Pub Date : 2011-01-01DOI: 10.1590/S1677-04202011000100003
Fabrício Bonfim Sudério, Gislainy Karla da Costa Barbosa, E. Gomes-Filho, J. Enéas-Filho
Three β-galactosidase isoforms, β-gal I and β-gal II (cytosolic) and β-gal III (cell wall-associated), were isolated from stems of Vigna unguiculata (L.) Walp. cv. Pitiuba seedlings. Purification consisted of aμMonia sulfate fractionation followed by chromatography in DEAE-Sephadex and Lactosyl-Sepharose columns. The two cytosolic isoforms showed the same chromatography pattern, which differed from that of β-gal III. Electrophoresis revealed a single band of protein for β-gal II and β-gal III which also expressed β-galactosidase activity in gel. The apparent molecular mass of the β-gal I, II and III was 89, 146 and 124 kDa, respectively. The three isoforms revealed the same optimal pH (4.0) and the same optimal assay temperature (55oC) for enzyme activity. The three isoforms were stable at temperatures up to 50oC, and incubation with glucose and galactose expanded their thermal stability as well as inhibited their activities. Galactose was the most effective in promoting these effects and β-gal I and II were competitively inhibited by this sugar. Kinetic analysis using β-PNPG as substrate, revealed KM of 1.69, 1.76 and 1.43 for β-gal I, β-gal II and β-gal III, respectively. The β-gal I was able to hydrolyze all synthetic substrates tested, whereas β-gal II exhibited only β-fucosidase and α-arabinosidase activities, and β-gal III was limited to the α-galactosidase, β-fucosidase and α-arabinosidase activities. These results are consistent with three distinct β-galactosidases exhibiting quite similar kinetic features, but endowed with different functional specificities probably related to their specific roles in the plant cell physiology.
{"title":"Purification and characterization of cytosolic and cell wall β-galactosidases from Vigna unguiculata stems","authors":"Fabrício Bonfim Sudério, Gislainy Karla da Costa Barbosa, E. Gomes-Filho, J. Enéas-Filho","doi":"10.1590/S1677-04202011000100003","DOIUrl":"https://doi.org/10.1590/S1677-04202011000100003","url":null,"abstract":"Three β-galactosidase isoforms, β-gal I and β-gal II (cytosolic) and β-gal III (cell wall-associated), were isolated from stems of Vigna unguiculata (L.) Walp. cv. Pitiuba seedlings. Purification consisted of aμMonia sulfate fractionation followed by chromatography in DEAE-Sephadex and Lactosyl-Sepharose columns. The two cytosolic isoforms showed the same chromatography pattern, which differed from that of β-gal III. Electrophoresis revealed a single band of protein for β-gal II and β-gal III which also expressed β-galactosidase activity in gel. The apparent molecular mass of the β-gal I, II and III was 89, 146 and 124 kDa, respectively. The three isoforms revealed the same optimal pH (4.0) and the same optimal assay temperature (55oC) for enzyme activity. The three isoforms were stable at temperatures up to 50oC, and incubation with glucose and galactose expanded their thermal stability as well as inhibited their activities. Galactose was the most effective in promoting these effects and β-gal I and II were competitively inhibited by this sugar. Kinetic analysis using β-PNPG as