Pub Date : 2012-12-01DOI: 10.1590/S1677-04202012000400007
Q. Fariduddin, B. Mir, A. Ahmad
The present study was conducted to evaluate salt tolerance in seven different pure-line cultivars of tomato (Solanum lycopersicum L.) viz. K-21, Pusa Ruby, Pusa Gorav, Hera research, Selection N5, PKM-1 and S-22 based on several physiological and biochemical traits. Seedlings were transplanted to the pots, being exposed to different salinity levels in the form of NaCl (0, 50, 100, or 150 mM) at a 35-day stage of growth for six days. The plants exposed to salt stress presented a significant decline in growth, photosynthetic parameters, maximum quantum yield of PSII and leaf water relations, which were drastically reduced in variety S-22, while variety K-21 was the least affected. Electrolyte leakage was superior in proportion to an increase in salinity levels. Proline content and activity of antioxidant enzymes catalase, peroxidase, and superoxide dismutase were found maximum in variety K-21. Almost all the growth and physiological and biochemical traits had a significant genotypic variation, indicating that these parameters could be used as novel screening criteria for selecting the tolerant and sensitive cultivars exposed to salt stress.
{"title":"Physiological and biochemical traits as tools to screen sensitive and resistant varieties of tomatoes exposed to salt stress","authors":"Q. Fariduddin, B. Mir, A. Ahmad","doi":"10.1590/S1677-04202012000400007","DOIUrl":"https://doi.org/10.1590/S1677-04202012000400007","url":null,"abstract":"The present study was conducted to evaluate salt tolerance in seven different pure-line cultivars of tomato (Solanum lycopersicum L.) viz. K-21, Pusa Ruby, Pusa Gorav, Hera research, Selection N5, PKM-1 and S-22 based on several physiological and biochemical traits. Seedlings were transplanted to the pots, being exposed to different salinity levels in the form of NaCl (0, 50, 100, or 150 mM) at a 35-day stage of growth for six days. The plants exposed to salt stress presented a significant decline in growth, photosynthetic parameters, maximum quantum yield of PSII and leaf water relations, which were drastically reduced in variety S-22, while variety K-21 was the least affected. Electrolyte leakage was superior in proportion to an increase in salinity levels. Proline content and activity of antioxidant enzymes catalase, peroxidase, and superoxide dismutase were found maximum in variety K-21. Almost all the growth and physiological and biochemical traits had a significant genotypic variation, indicating that these parameters could be used as novel screening criteria for selecting the tolerant and sensitive cultivars exposed to salt stress.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89030110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1590/S1677-04202012000400001
P. Mazzafera, R. Azevedo
{"title":"An overview of the Brazilian Journal of Plant Physiology: we need a push!","authors":"P. Mazzafera, R. Azevedo","doi":"10.1590/S1677-04202012000400001","DOIUrl":"https://doi.org/10.1590/S1677-04202012000400001","url":null,"abstract":"","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75945192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1590/S1677-04202012000400008
M. P. Gomes, T. Marques, G. Martins, M. M. L. C. Carneiro, Â. Soares
Physiological and anatomical features of Cd-tolerance in Pfaffia glomerata were examined by exposing plantlets to nutrient solutions with increasing Cd concentrations (0, 15, 45, and 90 µmol Cd L-1), and possible Cd-tolerance markers were established. Cd contents were found to be higher in roots than in shoots. According to the bio-concentration factor data, this species is effectively a Cd-hyperaccumulator, as previously attested. Cd induced the appearance of xeromorphic characteristics in leaves (decreased water potential, increased numbers and decreased stomata size) and increased root endodermis thickness. The enzymatic antioxidant systems of roots and leaves were differently affected by Cd. The coordinated activities of antioxidant enzymes were effective in reducing Cd-induced reactive oxygen species in plants, mainly in leaves. Root endodermis thickness, stomatal size and numbers, root superoxide dismutase, and guaiacol peroxidase, as well as leaf guaiacol peroxidase and catalase activities can all be considered Cd-tolerance markers in Pfaffia glomerata. Due to its high root Cd accumulation, Pfaffia glomerata may be useful in Cd-phytoextraction programs, however the pharmacological use of plants grown in the presence of Cd must be avoided.
