Rams exhibiting relatively high levels of sexual performance (HP) repeat-breed the same female fe... more Rams exhibiting relatively high levels of sexual performance (HP) repeat-breed the same female fewer times than low-performing (LP) rams. The objective of this study was to determine if HP and LP bulls differed in their tendency to repeat-breed individual females. Eighteen sexually experienced Angus bulls (20±60 months of age) were tested individually with 10 unrestrained, estrous females. The sexual behaviors of all cattle were recorded until the bull achieved six services (ejaculations). Bulls were tested on 2 days with at least 10 days between tests. Frequencies of recorded sexual behaviors were higher for LP than HP bulls (P < 0:05), possibly because of the greater time spent in attaining six services. LP and HP bulls did not differ in the number of females serviced. LP bulls serviced the same number of individual females in both tests (4:0 AE 0:3). However, HP bulls serviced a greater number of individual females (repeat-bred less) during Test 2 than Test 1 (4:7 AE 0:3 and 3:0 AE 0:3; P < 0:05). There was no correlation between time to attain six services and the number of different females serviced (r 0:04), but the number of different females serviced positively correlated with age of the bull (r 0:53, P < 0:05). Repeat-breeding of at least one female was observed in 33 of 36 tests (92%). Repeat-breeding at least one female twice in succession was observed in 24 of 36 tests (67%). There were 12 of 36 tests (33%) in which a female was serviced twice but not in succession. Females were serviced three times in succession in seven tests (19.4%). Sexual performance level did not in¯uence mate preferences or the incidence of repeat-breeding during tests. #
O lodo de esgoto obtido do tratamento das águas servidas contém considerável percentual de matéri... more O lodo de esgoto obtido do tratamento das águas servidas contém considerável percentual de matéria orgânica e de elementos essenciais para as plantas, podendo desempenhar importante papel na produção agrícola e na manutenção da fertilidade do solo. O presente trabalho objetivou estudar o efeito da aplicação de doses crescentes de lodo produzido pela Companhia Pernambucana de Saneamento (COMPESA) sobre as características químicas de dois solos, quantidades de metais pesados absorvidas e crescimento de plantas de milho e de feijoeiro cultivadas em casa de vegetação, visando à futura utilização do lodo em ensaios de campo. Foram utilizados dois tipos de solos com diferentes teores de argila aos quais foram adicionadas seis doses de lodo de esgoto (equivalentes a 0, 10, 20, 30, 40 e 60 Mg ha-1). As aplicações promoveram diminuição do pH e aumento dos teores de matéria orgânica, nitrogênio total, fósforo, potássio, sódio, cálcio e magnésio em ambos os solos, exceção feita aos teores de sódio e potássio de um deles. As doses de lodo de esgoto aumentaram a produção de matéria seca do milho e do feijoeiro. Os teores dos metais Zn, Cu, Mn, Fe e Pb no lodo, no solo e nas plantas estiveram abaixo dos limites estabelecidos para utilização agrícola, o que permite sua aplicação sem maiores riscos ao ambiente.
Although silicon (Si) is not an essential element, it presents a close relationship with the alle... more Although silicon (Si) is not an essential element, it presents a close relationship with the alleviation of heavy-metal toxicity to plants. This work was carried out to evaluate the effects of Si application to soil on the amelioration of metal stress to maize grown on a contaminated soil amended with Si (0, 50, 100, 150, and 200 mg kg–1) as calcium silicate (CaSiO3). Additionally, the cadmium (Cd) and zinc (Zn) bioavailability as well as their distribution into soil fractions was also studied. The results showed that adding Si to a Cd- and Zn-contaminated soil effectively diminished the metal stress and resulted in biomass increase in comparison to metal-contaminated soil not treated with Si. This relied on Cd and Zn immobilization in soil rather than on the increase of soil pH driven by calcium silicate application. Silicon altered the Cd and Zn distribution in soil fractions, decreasing the most bioavailable pools and increasing the allocation of metals into more stable fractions such as organic matter and crystalline iron oxides.
