Pub Date : 2012-09-01DOI: 10.1590/S1677-04202012000300002
Jane Gayalwa Ambede, G. Netondo, G. Mwai, D. Musyimi
The effects of NaCl salinity on seed germination, growth, physiology, and biochemistry of two bambara groundnut landraces (Vigna subterranea (L.) Verdc), Kakamega (white seed coat) and Mumias (red seed coat), were investigated with the aim of establishing traits, which can provide a basis for breeding to salt tolerance in groundnuts. A study was conducted under laboratorial and greenhouse conditions. Bambara groundnut seeds and plants were subjected to five concentrations of NaCl solutions with several electrical conductivities: 0 (control), 6.96, 12.93, 19.89, and 25.86 dS m-1. Germination percentage, growth, chlorophyll fluorescence, and leaf chlorophyll content were determined. Sodium chloride salinity (p 0.05) differences in the Fv/Fm values for Mumias' landrace, as compared to the Control. Overall, Mumias' landrace seeds seemed to be more salt-tolerant at higher salinity levels compared to Kakamega. A greater reduction in growth in Mumias than in Kakamega is a possible indicator for salt tolerance. The chlorophyll fluorescence parameters may not be used to identify salt sensitivity between the two landraces. The results indicated that leaf area and seed germination were suitable parameters for screening the two bambara landraces for salt tolerance.
{"title":"NaCl salinity affects germination, growth, physiology, and biochemistry of bambara groundnut","authors":"Jane Gayalwa Ambede, G. Netondo, G. Mwai, D. Musyimi","doi":"10.1590/S1677-04202012000300002","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300002","url":null,"abstract":"The effects of NaCl salinity on seed germination, growth, physiology, and biochemistry of two bambara groundnut landraces (Vigna subterranea (L.) Verdc), Kakamega (white seed coat) and Mumias (red seed coat), were investigated with the aim of establishing traits, which can provide a basis for breeding to salt tolerance in groundnuts. A study was conducted under laboratorial and greenhouse conditions. Bambara groundnut seeds and plants were subjected to five concentrations of NaCl solutions with several electrical conductivities: 0 (control), 6.96, 12.93, 19.89, and 25.86 dS m-1. Germination percentage, growth, chlorophyll fluorescence, and leaf chlorophyll content were determined. Sodium chloride salinity (p 0.05) differences in the Fv/Fm values for Mumias' landrace, as compared to the Control. Overall, Mumias' landrace seeds seemed to be more salt-tolerant at higher salinity levels compared to Kakamega. A greater reduction in growth in Mumias than in Kakamega is a possible indicator for salt tolerance. The chlorophyll fluorescence parameters may not be used to identify salt sensitivity between the two landraces. The results indicated that leaf area and seed germination were suitable parameters for screening the two bambara landraces for salt tolerance.","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":"83027584","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/S1677-04202012000300003
L. H. G. Mengarda, C. R. Milanez, Diolina Moura Silva, M. A. G. Aguilar, G. Cuzzuol
This study aimed to characterize the alarm and resistance phases of stress of Caesalpinia echinata under intense irradiance in order to better define its position on forest succession. The alarm phase was identified by rapid reduction in the maximum quantum yield of PSII primary photochemical reactions (ΦP0 = FV/FM) and Performance Index (PIABS) followed by total leaf abscission in the first week of exposure to direct sunlight. The new leaves grown showed recovery of chlorophyll a parameters, increase in blade thickness, elongation of the palisade and spongy parenchymas, higher water content, and reduction of specific leaf area. These changes were associated with the osmoprotector of sucrose and antioxidative of raffinose effects, which indicate an efficient adjustment system to intense irradiance in the resistance phase of stress. However, the continuous decrease in photosynthetic pigments in the resistance phase combined with the photodamage in the fluorescence of Chl a and total abscission of leaves in the alarm phase are strong indications that C. echinata is a shade and late or climax species in forest succession.