{"title":"Cd-tolerance markers of Pfaffia glomerata (Spreng.) Pedersen plants: anatomical and physiological features","authors":"M. P. Gomes, T. Marques, G. Martins, M. M. L. C. Carneiro, Â. Soares","doi":"10.1590/S1677-04202012000400008","DOIUrl":"https://doi.org/10.1590/S1677-04202012000400008","url":null,"abstract":"Physiological and anatomical features of Cd-tolerance in Pfaffia glomerata were examined by exposing plantlets to nutrient solutions with increasing Cd concentrations (0, 15, 45, and 90 µmol Cd L-1), and possible Cd-tolerance markers were established. Cd contents were found to be higher in roots than in shoots. According to the bio-concentration factor data, this species is effectively a Cd-hyperaccumulator, as previously attested. Cd induced the appearance of xeromorphic characteristics in leaves (decreased water potential, increased numbers and decreased stomata size) and increased root endodermis thickness. The enzymatic antioxidant systems of roots and leaves were differently affected by Cd. The coordinated activities of antioxidant enzymes were effective in reducing Cd-induced reactive oxygen species in plants, mainly in leaves. Root endodermis thickness, stomatal size and numbers, root superoxide dismutase, and guaiacol peroxidase, as well as leaf guaiacol peroxidase and catalase activities can all be considered Cd-tolerance markers in Pfaffia glomerata. Due to its high root Cd accumulation, Pfaffia glomerata may be useful in Cd-phytoextraction programs, however the pharmacological use of plants grown in the presence of Cd must be avoided.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80925890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1590/S1677-04202013005000001
E. G. Martinazzo, Aline Ramm, M. A. Bacarin
Plants growing in temperate regions are often exposed to stress conditions caused by high temperatures. Photosynthesis is one of the metabolic processes most sensitive to high temperature stress, and it is often inhibited before other cellular functions. Using peach leaf disks, we studied the transient chlorophyll a fluorescence along with the gas exchanges at temperatures of 25 (control) 30, 35, 40 and 45°C in the dark for a period of 30 minutes. Temperatures above 35°C caused significant changes in the transient fluorescence of chlorophyll a, including an increase in the initial fluorescence (F0), a decrease in maximum fluorescence values (FM) and the appearance of K and L bands. The values of the net assimilation rate decreased as the temperature increased and reached negative values at 45°C.
{"title":"The chlorophyll a fluorescence as an indicator of the temperature stress in the leaves of Prunus persica","authors":"E. G. Martinazzo, Aline Ramm, M. A. Bacarin","doi":"10.1590/S1677-04202013005000001","DOIUrl":"https://doi.org/10.1590/S1677-04202013005000001","url":null,"abstract":"Plants growing in temperate regions are often exposed to stress conditions caused by high temperatures. Photosynthesis is one of the metabolic processes most sensitive to high temperature stress, and it is often inhibited before other cellular functions. Using peach leaf disks, we studied the transient chlorophyll a fluorescence along with the gas exchanges at temperatures of 25 (control) 30, 35, 40 and 45°C in the dark for a period of 30 minutes. Temperatures above 35°C caused significant changes in the transient fluorescence of chlorophyll a, including an increase in the initial fluorescence (F0), a decrease in maximum fluorescence values (FM) and the appearance of K and L bands. The values of the net assimilation rate decreased as the temperature increased and reached negative values at 45°C.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81201613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1590/S1677-04202012000400005
D. G. Arias, C. Doria, L. R. Ramos, Heydy Catalina Navia Morocho
Lulo (Solanum quitoense Lam.) is an exotic fruit from the Andes Mountains with a high export potential. However, the browning that is produced during harvest and the postharvest processes alters the organoleptic and nutritional properties of this fruit, which has made its management as a fresh fruit difficult. The browning processes are regulated by the enzyme family of the polyphenol oxidases (PPOs) located in the thylakoids of the chloroplast. When there is damage at the tissue level, the phenolic compounds found in the vacuoles enter into contact with the polyphenol oxidase. This enzyme produces polymerization among the phenolic compounds, as well as between them and the proteins and cell walls. This study analyzed the polyphenol oxidase in lulo var. Castilla at the genetic level, based on DNA and RNA samples. The results showed a high level of homology with other polyphenol oxidases from plants. The highest degree of homology was found with Solanum melongena L., which belongs to the same clade, Leptostemonum. The tyrosinase and two copper-binding domains, characteristic of the polyphenol oxidase, the conserved residues that maintain the natural environment, the sequence of a signal peptide for targeting chloroplast, and the UTRA domain of transcription regulation for recognizing small molecules were identified. Southern blot was used to analyze the number of gene copies, identifying at least eight ones in the lulo genome.