Silicon presents a close relationship with the amelioration of heavy metals phytotoxicity. Howeve... more Silicon presents a close relationship with the amelioration of heavy metals phytotoxicity. However, mechanisms of Si-mediated alleviation of metal stress remains poorly understood. This work aimed at studying the relationship between the accumulation of Si, Cd, and Zn and the tolerance and structural alterations displayed by maize plants grown on a Cd and Zn enriched soil treated with doses of Si (0, 50, 100, 150, and 200mg kg−1) as calcium silicate (CaSiO3). The results showed that the maize plants treated with Si presented not only biomass increasing but also higher metal accumulation. Significant structural alterations on xylem diameter, mesophyll and epidermis thickness, and transversal area occupied by collenchyma and midvein were also observed as a result of Si application. The deposition of silica in the endodermis and pericycle of roots seems to play an important role on the maize tolerance to Cd and Zn stress.
Phytoextraction has emerged as a novel approach to clean up metal-polluted soils in which plants ... more Phytoextraction has emerged as a novel approach to clean up metal-polluted soils in which plants are used to transfer toxic metals from soils to shoots. This review provides a synthesis of current knowledge on phytoextraction of metals from soils and their accumulation in plants. The objective is to integrate soil-related (root exudates and chemical amendments) and biological advances to suggest research needs and future directions. As far as can be deduced from the literature, it will be some time before phytoextraction may be established as a commercial technology. For chemically-assisted phytoextraction, research has not shown easily biodegradable compounds to overcome the risks associated with the use of EDTA for poorly available metals in soils. On the other hand, significant progress has been made on the physiological and molecular aspects regarding tolerance and phytoaccumulation of metals in plants. A multidisciplinary approach is warranted to make phytoextraction a feasible commercial technology to remediate metal-polluted soils.
Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy met... more Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy metals that can contaminate the soil and threat the health of animals and humans. The present study focused the determination of Cd and Pb concentrations in different phosphorus fertilizers as well as the absorption of these heavy metals by velvet green bean grown on soil amended with such fertilizers. The experiment was set up as a completely randomized design in a factorial scheme. The factors were four phosphorus sources (triple superphosphate-TS, Yorin thermophosphate-YT, Araxa rock phosphate-AP, and Gafsa rock phosphate-GP) applied at five rates (0, 92, 183, 275, and 366 kg ha -1 of P 2 O 5 ). The data obtained were submitted to variance and regression analysis. Lead availability to velvet bean was not altered as a result of fertilizer application. On the other hand, Cd uptake was significantly increased with addition of the tested fertilizers. Such an increase was a function of the rate. The highest Cd contents in shoots was reached by YT and TS applications, whereas the lowest one resulted from rock phosphate treatments. All the phosphorus sources tested increased Cd uptake in the first harvest. For the second harvest, Cd content in the shoot was detected only in plants grown on TS and GP amended soils.
from 0.0 to 71.1%, R. solani from 0.0 to 18.0% and S. rolfsii from 0.0 to 13.3%. Frequencies of F... more from 0.0 to 71.1%, R. solani from 0.0 to 18.0% and S. rolfsii from 0.0 to 13.3%. Frequencies of F. solani and M. cannonballus were respectively higher in melons types Orange (57.1%) and Cantaloupe (40.9%), as well as in areas with one or two years (45.4%) and with more than five years of cropping (48.2%). Isolation frequencies for F. solani and M. cannonballus were inversely correlated (r = -0.79), and influenced by the amount of Bacillus spp. in the soil (r = -0.71 and 0.80, respectively). The frequency of M. phaseolina was correlated with phosphorus level (r = 0.68); R. solani with flocculation degree (r = 0.67), field capacity (r = - 0.81), pH (r = -0.75), aluminum level (r = 0.85) and total acidity (r = 0.69), while isolation frequency of S. rolfsii correlated with permanent wilting point (r = -0.78) and available soil water (r = 0.75).