{"title":"Morphological and physiological adjustments of Brazilwood (Caesalpinia echinata Lam.) to direct solar radiation","authors":"L. H. G. Mengarda, C. R. Milanez, Diolina Moura Silva, M. A. G. Aguilar, G. Cuzzuol","doi":"10.1590/S1677-04202012000300003","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300003","url":null,"abstract":"This study aimed to characterize the alarm and resistance phases of stress of Caesalpinia echinata under intense irradiance in order to better define its position on forest succession. The alarm phase was identified by rapid reduction in the maximum quantum yield of PSII primary photochemical reactions (ΦP0 = FV/FM) and Performance Index (PIABS) followed by total leaf abscission in the first week of exposure to direct sunlight. The new leaves grown showed recovery of chlorophyll a parameters, increase in blade thickness, elongation of the palisade and spongy parenchymas, higher water content, and reduction of specific leaf area. These changes were associated with the osmoprotector of sucrose and antioxidative of raffinose effects, which indicate an efficient adjustment system to intense irradiance in the resistance phase of stress. However, the continuous decrease in photosynthetic pigments in the resistance phase combined with the photodamage in the fluorescence of Chl a and total abscission of leaves in the alarm phase are strong indications that C. echinata is a shade and late or climax species in forest succession.","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":"85927873","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/S1677-04202012000300004
G. C. Pathak, B. Gupta, N. Pandey
Zinc deficiency is not only the cause of low productivity of crops, but it also results in low zinc content in seeds, which leads to poor dietary zinc intake. To study the effect of zinc foliar application on improving plant yield and seed zinc content for human consumption, chickpea plants were raised in refined sand culture with deficient (0.2 µM) and sufficient (1µM) supply of zinc under glass-house conditions. Prior to initiation of the reproductive phase, zinc was applied as 0.1% ZnSO4 foliar spray to both zinc sufficient and deficient plants. The plants exposed to different zinc treatments were studied for pollen and stigma structure and their involvement in fertilization and seed yield. Zinc deficiency induces flower abortion, pollen, and ovule infertility leading to low seed set and ultimately its yield. Foliar application of ZnSO4 to zinc deficient plants at the time of initiation of flowering partially reverses the adverse effect of zinc deficiency on pollen-stigma morphology, pollen fertility, and greatly enhanced seed yield of plants. Zinc foliar application improved not only the boldness and vigor of seeds in zinc-deficient plants, but also the seed zinc content in zinc-deficient seeds as well as the sufficient ones.
{"title":"Improving reproductive efficiency of chickpea by foliar application of zinc","authors":"G. C. Pathak, B. Gupta, N. Pandey","doi":"10.1590/S1677-04202012000300004","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300004","url":null,"abstract":"Zinc deficiency is not only the cause of low productivity of crops, but it also results in low zinc content in seeds, which leads to poor dietary zinc intake. To study the effect of zinc foliar application on improving plant yield and seed zinc content for human consumption, chickpea plants were raised in refined sand culture with deficient (0.2 µM) and sufficient (1µM) supply of zinc under glass-house conditions. Prior to initiation of the reproductive phase, zinc was applied as 0.1% ZnSO4 foliar spray to both zinc sufficient and deficient plants. The plants exposed to different zinc treatments were studied for pollen and stigma structure and their involvement in fertilization and seed yield. Zinc deficiency induces flower abortion, pollen, and ovule infertility leading to low seed set and ultimately its yield. Foliar application of ZnSO4 to zinc deficient plants at the time of initiation of flowering partially reverses the adverse effect of zinc deficiency on pollen-stigma morphology, pollen fertility, and greatly enhanced seed yield of plants. Zinc foliar application improved not only the boldness and vigor of seeds in zinc-deficient plants, but also the seed zinc content in zinc-deficient seeds as well as the sufficient ones.","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":"83735563","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/S1677-04202012000300005
D. Medeiros, Elizamar Ciríaco da Silva, H. Santos, Cinthya Mirella Pacheco, R. S. Musser, Rejane M. Nogueira
To evaluate physiological genotypic differences between two Barbados cherry genotypes (13- and 14-CPA) under water deficit, initial growth, water relations, and organic solute accumulation were evaluated in an experiment performed using four-month-old seedlings, which were subjected to four water treatments (100, 75, 50, and 25% of field capacity), with five replications. Severe water deficit (25% of field capacity) negatively affected plant height, stem diameter, leaf area, dry matter of the leaves and stem to both genotypes, and root dry matter to genotype 13-CPA. Predawn (Ywpd) and midday leaf water potentials (Ywmd) were reduced in plants grown under 25% of field capacity, only in the genotype 14-CPA. There was not a change in relative water content, even with the reduction in the leaf water potential. Severe water deficit did not induce organic solutes accumulation, instead it reduced carbohydrate content in leaves of genotypes and aminoacids, proline and proteins, in genotype 13-CPA. In the roots accumulation of all organic solutes studied, it was verified genotype 13-CPA under 25% of field capacity, but only carbohydrates increased in plants under 25% of field capacity to 14-CPA. These results suggest two different mechanisms used by Barbados cherry genotypes to maintain the water status. To the 13-CPA one, the accumulation of soluble organic solutes in the roots is the main mechanism used to maintain the tissue hydration. However, the 14-CPA genotype changed the root to shoot ratio in order to avoid desiccation. Despite the mechanism used by both genotypes, a moderate drought stress does not induce significant morphophysiological changes in Barbados cherry.