substrate, revealed KM of 1.69, 1.76 and 1.43 for β-gal I, β-gal II and β-gal III, respectively. The β-gal I was able to hydrolyze all synthetic substrates tested, whereas β-gal II exhibited only β-fucosidase and α-arabinosidase activities, and β-gal III was limited to the α-galactosidase, β-fucosidase and α-arabinosidase activities. These results are consistent with three distinct β-galactosidases exhibiting quite similar kinetic features, but endowed with different functional specificities probably related to their specific roles in the plant cell physiology.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88565210","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 : 2011-01-01DOI: 10.1590/S1677-04202011000100001
R. Bressan-Smith, A. Façanha
{"title":"In memoriam to Alvim and Maestri","authors":"R. Bressan-Smith, A. Façanha","doi":"10.1590/S1677-04202011000100001","DOIUrl":"https://doi.org/10.1590/S1677-04202011000100001","url":null,"abstract":"","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91493232","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 : 2011-01-01DOI: 10.1590/S1677-04202011000400008
Sara L. Colmenares-Trejos, L. Melgarejo, A. Romero
The physiological response of high Andean forest contrasting plants, Myrcianthes leucoxyla, a shadow-facultative heliophyte, and Abatia parviflora, a heliophyte, was studied during the transition from dry season to wet season in Bogota. Light response curves (A-PAR), water potential (Ψw), transpiration rate (E), stomatal conductance (gs), leaf soluble protein content and peroxidase activity were measured in this study in a 48h cycle. The values for E, gs, Ψw and Ψw predawn for M. leucoxyla were 0.07 to 4.89 µg/cm s, 0.02 to 0.5 cm s-1, -0.025 to -1.05 MPa, and-0.1 MPa, respectively. For A. parviflora E, gs, Ψw and Ψw predawn were 0.47 to 12.27 µg/cm s, 0.17 to 1.42 cm s-1, -0.05 to -0.3 MPa and -0.075 MPa, respectively. A. parviflora presented a tendency of stomatal closure at midday and peroxidase activity increased with the increasing solar radiation, this did not occur in M. leucoxyla. The light compensation point (Ic) in A. parviflora was about 18.10 µmol photon m-2s-1, typical for a heliophyte plant; while for M. leucoxyla it was 8.87 µmol photon m-2s-1, slightly above the maximal reported values for shadow plants and under the minimal reported values for light plants. The lowest photosynthetic rate (A) of M. leucoxyla (2.8 µmol CO2 m-2s-1) in comparison with A. parviflora (7.4 µmol CO2 m-2s-1) is compensated with a better photonic use efficiency (± 0.7792 mol C mol-1).
在波哥大，研究了高安第斯森林对比植物——阴兼性日光植物桃金娘(Myrcianthes leucoxyla)和日光植物小檗(Abatia parviflora)在旱季到雨季过渡期间的生理反应。以48h为周期，测定叶片的光响应曲线(a - par)、水势(Ψw)、蒸腾速率(E)、气孔导度(gs)、叶片可溶性蛋白含量和过氧化物酶活性。黎明前的E、gs、Ψw和Ψw值分别为0.07 ~ 4.89µg/cm s、0.02 ~ 0.5 cm s-1、-0.025 ~ -1.05 MPa和0.1 MPa。雏菊E、gs、Ψw和Ψw在黎明前分别为0.47 ~ 12.27µg/cm s、0.17 ~ 1.42 cm s-1、-0.05 ~ -0.3 MPa和-0.075 MPa。小叶花在正午有气孔关闭的趋势，过氧化物酶活性随太阳辐射的增加而增加，而白桦则没有。小黄花的光补偿点(Ic)约为18.10µmol光子m-2s-1，为典型的日光植物;而白木为8.87µmol光子m-2s-1，略高于遮荫植物的报道最大值，低于光照植物的报道最小值。与parviflora(7.4µmol CO2 m-2s-1)相比，M. leucoxyla(2.8µmol CO2 m-2s-1)的最低光合速率(A)被更好的光子利用效率(±0.7792 mol C mol-1)所补偿。