Although silicon (Si) is not an essential element, it presents a close relationship with the alle... more Although silicon (Si) is not an essential element, it presents a close relationship with the alleviation of heavy-metal toxicity to plants. This work was carried out to evaluate the effects of Si application to soil on the amelioration of metal stress to maize grown on a contaminated soil amended with Si (0, 50, 100, 150, and 200 mg kg -1 ) as calcium silicate (CaSiO 3 ). Additionally, the cadmium (Cd) and zink (Zn) bioavailability as well as their distribution into soil fractions was also studied. The results showed that adding Si to a Cd-and Zn-contaminated soil effectively diminished the metal stress and resulted in biomass increase in comparison to metal-contaminated soil not treated with Si. This relied on Cd and Zn immobilization in soil rather than on the increase of soil pH driven by calcium silicate application. Silicon altered the Cd and Zn distribution in soil fractions, decreasing the most bioavailable pools and increasing the allocation of metals into more stable fractions such as organic matter and crystalline iron oxides.
Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy met... more Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy metals that can contaminate the soil and threat the health of animals and humans. The present study focused the determination of Cd and Pb concentrations in different phosphorus fertilizers as well as the absorption of these heavy metals by velvet green bean grown on soil amended with such fertilizers. The experiment was set up as a completely randomized design in a factorial scheme. The factors were four phosphorus sources (triple superphosphate-TS, Yorin thermophosphate-YT, Araxa rock phosphate-AP, and Gafsa rock phosphate-GP) applied at five rates (0, 92, 183, 275, and 366 kg ha-1 of P2O5). The data obtained were submitted to variance and regression analysis. Lead availability to velvet bean was not altered as a result of fertilizer application. On the other hand, Cd uptake was significantly increased with addition of the tested fertilizers. Such an increase was a function of the rate. The highest Cd contents in shoots was reached by YT and TS applications, whereas the lowest one resulted from rock phosphate treatments. All the phosphorus sources tested increased Cd uptake in the first harvest. For the second harvest, Cd content in the shoot was detected only in plants grown on TS and GP amended soils.
ABSTRACT: Nutritionally enhanced beans (NEB) with more Fe and Zn than conventional beans (CB) an... more ABSTRACT: Nutritionally enhanced beans (NEB) with more Fe and Zn than conventional beans (CB) and nutritionally enhanced maize (NEM) with more tryptophan and lysine than conventional maize (CM) were developed as part of a crop-biofortification strategy to improve human nutrition. Proxy measures were used to assess Fe and Zn bioavailability and protein digestibility of a bean recipe (fríjol sancochado) and a maize–milk recipe (mazamorra) prepared with enhanced or conventional crops in Colombia. Fe concentration was similar in the cooked NEB and CB and in NEM and CM (P≥ 0.05); in vitro Fe dialyzability was similar in cooked NEB (9.52%) and CB (9.72%) and greater for NEM (37.01%) than CM (32.24%). Zn concentration was higher in the uncooked and cooked NEB than in the CB (P < 0.05); phytate: Zn molar ratios were high in cooked NEB (36: 1) and CB (47: 1), suggesting low Zn bioavailability, and not different from each other (P = 0.07). There were no differences in Zn concentration or phytate: Zn molar ratio in the maize recipes. Nitrogen, tryptophan, and lysine concentrations were higher in the cooked NEM than CM; nitrogen was higher in the cooked NEB than CB (P < 0.05). In vitro protein digestibility was comparable (82% to 83%) for NEM and CM and higher for NEB (84%) than for CB (82%). The higher nutrient concentrations + similar bioavailability (protein in NEM, Zn in NEB), same nutrient concentrations + higher bioavailability (Fe in NEM) or higher nutrient concentrations + higher bioavailability (protein in NEB) can translate into more nutrients absorbed and utilized by the body.