{"title":"Physiological and biochemical responses to drought stress in Barbados cherry","authors":"D. Medeiros, Elizamar Ciríaco da Silva, H. Santos, Cinthya Mirella Pacheco, R. S. Musser, Rejane M. Nogueira","doi":"10.1590/S1677-04202012000300005","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300005","url":null,"abstract":"To evaluate physiological genotypic differences between two Barbados cherry genotypes (13- and 14-CPA) under water deficit, initial growth, water relations, and organic solute accumulation were evaluated in an experiment performed using four-month-old seedlings, which were subjected to four water treatments (100, 75, 50, and 25% of field capacity), with five replications. Severe water deficit (25% of field capacity) negatively affected plant height, stem diameter, leaf area, dry matter of the leaves and stem to both genotypes, and root dry matter to genotype 13-CPA. Predawn (Ywpd) and midday leaf water potentials (Ywmd) were reduced in plants grown under 25% of field capacity, only in the genotype 14-CPA. There was not a change in relative water content, even with the reduction in the leaf water potential. Severe water deficit did not induce organic solutes accumulation, instead it reduced carbohydrate content in leaves of genotypes and aminoacids, proline and proteins, in genotype 13-CPA. In the roots accumulation of all organic solutes studied, it was verified genotype 13-CPA under 25% of field capacity, but only carbohydrates increased in plants under 25% of field capacity to 14-CPA. These results suggest two different mechanisms used by Barbados cherry genotypes to maintain the water status. To the 13-CPA one, the accumulation of soluble organic solutes in the roots is the main mechanism used to maintain the tissue hydration. However, the 14-CPA genotype changed the root to shoot ratio in order to avoid desiccation. Despite the mechanism used by both genotypes, a moderate drought stress does not induce significant morphophysiological changes in Barbados cherry.","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":"82903173","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/S1677-04202012000300008
Armando González, W. Tezara, E. Rengifo, A. Herrera
Nicotiana glauca, a shrub native to southern South America, is widely distributed in the Americas, from Patagonia to the USA, from zero up to 3,700 m; it rapidly invades disturbed environments. In Venezuela, it has been reported from zero up to 2,000 m growing in contrasting conditions of relative humidity, temperature, rainfall, and salinity. In order to gain insight into the extent and mode of resistance to drought and salinity in N. glauca, we studied the effect of these factors on water relations and photosynthesis under both natural and greenhouse conditions. In the field, water potential, photosynthetic rate (A) and stomatal conductance (gs), but not relative water content (RWC) decreased because of drought. Manual removal of epicuticular wax increased excess energy dissipation through non-photochemical quenching without altering the capacity of photochemical quenching. In the greenhouse, water deficit as well as salinity resulted in osmotic adjustment; at the end of the experiment, turgor potential and RWC under water deficit were similar to control and higher under salinity. Water deficit and salinity caused marked decreases in A and gs. There were very few or no changes with natural drought, salinity or experimental water deficit in potential quantum efficiency of PSII, which could be explained partly by an increased non-photochemical quenching. We conclude that the partial tolerance to drought and salinity in plants of N. glauca resides in their ability to achieve water conservation through stomatal closure and osmotic adjustment, reduce absorption of excess radiation through the presence of leaf wax and dissipate it through increased non-photochemical quenching. All these characteristics confer plants of N. glauca advantages to invade disturbed areas, subject to salinity and/or seasonal drought under high irradiance.