{"title":"Ecophysiological studies of two andean forest contrasting species Abatia parviflora and Myrcianthes leucoxyla under Bogotá conditions, Colombia","authors":"Sara L. Colmenares-Trejos, L. Melgarejo, A. Romero","doi":"10.1590/S1677-04202011000400008","DOIUrl":"https://doi.org/10.1590/S1677-04202011000400008","url":null,"abstract":"The physiological response of high Andean forest contrasting plants, Myrcianthes leucoxyla, a shadow-facultative heliophyte, and Abatia parviflora, a heliophyte, was studied during the transition from dry season to wet season in Bogota. Light response curves (A-PAR), water potential (Ψw), transpiration rate (E), stomatal conductance (gs), leaf soluble protein content and peroxidase activity were measured in this study in a 48h cycle. The values for E, gs, Ψw and Ψw predawn for M. leucoxyla were 0.07 to 4.89 µg/cm s, 0.02 to 0.5 cm s-1, -0.025 to -1.05 MPa, and-0.1 MPa, respectively. For A. parviflora E, gs, Ψw and Ψw predawn were 0.47 to 12.27 µg/cm s, 0.17 to 1.42 cm s-1, -0.05 to -0.3 MPa and -0.075 MPa, respectively. A. parviflora presented a tendency of stomatal closure at midday and peroxidase activity increased with the increasing solar radiation, this did not occur in M. leucoxyla. The light compensation point (Ic) in A. parviflora was about 18.10 µmol photon m-2s-1, typical for a heliophyte plant; while for M. leucoxyla it was 8.87 µmol photon m-2s-1, slightly above the maximal reported values for shadow plants and under the minimal reported values for light plants. The lowest photosynthetic rate (A) of M. leucoxyla (2.8 µmol CO2 m-2s-1) in comparison with A. parviflora (7.4 µmol CO2 m-2s-1) is compensated with a better photonic use efficiency (± 0.7792 mol C mol-1).","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77148774","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 : 2011-01-01DOI: 10.1590/S1677-04202011000100007
A. Hameed, T. N. Qadri, Mahmooduzzafar, T. O. Siddiqi, M. Iqbal
Cadmium and Mercury induced varying responses in Abelmoschus esculentus L. in relation to enzymes (ascorbate peroxidase (APX, 1.11.1.11), catalase (CAT, 1.11.1.6), glutathione reductase (GR, 1.6.4.2) and superoxide dismutase (SOD, 1.15.1.1) which are most related to the levels of Hg and Cd applied and concentrations of thiol groups already present or induced upon treatment. In the present investigation varying concentrations of CdCl2 and HgCl2 (0, 0.05, 0.10, 0.50, 1 and 2mM respectively) applied to plant in the soil shows a significant increase in ascorbate peroxidase, glutathione reductase and superoxide dismutase activities, and the respective metal accumulation. It reveals a mechanism for constant detoxification of H2O2 that have to be associated with adaptations and ultimate survival of this plant species during stress conditions. A reduction of catalase activities was observed on exposure to these metals, which is supposedly due to the inhibition of enzyme synthesis. Root length, shoot length, number of leaves showed an enhancement with 0.05 mM CdCl2 dose then a gradual decline with the increase in concentrations. The results indicate that A. esculentus is tolerant to high concentrations of these metals, a property related to a differential activation of its enzymatic antioxidant system, and also reveal that this species has a higher capacity of Cd absorption.