Rams exhibiting relatively high levels of sexual performance (HP) repeat-breed the same female fe... more Rams exhibiting relatively high levels of sexual performance (HP) repeat-breed the same female fewer times than low-performing (LP) rams. The objective of this study was to determine if HP and LP bulls differed in their tendency to repeat-breed individual females. Eighteen sexually experienced Angus bulls (20±60 months of age) were tested individually with 10 unrestrained, estrous females. The sexual behaviors of all cattle were recorded until the bull achieved six services (ejaculations). Bulls were tested on 2 days with at least 10 days between tests. Frequencies of recorded sexual behaviors were higher for LP than HP bulls (P < 0:05), possibly because of the greater time spent in attaining six services. LP and HP bulls did not differ in the number of females serviced. LP bulls serviced the same number of individual females in both tests (4:0 AE 0:3). However, HP bulls serviced a greater number of individual females (repeat-bred less) during Test 2 than Test 1 (4:7 AE 0:3 and 3:0 AE 0:3; P < 0:05). There was no correlation between time to attain six services and the number of different females serviced (r 0:04), but the number of different females serviced positively correlated with age of the bull (r 0:53, P < 0:05). Repeat-breeding of at least one female was observed in 33 of 36 tests (92%). Repeat-breeding at least one female twice in succession was observed in 24 of 36 tests (67%). There were 12 of 36 tests (33%) in which a female was serviced twice but not in succession. Females were serviced three times in succession in seven tests (19.4%). Sexual performance level did not in¯uence mate preferences or the incidence of repeat-breeding during tests. #
O lodo de esgoto obtido do tratamento das águas servidas contém considerável percentual de matéri... more O lodo de esgoto obtido do tratamento das águas servidas contém considerável percentual de matéria orgânica e de elementos essenciais para as plantas, podendo desempenhar importante papel na produção agrícola e na manutenção da fertilidade do solo. O presente trabalho objetivou estudar o efeito da aplicação de doses crescentes de lodo produzido pela Companhia Pernambucana de Saneamento (COMPESA) sobre as características químicas de dois solos, quantidades de metais pesados absorvidas e crescimento de plantas de milho e de feijoeiro cultivadas em casa de vegetação, visando à futura utilização do lodo em ensaios de campo. Foram utilizados dois tipos de solos com diferentes teores de argila aos quais foram adicionadas seis doses de lodo de esgoto (equivalentes a 0, 10, 20, 30, 40 e 60 Mg ha-1). As aplicações promoveram diminuição do pH e aumento dos teores de matéria orgânica, nitrogênio total, fósforo, potássio, sódio, cálcio e magnésio em ambos os solos, exceção feita aos teores de sódio e potássio de um deles. As doses de lodo de esgoto aumentaram a produção de matéria seca do milho e do feijoeiro. Os teores dos metais Zn, Cu, Mn, Fe e Pb no lodo, no solo e nas plantas estiveram abaixo dos limites estabelecidos para utilização agrícola, o que permite sua aplicação sem maiores riscos ao ambiente.
Although silicon (Si) is not an essential element, it presents a close relationship with the alle... more Although silicon (Si) is not an essential element, it presents a close relationship with the alleviation of heavy-metal toxicity to plants. This work was carried out to evaluate the effects of Si application to soil on the amelioration of metal stress to maize grown on a contaminated soil amended with Si (0, 50, 100, 150, and 200 mg kg–1) as calcium silicate (CaSiO3). Additionally, the cadmium (Cd) and zinc (Zn) bioavailability as well as their distribution into soil fractions was also studied. The results showed that adding Si to a Cd- and Zn-contaminated soil effectively diminished the metal stress and resulted in biomass increase in comparison to metal-contaminated soil not treated with Si. This relied on Cd and Zn immobilization in soil rather than on the increase of soil pH driven by calcium silicate application. Silicon altered the Cd and Zn distribution in soil fractions, decreasing the most bioavailable pools and increasing the allocation of metals into more stable fractions such as organic matter and crystalline iron oxides.