{"title":"Ecophysiological responses to drought and salinity in the cosmopolitan invader Nicotiana glauca.","authors":"Armando González, W. Tezara, E. Rengifo, A. Herrera","doi":"10.1590/S1677-04202012000300008","DOIUrl":"https://doi.org/10.1590/S1677-04202012000300008","url":null,"abstract":"Nicotiana glauca, a shrub native to southern South America, is widely distributed in the Americas, from Patagonia to the USA, from zero up to 3,700 m; it rapidly invades disturbed environments. In Venezuela, it has been reported from zero up to 2,000 m growing in contrasting conditions of relative humidity, temperature, rainfall, and salinity. In order to gain insight into the extent and mode of resistance to drought and salinity in N. glauca, we studied the effect of these factors on water relations and photosynthesis under both natural and greenhouse conditions. In the field, water potential, photosynthetic rate (A) and stomatal conductance (gs), but not relative water content (RWC) decreased because of drought. Manual removal of epicuticular wax increased excess energy dissipation through non-photochemical quenching without altering the capacity of photochemical quenching. In the greenhouse, water deficit as well as salinity resulted in osmotic adjustment; at the end of the experiment, turgor potential and RWC under water deficit were similar to control and higher under salinity. Water deficit and salinity caused marked decreases in A and gs. There were very few or no changes with natural drought, salinity or experimental water deficit in potential quantum efficiency of PSII, which could be explained partly by an increased non-photochemical quenching. We conclude that the partial tolerance to drought and salinity in plants of N. glauca resides in their ability to achieve water conservation through stomatal closure and osmotic adjustment, reduce absorption of excess radiation through the presence of leaf wax and dissipate it through increased non-photochemical quenching. All these characteristics confer plants of N. glauca advantages to invade disturbed areas, subject to salinity and/or seasonal drought under high irradiance.","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":"83172761","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 : 2012-06-01DOI: 10.1590/S1677-04202012000200005
U. Chakraborty, B. Pradhan
Five varieties of wheat (Triticum aestivum L.) - KW, UP 2752, PBW 343, SO and LV - were subjected to water stress and sampling was done on the 3rd, 6th and 9th day of stress. RWC decline in KW, UP 2752 and PBW 343 (36.65, 42.34 and 40.75% respectively) was comparatively lesser than in LV and SO (52.93 and 52.67% respectively). In all varieties tested, three antioxidant enzymes (POX, APOX and GR) showed an initial increase. The activity of POX and GR increased with the increase in the duration of stress in KW, UP 2752 and PBW 343, while the activity of APOX declined. However, CAT and SOD showed an initial increase in these varieties, whereas it declined in SO and LV with increase in the period of stress. Accumulation of H2O2 declined during prolonged water stress in KW, UP 2752 and PBW 343, while it increased in LV and SO. The accumulation of MDA content was three times higher in susceptible varieties than in tolerant varieties. The content of proline, phenol and ascorbate increased during water stress whereas the accumulation of carotenoid showed a significant decrease after showing an initial increase in the tested varieties. Higher values of total antioxidant and MSI were recorded in KW, UP 2752 and PBW 343 during stress while after 6 days MSI declined in LV and SO. During water stress there was a general decline in the total chlorophyll content. Analyzing the data, the present work suggested that out of the five varieties, KW, UP 2752 and PBW 343 showed more tolerance to water stress than SO and LV.