{"title":"Molecular characterization of the polyphenol oxidase gene in lulo (Solanum quitoense Lam.) var. Castilla","authors":"D. G. Arias, C. Doria, L. R. Ramos, Heydy Catalina Navia Morocho","doi":"10.1590/S1677-04202012000400005","DOIUrl":"https://doi.org/10.1590/S1677-04202012000400005","url":null,"abstract":"Lulo (Solanum quitoense Lam.) is an exotic fruit from the Andes Mountains with a high export potential. However, the browning that is produced during harvest and the postharvest processes alters the organoleptic and nutritional properties of this fruit, which has made its management as a fresh fruit difficult. The browning processes are regulated by the enzyme family of the polyphenol oxidases (PPOs) located in the thylakoids of the chloroplast. When there is damage at the tissue level, the phenolic compounds found in the vacuoles enter into contact with the polyphenol oxidase. This enzyme produces polymerization among the phenolic compounds, as well as between them and the proteins and cell walls. This study analyzed the polyphenol oxidase in lulo var. Castilla at the genetic level, based on DNA and RNA samples. The results showed a high level of homology with other polyphenol oxidases from plants. The highest degree of homology was found with Solanum melongena L., which belongs to the same clade, Leptostemonum. The tyrosinase and two copper-binding domains, characteristic of the polyphenol oxidase, the conserved residues that maintain the natural environment, the sequence of a signal peptide for targeting chloroplast, and the UTRA domain of transcription regulation for recognizing small molecules were identified. Southern blot was used to analyze the number of gene copies, identifying at least eight ones in the lulo genome.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74169098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1590/S1677-04202012000400003
M. Karimi, M. H. Asil, H. Zakizadeh
The effects of aminooxyacetic acid, benzyladenine, and 1-methylcyclopropene treatments on the post-production flower quality of potted carnation plants (Dianthus caryophyllus L. Clove Pink) were investigated considering ethylene production and antioxidant metabolism. Maximum plant longevity (17 days) was obtained using 70 ppb of 1-methylcyclopropene. As compared to control plants, ethylene production was significantly decreased by aminooxyacetic acid at concentrations over 100 mg L-1, benzyladenine at 20 or 30 mg L-1, and 1-methylcyclopropene at 70 and 140 ppb. A significant increase in 1-aminocyclopropane-1-carboxylic-acid concentration was observed in 1-methylcyclopropene treated plants compared with the control ones. On the other hand, decline in 1-aminocyclopropane-1-carboxylic-acid concentration was observed after using 100 or 150 mg L-1 of aminooxyacetic acid. Use of 1-methylcyclopropene (70 or 140 ppb), aminooxyacetic acid (100 or 150 mg L-1), and benzyladenine (20 or 30 mg L-1) significantly decreased H2O2 concentration and superoxide radical when compared with the untreated control. Significant increases in activities of superoxide dismutase, catalase, and peroxidase were noticed when plants were treated with 70 ppb 1-methylcyclopropene. In conclusion, aminooxyacetic acid, benzyladenine (at high concentrations), and 1-methylcyclopropene treatments can be suitable candidates for extending plant longevity, maintaining the visual quality, and reducing the loss of flower anthocyanin.