镉和汞诱导沙鼠对各种酶(抗坏血酸过氧化物酶(APX, 1.11.1.11)、过氧化氢酶(CAT, 1.11.1.6)、谷胱甘肽还原酶(GR, 1.6.4.2)和超氧化物歧化酶(SOD, 1.15.1.1)产生不同的反应，这些酶与施加的汞和镉水平以及处理后已经存在或诱导的硫基浓度关系最为密切。在本研究中，不同浓度的CdCl2和HgCl2(分别为0、0.05、0.10、0.50、1和2mM)施用于植物土壤中，抗坏血酸过氧化物酶、谷胱甘肽还原酶和超氧化物歧化酶活性显著增加，金属积累量显著增加。它揭示了一种持续解毒H2O2的机制，这种机制与这种植物在逆境条件下的适应和最终生存有关。过氧化氢酶活性的降低被观察到暴露于这些金属，这可能是由于酶合成的抑制。在0.05 mM CdCl2处理下，根长、茎长、叶数均呈增强趋势，但随着浓度的增加，根长、茎长、叶数逐渐下降。结果表明，金盏花对这些高浓度的金属具有耐受性，这一特性与其酶抗氧化系统的差异激活有关，同时也表明金盏花具有更高的Cd吸收能力。
{"title":"Differential activation of the enzymatic antioxidant system of Abelmoschus esculentus L. under CdCl2 and HgCl2 exposure","authors":"A. Hameed, T. N. Qadri, Mahmooduzzafar, T. O. Siddiqi, M. Iqbal","doi":"10.1590/S1677-04202011000100007","DOIUrl":"https://doi.org/10.1590/S1677-04202011000100007","url":null,"abstract":"Cadmium and Mercury induced varying responses in Abelmoschus esculentus L. in relation to enzymes (ascorbate peroxidase (APX, 1.11.1.11), catalase (CAT, 1.11.1.6), glutathione reductase (GR, 1.6.4.2) and superoxide dismutase (SOD, 1.15.1.1) which are most related to the levels of Hg and Cd applied and concentrations of thiol groups already present or induced upon treatment. In the present investigation varying concentrations of CdCl2 and HgCl2 (0, 0.05, 0.10, 0.50, 1 and 2mM respectively) applied to plant in the soil shows a significant increase in ascorbate peroxidase, glutathione reductase and superoxide dismutase activities, and the respective metal accumulation. It reveals a mechanism for constant detoxification of H2O2 that have to be associated with adaptations and ultimate survival of this plant species during stress conditions. A reduction of catalase activities was observed on exposure to these metals, which is supposedly due to the inhibition of enzyme synthesis. Root length, shoot length, number of leaves showed an enhancement with 0.05 mM CdCl2 dose then a gradual decline with the increase in concentrations. The results indicate that A. esculentus is tolerant to high concentrations of these metals, a property related to a differential activation of its enzymatic antioxidant system, and also reveal that this species has a higher capacity of Cd absorption.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72872102","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 : 2011-01-01DOI: 10.1590/S1677-04202011000100006
E. L. Balota, Oswaldo Machineski, Priscila Viviane Truber, A. Scherer, F. S. D. Souza
The physic nut (Jatropha curcas L.) is a perennial tree that occurs naturally in the tropical and subtropical regions of Brazil. Fruits of physic nut present an oil content of 28% on a dry weight basis. Although the plant has adapted to diverse soil conditions such as low fertility, the correction of soil acidity and the addition of fertilizer are essential for highly productive plants. Thus, the response of the physic nut to different soil phosphorus levels (P) and arbuscular mycorrhizal fungi (AMF) inoculation must be characterized. Hence, the objective of the present study was to evaluate the response of physic nut seedlings to arbuscular mycorrhizal fungi (AMF) inoculation at different levels of soil P. Experiment was carried out in a greenhouse encompassing AMF treatments (inoculation with Gigaspora margarita or Glomus clarum, and the non inoculated controls), and phosphorus treatments (0, 25, 50, 100, 200 and 400 mg kg-1 added to soil). At low soil P levels, arbuscular mycorrhizal fungi inoculation had a significant positive effect on plant growth, shoot and root dry matter content, plant height, number of leaves, total leaf area, leaf area per leaf and the Dickson quality index. The root:shoot ratio and the leaf area ratio were also affected by mycorrhizal inoculation and the level of P addition. Physic nut plants exhibited high mycorrhizal dependency at soil P additions up to 50 mg kg-1.