{"title":"Oxidative stress in five wheat varieties (Triticum aestivum L.) exposed to water stress and study of their antioxidant enzyme defense system, water stress responsive metabolites and H2O2 accumulation","authors":"U. Chakraborty, B. Pradhan","doi":"10.1590/S1677-04202012000200005","DOIUrl":"https://doi.org/10.1590/S1677-04202012000200005","url":null,"abstract":"Five varieties of wheat (Triticum aestivum L.) - KW, UP 2752, PBW 343, SO and LV - were subjected to water stress and sampling was done on the 3rd, 6th and 9th day of stress. RWC decline in KW, UP 2752 and PBW 343 (36.65, 42.34 and 40.75% respectively) was comparatively lesser than in LV and SO (52.93 and 52.67% respectively). In all varieties tested, three antioxidant enzymes (POX, APOX and GR) showed an initial increase. The activity of POX and GR increased with the increase in the duration of stress in KW, UP 2752 and PBW 343, while the activity of APOX declined. However, CAT and SOD showed an initial increase in these varieties, whereas it declined in SO and LV with increase in the period of stress. Accumulation of H2O2 declined during prolonged water stress in KW, UP 2752 and PBW 343, while it increased in LV and SO. The accumulation of MDA content was three times higher in susceptible varieties than in tolerant varieties. The content of proline, phenol and ascorbate increased during water stress whereas the accumulation of carotenoid showed a significant decrease after showing an initial increase in the tested varieties. Higher values of total antioxidant and MSI were recorded in KW, UP 2752 and PBW 343 during stress while after 6 days MSI declined in LV and SO. During water stress there was a general decline in the total chlorophyll content. Analyzing the data, the present work suggested that out of the five varieties, KW, UP 2752 and PBW 343 showed more tolerance to water stress than SO and LV.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74200400","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 : 2012-06-01DOI: 10.1590/S1677-04202012000200003
Frederico Lage-Pinto, E. Bernini, J. G. Oliveira, A. P. Vitória
Gas exchange, chlorophyll afluorescence, and photosynthetic pigments of Xylopia sericeaA. St.-Hil. and Siparuna guianensis Aubl. were evaluated during the rainy season and the dry season (2009-2010) in three understories with different ecological conditions (irradiance, water availability, and temperature) located in the Uniao Biological Reserve (known as REBIO Uniao), at Rio de Janeiro State, a natural forest understory, eucalyptus understory under regeneration, and understory of eucalyptus plantation with 18-year-old trees that were removed 1 year before. The lowest values of Fv/Fme Fm/Fowere observed in the exposed understory for both seasons, with lower values in the dry season, suggesting that reduced water availability potentializes the photoinhibitory process. For both species of the exposed understory it is suggested the occurrence of photoprotection, given that an increased proportion of carotenoid pigments in relation to the chlorophylls were verified. Both species still exhibited dynamic photoinhibition after 1 year of exposure to full sunlight (exposed understory) in both seasons, but more markedly so in the dry season, though they belong to early stages of ecological succession. Based on the results, it is suggested that these species are indicated for planting in degraded areas and that the cutting of eucalyptus trees as management practice should be performed in a gradual manner, during the rainy season, in order to minimize stress on these species.
{"title":"Photosynthetic analyses of two native Atlantic Forest species in regenerative understory of eucalyptus plantation","authors":"Frederico Lage-Pinto, E. Bernini, J. G. Oliveira, A. P. Vitória","doi":"10.1590/S1677-04202012000200003","DOIUrl":"https://doi.org/10.1590/S1677-04202012000200003","url":null,"abstract":"Gas exchange, chlorophyll afluorescence, and photosynthetic pigments of Xylopia sericeaA. St.-Hil. and Siparuna guianensis Aubl. were evaluated during the rainy season and the dry season (2009-2010) in three understories with different ecological conditions (irradiance, water availability, and temperature) located in the Uniao Biological Reserve (known as REBIO Uniao), at Rio de Janeiro State, a natural forest understory, eucalyptus understory under regeneration, and understory of eucalyptus plantation with 18-year-old trees that were removed 1 year before. The lowest values of Fv/Fme Fm/Fowere observed in the exposed understory for both seasons, with lower values in the dry season, suggesting that reduced water availability potentializes the photoinhibitory process. For both species of the exposed understory it is suggested the occurrence of photoprotection, given that an increased proportion of carotenoid pigments in relation to the chlorophylls were verified. Both species still exhibited dynamic photoinhibition after 1 year of exposure to full sunlight (exposed understory) in both seasons, but more markedly so in the dry season, though they belong to early stages of ecological succession. Based on the results, it is suggested that these species are indicated for planting in degraded areas and that the cutting of eucalyptus trees as management practice should be performed in a gradual manner, during the rainy season, in order to minimize stress on these species.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79855825","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 : 2012-06-01DOI: 10.1590/S1677-04202012000200006
Fernanda da Silva Alabarce, L. R. Dillenburg
The role of seed reserves on the ability to resprout and on the responses of resprouting in Araucaria angustifoliawas investigated. Seedlings were separated into three groups: plants which had their shoot damaged, a similar group in which damaged plants had their connection to the supporting seed removed, and a control group. All damaged seedlings resprouted, but those which remained connected to their seeds had a greater mass of resprouted shoots than the ones disconnected from their seeds. A greater accumulation of seed mass in the underground hypocotyl was a very distinct initial response to damage, but, on the long run, damaged plants were able to reestablish a biomass allocation pattern, which was very similar to the control plants. These results indicate that seed and underground reserves are important for the quantitative resprouting response of seedlings of Aangustifolia and for its ability to reestablish the functional balance when severely damaged.