{"title":"Increasing plant longevity and associated metabolic events in potted carnation (Dianthus caryophyllus L. Clove Pink)","authors":"M. Karimi, M. H. Asil, H. Zakizadeh","doi":"10.1590/S1677-04202012000400003","DOIUrl":"https://doi.org/10.1590/S1677-04202012000400003","url":null,"abstract":"The effects of aminooxyacetic acid, benzyladenine, and 1-methylcyclopropene treatments on the post-production flower quality of potted carnation plants (Dianthus caryophyllus L. Clove Pink) were investigated considering ethylene production and antioxidant metabolism. Maximum plant longevity (17 days) was obtained using 70 ppb of 1-methylcyclopropene. As compared to control plants, ethylene production was significantly decreased by aminooxyacetic acid at concentrations over 100 mg L-1, benzyladenine at 20 or 30 mg L-1, and 1-methylcyclopropene at 70 and 140 ppb. A significant increase in 1-aminocyclopropane-1-carboxylic-acid concentration was observed in 1-methylcyclopropene treated plants compared with the control ones. On the other hand, decline in 1-aminocyclopropane-1-carboxylic-acid concentration was observed after using 100 or 150 mg L-1 of aminooxyacetic acid. Use of 1-methylcyclopropene (70 or 140 ppb), aminooxyacetic acid (100 or 150 mg L-1), and benzyladenine (20 or 30 mg L-1) significantly decreased H2O2 concentration and superoxide radical when compared with the untreated control. Significant increases in activities of superoxide dismutase, catalase, and peroxidase were noticed when plants were treated with 70 ppb 1-methylcyclopropene. In conclusion, aminooxyacetic acid, benzyladenine (at high concentrations), and 1-methylcyclopropene treatments can be suitable candidates for extending plant longevity, maintaining the visual quality, and reducing the loss of flower anthocyanin.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84015878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-01DOI: 10.1590/S1677-04202012000400004
Jaqueline Malagutti Corsato, G. Ferreira, C. J. Barbedo
Annona emarginata (Schldtl.) H. Rainer ("araticum-de-terra-fria") is used as a rootstock for several species of Annonaceae. It is suggested that these seeds should be sown immediately after extraction and, therefore, they could be intolerant to desiccation. There are several mechanisms involved with desiccation tolerance. Soluble sugars, for example, can accumulate and act as osmoprotectants for the membrane system during desiccation. The aim of this study is to assess desiccation tolerance in A. emarginata seeds. In addition, we examined the soluble sugars involved in desiccation tolerance. Finally, we determined the effect of gibberellic acid (GA4+7) and N-(phenylmethyl)-aminopurine in promoting the germination of seeds with different water contents. The experiment consisted of a randomized 4x5 factorial design (desiccation levels x concentration of growth regulators). After drying, seeds containing 31 (control), 19, 12 and 5% water were incubated in different concentrations of GA4+7 N-(phenylmethyl)-aminopurine (0, 250, 500, 750 and 1000 mg L-1) for 60 hours. The experiment was conducted in a germination chamber with alternating temperature and photoperiod of 20oC for 18 hours of darkness and 30oC for 6 hours of light. We analyzed electrical conductivity, germination rate, mean germination time, germination speed, frequency and uniformity of germination, percentage of dormant seeds and soluble sugar profile in intact seeds through high-performance liquid chromatography (HPLC). The data were subjected to analysis of variance, and the means were compared using Tukey's test at a threshold of p<0.05. The results showed that seeds of A. emarginata appears to be desiccation tolerant and, also, that sucrose increases when seed water content is reduced to values as low as 12%, exogenous GA4+7+N-(phenylmethyl)-aminopurine improves its germinability.