Silicon presents a close relationship with the amelioration of heavy metals phytotoxicity. Howeve... more Silicon presents a close relationship with the amelioration of heavy metals phytotoxicity. However, mechanisms of Si-mediated alleviation of metal stress remains poorly understood. This work aimed at studying the relationship between the accumulation of Si, Cd, and Zn and the tolerance and structural alterations displayed by maize plants grown on a Cd and Zn enriched soil treated with doses of Si (0, 50, 100, 150, and 200mg kg−1) as calcium silicate (CaSiO3). The results showed that the maize plants treated with Si presented not only biomass increasing but also higher metal accumulation. Significant structural alterations on xylem diameter, mesophyll and epidermis thickness, and transversal area occupied by collenchyma and midvein were also observed as a result of Si application. The deposition of silica in the endodermis and pericycle of roots seems to play an important role on the maize tolerance to Cd and Zn stress.
Phytoextraction has emerged as a novel approach to clean up metal-polluted soils in which plants ... more Phytoextraction has emerged as a novel approach to clean up metal-polluted soils in which plants are used to transfer toxic metals from soils to shoots. This review provides a synthesis of current knowledge on phytoextraction of metals from soils and their accumulation in plants. The objective is to integrate soil-related (root exudates and chemical amendments) and biological advances to suggest research needs and future directions. As far as can be deduced from the literature, it will be some time before phytoextraction may be established as a commercial technology. For chemically-assisted phytoextraction, research has not shown easily biodegradable compounds to overcome the risks associated with the use of EDTA for poorly available metals in soils. On the other hand, significant progress has been made on the physiological and molecular aspects regarding tolerance and phytoaccumulation of metals in plants. A multidisciplinary approach is warranted to make phytoextraction a feasible commercial technology to remediate metal-polluted soils.
Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy met... more Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy metals that can contaminate the soil and threat the health of animals and humans. The present study focused the determination of Cd and Pb concentrations in different phosphorus fertilizers as well as the absorption of these heavy metals by velvet green bean grown on soil amended with such fertilizers. The experiment was set up as a completely randomized design in a factorial scheme. The factors were four phosphorus sources (triple superphosphate-TS, Yorin thermophosphate-YT, Araxa rock phosphate-AP, and Gafsa rock phosphate-GP) applied at five rates (0, 92, 183, 275, and 366 kg ha -1 of P 2 O 5 ). The data obtained were submitted to variance and regression analysis. Lead availability to velvet bean was not altered as a result of fertilizer application. On the other hand, Cd uptake was significantly increased with addition of the tested fertilizers. Such an increase was a function of the rate. The highest Cd contents in shoots was reached by YT and TS applications, whereas the lowest one resulted from rock phosphate treatments. All the phosphorus sources tested increased Cd uptake in the first harvest. For the second harvest, Cd content in the shoot was detected only in plants grown on TS and GP amended soils.
from 0.0 to 71.1%, R. solani from 0.0 to 18.0% and S. rolfsii from 0.0 to 13.3%. Frequencies of F... more from 0.0 to 71.1%, R. solani from 0.0 to 18.0% and S. rolfsii from 0.0 to 13.3%. Frequencies of F. solani and M. cannonballus were respectively higher in melons types Orange (57.1%) and Cantaloupe (40.9%), as well as in areas with one or two years (45.4%) and with more than five years of cropping (48.2%). Isolation frequencies for F. solani and M. cannonballus were inversely correlated (r = -0.79), and influenced by the amount of Bacillus spp. in the soil (r = -0.71 and 0.80, respectively). The frequency of M. phaseolina was correlated with phosphorus level (r = 0.68); R. solani with flocculation degree (r = 0.67), field capacity (r = - 0.81), pH (r = -0.75), aluminum level (r = 0.85) and total acidity (r = 0.69), while isolation frequency of S. rolfsii correlated with permanent wilting point (r = -0.78) and available soil water (r = 0.75).