{"title":"Resprouting ability and intensity after damage in seedlings of the large-seeded species Araucaria angustifolia","authors":"Fernanda da Silva Alabarce, L. R. Dillenburg","doi":"10.1590/S1677-04202012000200006","DOIUrl":"https://doi.org/10.1590/S1677-04202012000200006","url":null,"abstract":"The role of seed reserves on the ability to resprout and on the responses of resprouting in Araucaria angustifoliawas investigated. Seedlings were separated into three groups: plants which had their shoot damaged, a similar group in which damaged plants had their connection to the supporting seed removed, and a control group. All damaged seedlings resprouted, but those which remained connected to their seeds had a greater mass of resprouted shoots than the ones disconnected from their seeds. A greater accumulation of seed mass in the underground hypocotyl was a very distinct initial response to damage, but, on the long run, damaged plants were able to reestablish a biomass allocation pattern, which was very similar to the control plants. These results indicate that seed and underground reserves are important for the quantitative resprouting response of seedlings of Aangustifolia and for its ability to reestablish the functional balance when severely damaged.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84599923","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 : 2012-06-01DOI: 10.1590/S1677-04202012000200001
Â. Dalmolin, H. Dalmagro, F. Lobo, Mário Zortéa Antunes Júnior, C. Ortíz, G. Vourlitis
Vochysia divergens Pohl (commonly known as cambara) is a pioneer tree species that is native to the Amazon Basin but has been invading the seasonally flooded wetlands of the Brazilian Pantanal, forming monospecific communities. The physiological aspects associated with cambara invasion, including the effects of flooding and shading on growth and leaf gas exchange, are unknown but may shed light on why cambara is able to invade this novel habitat so rapidly. Thus, we conducted a manipulative experiment to quantify the effects of shading and flooding on the growth, gas exchange and leaf nutrient content of V. divergens saplings. Based on previous research we hypothesized that (1) experimental flooding would have no effect on the growth and gas exchange of V. divergens,and (2) experimental shading would reduce the growth and gas exchange of V. divergens regardless of the water treatment plants are subjected. Our data indicate that shading significantly increased the height, stomatal conductance (gs), and transpiration (T) of V. divergens saplings, especially for plants exposed to normal irrigation. Experimental flooding significantly reduced rates of leaf production, plant height, and gas exchange; however, shaded plants exposed to flooding had a higher water use efficiency than plants exposed to full sun and flooding, because Twas more depressed than net photosynthesis (A) in flooded plants exposed to full sun. Despite the inhibitory effects of flooding and shading, V. divergenssaplings exhibited positive growth and C gain, regardless of the growth light environment or water level, indicating that the growth and leaf gas exchange of species is tolerant to both flooding and shading. Such tolerance to a wide variety of hydrological and growth light conditions presumably explains the ability of cambara to invade, and ultimately form dense, monospecific stands in the Brazilian Pantanal.
{"title":"Effects of flooding and shading on growth and gas exchange of Vochysia divergens Pohl (Vochysiaceae) of invasive species in the Brazilian Pantanal","authors":"Â. Dalmolin, H. Dalmagro, F. Lobo, Mário Zortéa Antunes Júnior, C. Ortíz, G. Vourlitis","doi":"10.1590/S1677-04202012000200001","DOIUrl":"https://doi.org/10.1590/S1677-04202012000200001","url":null,"abstract":"Vochysia divergens Pohl (commonly known as cambara) is a pioneer tree species that is native to the Amazon Basin but has been invading the seasonally flooded wetlands of the Brazilian Pantanal, forming monospecific communities. The physiological aspects associated with cambara invasion, including the effects of flooding and shading on growth and leaf gas exchange, are unknown but may shed light on why cambara is able to invade this novel habitat so rapidly. Thus, we conducted a manipulative experiment to quantify the effects of shading and flooding on the growth, gas exchange and leaf nutrient content of V. divergens saplings. Based on previous research we hypothesized that (1) experimental flooding would have no effect on the growth and gas exchange of V. divergens,and (2) experimental shading would reduce the growth and gas exchange of V. divergens regardless of the water treatment plants are subjected. Our data indicate that shading significantly increased the height, stomatal conductance (gs), and transpiration (T) of V. divergens saplings, especially for plants