{"title":"Desiccation tolerance in seeds of Annona emarginata (Schldtl.) H. Rainer and action of plant growth regulators on germination","authors":"Jaqueline Malagutti Corsato, G. Ferreira, C. J. Barbedo","doi":"10.1590/S1677-04202012000400004","DOIUrl":"https://doi.org/10.1590/S1677-04202012000400004","url":null,"abstract":"Annona emarginata (Schldtl.) H. Rainer (\"araticum-de-terra-fria\") is used as a rootstock for several species of Annonaceae. It is suggested that these seeds should be sown immediately after extraction and, therefore, they could be intolerant to desiccation. There are several mechanisms involved with desiccation tolerance. Soluble sugars, for example, can accumulate and act as osmoprotectants for the membrane system during desiccation. The aim of this study is to assess desiccation tolerance in A. emarginata seeds. In addition, we examined the soluble sugars involved in desiccation tolerance. Finally, we determined the effect of gibberellic acid (GA4+7) and N-(phenylmethyl)-aminopurine in promoting the germination of seeds with different water contents. The experiment consisted of a randomized 4x5 factorial design (desiccation levels x concentration of growth regulators). After drying, seeds containing 31 (control), 19, 12 and 5% water were incubated in different concentrations of GA4+7 N-(phenylmethyl)-aminopurine (0, 250, 500, 750 and 1000 mg L-1) for 60 hours. The experiment was conducted in a germination chamber with alternating temperature and photoperiod of 20oC for 18 hours of darkness and 30oC for 6 hours of light. We analyzed electrical conductivity, germination rate, mean germination time, germination speed, frequency and uniformity of germination, percentage of dormant seeds and soluble sugar profile in intact seeds through high-performance liquid chromatography (HPLC). The data were subjected to analysis of variance, and the means were compared using Tukey's test at a threshold of p<0.05. The results showed that seeds of A. emarginata appears to be desiccation tolerant and, also, that sucrose increases when seed water content is reduced to values as low as 12%, exogenous GA4+7+N-(phenylmethyl)-aminopurine improves its germinability.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81689190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-09-01DOI: 10.1590/S1677-04202012000300006
A. Einali, M. Shariati
We studied the effects of n-propyl gallate, which is a plastid terminal oxidase inhibitor involved in chlororespiration, on photosynthesis and physiological parameters in Dunaliella salina grown under different salinities and under low or high irradiance using chlorophyll a fluorescence transient measurements and pigment analysis. The inhibitor up to 1 mM had an additive significant effect on the photosynthetic efficiency in the cell suspensions grown under low salinity and irradiance. However, in the presence of high n-propyl gallate concentration (4 mM), there was a negative effect on all physiological aspects. In contrast, this high concentration of the inhibitor could enhance efficiency of electron transport and growth parameters under high irradiance. On the other hand, with salinity increase, the unfavorable effects of high inhibitor concentration on the efficiency of photosystem II were less evident than of low salinity. Interestingly, n-propyl gallate high concentration had a positive effect on fluorescence and on physiological parameters when high salinities-grown cells were exposed to high irradiance. The results suggest that there is a rational correlation between increase of salinity and algae ability to bypass n-propyl gallate inhibited plastid terminal oxidase function and also direct influence of its lethal concentration on photosystem II compartment. The ability is especially substantial when the increase of salinity is accompanying high irradiance. Furthermore, these data show that algal responses to inhibitor concentrations are different under various environmental conditions.
{"title":"Effects of n-propyl gallate on photosynthesis and physiological parameters in Dunaliella salina are affected by stressful conditions","authors":"A. Einali, M. Shariati","doi":"10.1590/S1677-04202012000300006","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300006","url":null,"abstract":"We studied the effects of n-propyl gallate, which is a plastid terminal oxidase inhibitor involved in chlororespiration, on photosynthesis and physiological parameters in Dunaliella salina grown under different salinities and under low or high irradiance using chlorophyll a fluorescence transient measurements and pigment analysis. The inhibitor up to 1 mM had an additive significant effect on the photosynthetic efficiency in the cell suspensions grown under low salinity and irradiance. However, in the presence of high n-propyl gallate concentration (4 mM), there was a negative effect on all physiological aspects. In contrast, this high concentration of the inhibitor could enhance efficiency of electron transport and growth parameters under high irradiance. On the other hand, with salinity increase, the unfavorable effects of high inhibitor concentration on the efficiency of photosystem II were less evident than of low salinity. Interestingly, n-propyl gallate high concentration had a positive effect on fluorescence and on physiological parameters when high salinities-grown cells were exposed to high irradiance. The results suggest that there is a rational correlation between increase of salinity and algae ability to bypass n-propyl gallate inhibited plastid terminal oxidase function and also direct influence of its lethal concentration on photosystem II compartment. The ability is especially substantial when the increase of salinity is accompanying high irradiance. Furthermore, these data show that algal responses to inhibitor concentrations are different under various environmental conditions.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86801682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-09-01DOI: 10.1590/S1677-04202012000300007
S. Maiti, N. Ghosh, C. Mandal, K. Das, N. Dey, M. K. Adak
Two maize varieties, viz. Sartaj and Deccan, have been evaluated according to their responses to chromium (Cr) in terms of specific physiological and biochemical attributes. During the exposure to Cr concentration (0, 50, 100, 200 and 300 µM) of potassium dichromate (K2Cr2O7) for seven days, significant changes of oxidative stress in terms of lipid peroxidation and protein oxidation were recorded along with other antioxidative pathways. It is revealed that irrespective of varieties, Sartaj was more prone to oxidative stress since the amount of superoxide due to Cr exposure was found to be significant, unlike the second variety, Deccan. In addition, for Sartaj the activity of NAD(P)H oxidase recorded a significant linear increase in a dose response manner.The changes of antioxidative enzymes recorded significant variation in both varieties under stress compared to control. However, Deccan maintains a consistent up regulation in SOD and GPX activities. Contrarily, APX activity was less sensitive to both varieties. The activation of antioxidative mechanisms due to the impact of Cr-induced oxidative stress has been described subsequently. The results deriving from this investigation might be effective for the selection of tolerant plant types under chromium contamination.