{"title":"Physic nut plants present high mycorrhizal dependency under conditions of low phosphate availability","authors":"E. L. Balota, Oswaldo Machineski, Priscila Viviane Truber, A. Scherer, F. S. D. Souza","doi":"10.1590/S1677-04202011000100006","DOIUrl":"https://doi.org/10.1590/S1677-04202011000100006","url":null,"abstract":"The physic nut (Jatropha curcas L.) is a perennial tree that occurs naturally in the tropical and subtropical regions of Brazil. Fruits of physic nut present an oil content of 28% on a dry weight basis. Although the plant has adapted to diverse soil conditions such as low fertility, the correction of soil acidity and the addition of fertilizer are essential for highly productive plants. Thus, the response of the physic nut to different soil phosphorus levels (P) and arbuscular mycorrhizal fungi (AMF) inoculation must be characterized. Hence, the objective of the present study was to evaluate the response of physic nut seedlings to arbuscular mycorrhizal fungi (AMF) inoculation at different levels of soil P. Experiment was carried out in a greenhouse encompassing AMF treatments (inoculation with Gigaspora margarita or Glomus clarum, and the non inoculated controls), and phosphorus treatments (0, 25, 50, 100, 200 and 400 mg kg-1 added to soil). At low soil P levels, arbuscular mycorrhizal fungi inoculation had a significant positive effect on plant growth, shoot and root dry matter content, plant height, number of leaves, total leaf area, leaf area per leaf and the Dickson quality index. The root:shoot ratio and the leaf area ratio were also affected by mycorrhizal inoculation and the level of P addition. Physic nut plants exhibited high mycorrhizal dependency at soil P additions up to 50 mg kg-1.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75228761","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 : 2011-01-01DOI: 10.1590/S1677-04202011000100009
G. Joshi, A. Shukla, A. Shukla
Jatropha curcas L. is a versatile crop since all its plant material is brought to use either as energy source, industrial or medicinal purpose. Several studies are ongoing in different parts of the world to optimize, enhance and exploit the growth, fruiting cycle and different developmental stages of the plant so that the economic yield of the plants can be utilized to the fullest limits. Foliar application of plant growth regulators such as ethrel (an ethylene releasing compound), indole acetic acid (IAA) and naphthalene acetic acid (NAA) at 50, 100 and 150 ppm, was found to influence different morpho-physiological characters in Jatropha curcas L, such as plant height, collar diameter, tree spread, flower initiation, number of inflorescence per plant, number of male and female flowers per inflorescence, and the ratio of male: female flowers per inflorescence. Moreover, the leaves chlorophyll content, Fv/Fm value, nitrate reductase activity and proline content were also affected by synergistic response of auxin and ethylene. As higher the plant growth regulators concentration higher was the synergic effect on the Jatropha curcas L physiology.
{"title":"Synergistic response of auxin and ethylene on physiology of Jatropha curcas L.","authors":"G. Joshi, A. Shukla, A. Shukla","doi":"10.1590/S1677-04202011000100009","DOIUrl":"https://doi.org/10.1590/S1677-04202011000100009","url":null,"abstract":"Jatropha curcas L. is a versatile crop since all its plant material is brought to use either as energy source, industrial or medicinal purpose. Several studies are ongoing in different parts of the world to optimize, enhance and exploit the growth, fruiting cycle and different developmental stages of the plant so that the economic yield of the plants can be utilized to the fullest limits. Foliar application of plant growth regulators such as ethrel (an ethylene releasing compound), indole acetic acid (IAA) and naphthalene acetic acid (NAA) at 50, 100 and 150 ppm, was found to influence different morpho-physiological characters in Jatropha curcas L, such as plant height, collar diameter, tree spread, flower initiation, number of inflorescence per plant, number of male and female flowers per inflorescence, and the ratio of male: female flowers per inflorescence. Moreover, the leaves chlorophyll content, Fv/Fm value, nitrate reductase activity and proline content were also affected by synergistic response of auxin and ethylene. As higher the plant growth regulators concentration higher was the synergic effect on the Jatropha curcas L physiology.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84234740","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 : 2011-01-01DOI: 10.1590/S1677-04202011000200005
S. Vestena, J. Cambraia, C. Ribeiro, J. Oliveira, M. Oliva
The reactive oxygen species generation, lipid peroxidation and antioxidative enzyme response of water hyacinth and salvinia to Cd were evaluated. Cadmium was absorbed/accumulated mainly in the roots, but significant amounts also translocated to the leaves. No Cd effect on dry weight was detected, although toxicity symptoms were visible. Superoxide and H2O2 concentrations increased, in addition to lipid peroxidation in both species, especially in the leaves of salvinia. In general, antioxidative enzyme activities were reduced in both species following Cd treatment, especially in salvinia. Glutathione peroxidase (GPX, EC 1.11.1.9) activity decreased in water hyacinth but increased in salvinia. Glutathione S-transferase (GST, EC 2.5.1.18) activity increased in the leaves but decreased in the roots of both species. So, Cd induced ROS generation/accumulation, but the antioxidative enzymes were not able to combat the Cd-induced oxidative injury in these two species. Nevertheless, water hyacinth consistently showed a higher tolerance to Cd than salvinia.