exposed to normal irrigation. Experimental flooding significantly reduced rates of leaf production, plant height, and gas exchange; however, shaded plants exposed to flooding had a higher water use efficiency than plants exposed to full sun and flooding, because Twas more depressed than net photosynthesis (A) in flooded plants exposed to full sun. Despite the inhibitory effects of flooding and shading, V. divergenssaplings exhibited positive growth and C gain, regardless of the growth light environment or water level, indicating that the growth and leaf gas exchange of species is tolerant to both flooding and shading. Such tolerance to a wide variety of hydrological and growth light conditions presumably explains the ability of cambara to invade, and ultimately form dense, monospecific stands in the Brazilian Pantanal.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89319959","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 : 2012-06-01DOI: 10.1590/S1677-04202012000200004
C. Ribeiro, J. Cambraia, P. H. P. Peixoto, É. M. F. Júnior
The antioxidant defense system response was evaluated in two rice cultivars (Oryza sativa L.), Fernandes (CNA-1158) and Maravilha (CNA-6843-1), treated with toxic levels of aluminum. After exposure to aluminum we determined plant growth, H2O2 and O2•- contents, lipid peroxidation, antioxidant enzymes activities and ascorbate and dehydroascorbate contents. Al predominantly accumulated in roots of both cultivars but it reduced root and shoot growth only in the Maravilha cultivar. Treatment with aluminum resulted in a reduction of 84 and 60% in the levels of H2O2 in the roots of the cultivars Maravilha and Fernandes, respectively, and of 26% in the levels of O2•- only in the roots of Fernandes cultivar. Increased lipid peroxidation was observed only in the roots of the Maravilha cultivar. In general, the antioxidant enzyme activities were higher in roots and increased in the presence of aluminum, especially in the Fernandes cultivar. The levels of ascorbate were higher in leaves and increased with aluminum treatment, while dehydroascorbate decreased in roots of both cultivars after aluminum treatment. However, the ascorbate/dehydroascorbate ratio increased in the roots of both cultivars after treatment with aluminum. Ascorbate, dehydroascorbate and ascorbate/dehydroascorbate levels found here point to an efficient regeneration of ascorbate, essential for the homeostasis of cellular metabolites involved in reactive oxygen species removal by rice plants treated with aluminum. Therefore, the higher tolerance of Fernandes to aluminum relative to Maravilha cultivar may be the result of better growth of the root system and shoots, higher antioxidant enzyme activities and a best use/regeneration of ascorbate.
{"title":"Antioxidant system response induced by aluminum in two rice cultivars","authors":"C. Ribeiro, J. Cambraia, P. H. P. Peixoto, É. M. F. Júnior","doi":"10.1590/S1677-04202012000200004","DOIUrl":"https://doi.org/10.1590/S1677-04202012000200004","url":null,"abstract":"The antioxidant defense system response was evaluated in two rice cultivars (Oryza sativa L.), Fernandes (CNA-1158) and Maravilha (CNA-6843-1), treated with toxic levels of aluminum. After exposure to aluminum we determined plant growth, H2O2 and O2•- contents, lipid peroxidation, antioxidant enzymes activities and ascorbate and dehydroascorbate contents. Al predominantly accumulated in roots of both cultivars but it reduced root and shoot growth only in the Maravilha cultivar. Treatment with aluminum resulted in a reduction of 84 and 60% in the levels of H2O2 in the roots of the cultivars Maravilha and Fernandes, respectively, and of 26% in the levels of O2•- only in the roots of Fernandes cultivar. Increased lipid peroxidation was observed only in the roots of the Maravilha cultivar. In general, the antioxidant enzyme activities were higher in roots and increased in the presence of aluminum, especially in the Fernandes cultivar. The levels of ascorbate were higher in leaves and increased with aluminum treatment, while dehydroascorbate decreased in roots of both cultivars after aluminum treatment. However, the ascorbate/dehydroascorbate ratio increased in the roots of both cultivars after treatment with aluminum. Ascorbate, dehydroascorbate and ascorbate/dehydroascorbate levels found here point to an efficient regeneration of ascorbate, essential for the homeostasis of cellular metabolites involved in reactive oxygen species removal by rice plants treated with aluminum. Therefore, the higher tolerance of Fernandes to aluminum relative to Maravilha cultivar may be the result of better growth of the root system and shoots, higher antioxidant enzyme activities and a best use/regeneration of ascorbate.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88648325","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：