulfoxide (DMSO) indicated different localization of sugars in the cell compartments. In roots of kP plants, most of the reducing sugars were detected in the cytoplasm fraction while most sucrose was in the vacuole. Observations of the effect of 10 % DMSO on cell ultrastructure indicated partial destruction of the plasmalemma but not the tonoplast. The localization of reducing sugars in secondary vacuoles or plasmalemma invaginations in the cells from the meristematic region of kP roots is discussed.