{"title":"Cadmium-induced oxidative stress and antioxidative enzyme response in water hyacinth and salvinia","authors":"S. Vestena, J. Cambraia, C. Ribeiro, J. Oliveira, M. Oliva","doi":"10.1590/S1677-04202011000200005","DOIUrl":"https://doi.org/10.1590/S1677-04202011000200005","url":null,"abstract":"The reactive oxygen species generation, lipid peroxidation and antioxidative enzyme response of water hyacinth and salvinia to Cd were evaluated. Cadmium was absorbed/accumulated mainly in the roots, but significant amounts also translocated to the leaves. No Cd effect on dry weight was detected, although toxicity symptoms were visible. Superoxide and H2O2 concentrations increased, in addition to lipid peroxidation in both species, especially in the leaves of salvinia. In general, antioxidative enzyme activities were reduced in both species following Cd treatment, especially in salvinia. Glutathione peroxidase (GPX, EC 1.11.1.9) activity decreased in water hyacinth but increased in salvinia. Glutathione S-transferase (GST, EC 2.5.1.18) activity increased in the leaves but decreased in the roots of both species. So, Cd induced ROS generation/accumulation, but the antioxidative enzymes were not able to combat the Cd-induced oxidative injury in these two species. Nevertheless, water hyacinth consistently showed a higher tolerance to Cd than salvinia.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85593541","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 : 2011-01-01DOI: 10.1590/S1677-04202011000300006
Cibele Tesser da Costa, M. L. Strieder, S. Abel, C. A. Delatorre
Changes in root architecture are an important adaptive strategy used by plants in response to limited nutrient availability to increase the odds of acquiring them. The quiescent center (QC) plays an important role by altering the meristem activity causing differentiation and therefore, inducing a determinate growth program. The arabidopsis mutant pdr23 presents primary short root in the presence of nitrate and is inefficient in the use of nucleic acids as a source of phosphorus. In this study the effect of the pdr23 mutation on the QC maintenance under low phosphorus (P) and/or nitrogen is evaluated. QC identity is maintained in wild-type in the absence of nitrate and/or phosphate if nucleic acids can be used as an alternative source of these nutrients, but not in pdr23. The mutant is not able to use nucleic acids efficiently for substitute Pi, determinate growth is observed, similar to wild-type in the total absence of P. In the absence of N pdr23 loses the expression of QC identity marker earlier than wild-type, indicating that not only the response to P is altered, but also to N. The data suggest that the mutation affects a gene involved either in the crosstalk between these nutrients or in a pathway shared by both nutrients limitation response. Moreover loss of QC identity is also observed in wild-type in the absence of N at longer limitation. Less drastic symptoms are observed in lateral roots of both genotypes.