{"title":"Responses of the maize plant to chromium stress with reference to antioxidation activity","authors":"S. Maiti, N. Ghosh, C. Mandal, K. Das, N. Dey, M. K. Adak","doi":"10.1590/S1677-04202012000300007","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300007","url":null,"abstract":"Two maize varieties, viz. Sartaj and Deccan, have been evaluated according to their responses to chromium (Cr) in terms of specific physiological and biochemical attributes. During the exposure to Cr concentration (0, 50, 100, 200 and 300 µM) of potassium dichromate (K2Cr2O7) for seven days, significant changes of oxidative stress in terms of lipid peroxidation and protein oxidation were recorded along with other antioxidative pathways. It is revealed that irrespective of varieties, Sartaj was more prone to oxidative stress since the amount of superoxide due to Cr exposure was found to be significant, unlike the second variety, Deccan. In addition, for Sartaj the activity of NAD(P)H oxidase recorded a significant linear increase in a dose response manner.The changes of antioxidative enzymes recorded significant variation in both varieties under stress compared to control. However, Deccan maintains a consistent up regulation in SOD and GPX activities. Contrarily, APX activity was less sensitive to both varieties. The activation of antioxidative mechanisms due to the impact of Cr-induced oxidative stress has been described subsequently. The results deriving from this investigation might be effective for the selection of tolerant plant types under chromium contamination.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83622743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-09-01DOI: 10.1590/S1677-04202012000300009
Carolina M. S. Silva, G. Habermann, M. Marchi, G. Zocolo
Phytohormone analysis using liquid chromatography combined with tandem mass spectrometry is a very important tool for studies involving plant metabolism; however, this analysis can be affected by matrix composition. Although it is necessary to understand this effect to produce reliable results, it has been widely neglected in analyses of plant hormones. Leaf extracts from Bauhinia variegata were obtained by solvent extraction followed by solid-phase cleanup. The extract was analyzed with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in negative ionization mode, using the multiple reaction monitoring mode with two or three transitions to enhance analytical quality control. Although deuterated standards were used as surrogates, pronounced matrix effects were detected for phaseic acid (PA), abscisic acid (ABA) -glycosyl ester (ABA-GE) and dihydrophaseic acid (DPA), whereas ABA, neoPA and 7'-hydroxy-ABA (7'OHABA) showed negligible matrix effects. The method was validated using spiked samples and was applied to monitor ABA, PA, DPA, neoPA, 7´OHABA and ABA-GE on a daily basis. Analyte recoveries from spiked samples ranged from 67% to 87%. The highest leaf concentration of phytohormones was found at 2:00 pm and 5:00 pm, which represent typical day times related to the decrease of stomatal conductance. Despite the use of deuterated phytohormones as internal standards, we showed that the use of a calibration curve constructed with a matrix extract is mandatory for the reliable quantification of ABA and its metabolites, especially PA, ABA-GE and DPA. Daily variations in endogenous ABA leaf concentration were discussed.
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