Although silicon (Si) is not an essential element, it presents a close relationship with the alle... more Although silicon (Si) is not an essential element, it presents a close relationship with the alleviation of heavy-metal toxicity to plants. This work was carried out to evaluate the effects of Si application to soil on the amelioration of metal stress to maize grown on a contaminated soil amended with Si (0, 50, 100, 150, and 200 mg kg -1 ) as calcium silicate (CaSiO 3 ). Additionally, the cadmium (Cd) and zink (Zn) bioavailability as well as their distribution into soil fractions was also studied. The results showed that adding Si to a Cd-and Zn-contaminated soil effectively diminished the metal stress and resulted in biomass increase in comparison to metal-contaminated soil not treated with Si. This relied on Cd and Zn immobilization in soil rather than on the increase of soil pH driven by calcium silicate application. Silicon altered the Cd and Zn distribution in soil fractions, decreasing the most bioavailable pools and increasing the allocation of metals into more stable fractions such as organic matter and crystalline iron oxides.
Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy met... more Phosphorus fertilizers are essential to obtain high productivity, however, they contain heavy metals that can contaminate the soil and threat the health of animals and humans. The present study focused the determination of Cd and Pb concentrations in different phosphorus fertilizers as well as the absorption of these heavy metals by velvet green bean grown on soil amended with such fertilizers. The experiment was set up as a completely randomized design in a factorial scheme. The factors were four phosphorus sources (triple superphosphate-TS, Yorin thermophosphate-YT, Araxa rock phosphate-AP, and Gafsa rock phosphate-GP) applied at five rates (0, 92, 183, 275, and 366 kg ha-1 of P2O5). The data obtained were submitted to variance and regression analysis. Lead availability to velvet bean was not altered as a result of fertilizer application. On the other hand, Cd uptake was significantly increased with addition of the tested fertilizers. Such an increase was a function of the rate. The highest Cd contents in shoots was reached by YT and TS applications, whereas the lowest one resulted from rock phosphate treatments. All the phosphorus sources tested increased Cd uptake in the first harvest. For the second harvest, Cd content in the shoot was detected only in plants grown on TS and GP amended soils.
ABSTRACT: Nutritionally enhanced beans (NEB) with more Fe and Zn than conventional beans (CB) an... more ABSTRACT: Nutritionally enhanced beans (NEB) with more Fe and Zn than conventional beans (CB) and nutritionally enhanced maize (NEM) with more tryptophan and lysine than conventional maize (CM) were developed as part of a crop-biofortification strategy to improve human nutrition. Proxy measures were used to assess Fe and Zn bioavailability and protein digestibility of a bean recipe (fríjol sancochado) and a maize–milk recipe (mazamorra) prepared with enhanced or conventional crops in Colombia. Fe concentration was similar in the cooked NEB and CB and in NEM and CM (P≥ 0.05); in vitro Fe dialyzability was similar in cooked NEB (9.52%) and CB (9.72%) and greater for NEM (37.01%) than CM (32.24%). Zn concentration was higher in the uncooked and cooked NEB than in the CB (P < 0.05); phytate: Zn molar ratios were high in cooked NEB (36: 1) and CB (47: 1), suggesting low Zn bioavailability, and not different from each other (P = 0.07). There were no differences in Zn concentration or phytate: Zn molar ratio in the maize recipes. Nitrogen, tryptophan, and lysine concentrations were higher in the cooked NEM than CM; nitrogen was higher in the cooked NEB than CB (P < 0.05). In vitro protein digestibility was comparable (82% to 83%) for NEM and CM and higher for NEB (84%) than for CB (82%). The higher nutrient concentrations + similar bioavailability (protein in NEM, Zn in NEB), same nutrient concentrations + higher bioavailability (Fe in NEM) or higher nutrient concentrations + higher bioavailability (protein in NEB) can translate into more nutrients absorbed and utilized by the body.
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Papers by William Araujo