{"title":"Phosphorus and nitrogen interaction: loss of QC identity in response to P or N limitation is antecipated in pdr23 mutant","authors":"Cibele Tesser da Costa, M. L. Strieder, S. Abel, C. A. Delatorre","doi":"10.1590/S1677-04202011000300006","DOIUrl":"https://doi.org/10.1590/S1677-04202011000300006","url":null,"abstract":"Changes in root architecture are an important adaptive strategy used by plants in response to limited nutrient availability to increase the odds of acquiring them. The quiescent center (QC) plays an important role by altering the meristem activity causing differentiation and therefore, inducing a determinate growth program. The arabidopsis mutant pdr23 presents primary short root in the presence of nitrate and is inefficient in the use of nucleic acids as a source of phosphorus. In this study the effect of the pdr23 mutation on the QC maintenance under low phosphorus (P) and/or nitrogen is evaluated. QC identity is maintained in wild-type in the absence of nitrate and/or phosphate if nucleic acids can be used as an alternative source of these nutrients, but not in pdr23. The mutant is not able to use nucleic acids efficiently for substitute Pi, determinate growth is observed, similar to wild-type in the total absence of P. In the absence of N pdr23 loses the expression of QC identity marker earlier than wild-type, indicating that not only the response to P is altered, but also to N. The data suggest that the mutation affects a gene involved either in the crosstalk between these nutrients or in a pathway shared by both nutrients limitation response. Moreover loss of QC identity is also observed in wild-type in the absence of N at longer limitation. Less drastic symptoms are observed in lateral roots of both genotypes.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87920564","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 : 2011-01-01DOI: 10.1590/S1677-04202011000100002
R. Barros
{"title":"The master and the pupil: two close friends, two great plant physiologists","authors":"R. Barros","doi":"10.1590/S1677-04202011000100002","DOIUrl":"https://doi.org/10.1590/S1677-04202011000100002","url":null,"abstract":"","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80510565","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 : 2011-01-01DOI: 10.1590/S1677-04202011000400001
M. A. Bacarin, S. Deuner, F. V. D. Silva, D. Cassol, Diolina Moura Silva
The effects of salinity stress on chlorophyll fluorescence and the growth of Brassica napus L were investigated. The chlorophyll a fluorescence transient were recorded and analyzed according to the JIP-test which can quantify PSII performance. Salt stress resulted in decreased leaf area and dry matter compared with the control treatment (0 mM NaCl). The most pronounced effects of salt stress were observed with 200 mM NaCl, and the hybrids displayed different levels of sensitivity to stress. The Performance Index (PIABS) was the most sensitive parameter to salt stress, which suggests that this parameter can be used to screen genotypes for salt tolerance.
研究了盐胁迫对甘蓝型油菜叶绿素荧光及生长的影响。根据jip测试记录并分析了叶绿素a荧光瞬态，该测试可以量化PSII的性能。与对照处理(0 mM NaCl)相比，盐胁迫导致叶片面积和干物质减少。以200 mM NaCl处理对盐胁迫的影响最为显著，杂种对盐胁迫表现出不同程度的敏感性。性能指数(PIABS)是对盐胁迫最敏感的参数，可以用来筛选耐盐基因型。
{"title":"Chlorophyll a fluorescence as indicative of the salt stress on Brassica napus L.","authors":"M. A. Bacarin, S. Deuner, F. V. D. Silva, D. Cassol, Diolina Moura Silva","doi":"10.1590/S1677-04202011000400001","DOIUrl":"https://doi.org/10.1590/S1677-04202011000400001","url":null,"abstract":"The effects of salinity stress on chlorophyll fluorescence and the growth of Brassica napus L were investigated. The chlorophyll a fluorescence transient were recorded and analyzed according to the JIP-test which can quantify PSII performance. Salt stress resulted in decreased leaf area and dry matter compared with the control treatment (0 mM NaCl). The most pronounced effects of salt stress were observed with 200 mM NaCl, and the hybrids displayed different levels of sensitivity to stress. The Performance Index (PIABS) was the most sensitive parameter to salt stress, which suggests that this parameter can be used to screen genotypes for salt tolerance.","PeriodicalId":9278,"journal":{"name":"Brazilian Journal of Plant Physiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82156011","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}
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