Acute toxicity of three herbicide formulations of Astyanax altiparanae (Characiformes, Characidae), an emerging neotropical fish model species.

Herbicides are used in agriculture to control harmful crop weeds, prevent algae proliferation, and enhance macrophyte growth. Herbicide contamination of water bodies might exert toxic effects on fish in different development stages. Sperm, embryos, and adults of Astyanax altiparanae were used as a model to examine the detrimental effects of the following herbicide formulations: Roundup Transorb® (glyphosate), Arsenal® NA (imazapyr), and Reglone® (diquat). The lethal concentration 50 (LC50) values for adults using glyphosate and imazapyr were 3.14 mg/L and 4.59 mg/L, respectively, while the LC50 was higher than 28 mg/L for diquat. For the initial stages of embryo development, LC50 values were 16.52 mg/L glyphosate, 9.33 mg/L imazapyr, and 1084 mg/L diquat. Inhibition of sperm motility was noted at 252 mg/L glyphosate, 137 mg/L imazapyr, and 11,300 mg/L diquat, with an average sperm viability of 12.5%, 73.2%, and 89.3%, respectively, compared to 87.5% detected to control. A. altiparanae exhibited different sensitivities to the herbicide formulations investigated in the developmental stages evaluated. Roundup Transorb® exposure was more toxic for adults, while Arsenal® NA was most harmful for early embryonic development and inhibited sperm motility. Reglone® demonstrated low toxicity for A. altiparanae compared to Roundup Transorb® and Arsenal® NA. A. altiparanae may be considered an emerging fish model for toxicological studies for the neotropical region due to its wide distribution and biological characteristics.

Herbicide tolerance and gene silencing stability over generations in the ricin bio-detoxicated castor bean.

Castor bean (Ricinus communis L.) is an important cultivated oilseed. Seeds contain ricinoleic acid, a valuable product for a variety of industries. Castor cake is a residue of ricinoleic manufacture and could be used as animal feed due to its high amount of protein. However, castor cake contains ricin and RCA120, both highly toxic and allergenic proteins. In 2017, we reported the development of a transgenic event (named TB14S-5D) with an undetectable amount of ricin/RCA120. In the present work, we evaluate TB14S-5D for tolerance to the herbicide imazapyr, as it contains the selectable marker gene, ahas, which was previously isolated from Arabidopsis thaliana and contains a mutation at position 653 bp. In addition, we demonstrated that the ricin coding genes are stably silenced over three generations.

Phytostimulation of lowland soil contaminated with imidazolinone herbicides.

The phytostimulation is a phytoremediation technique that can be used to remediate area contaminated with herbicides. It is necessary to select plants with high capacity to stimulate soil microbial activity. The present work aimed at evaluating seven plant species regarding their ability to phytostimulate soil and enhance the degradation of the herbicides imazethapyr, imazapic and imazapyr in a lowland soil. An Alfisol Albaqualf was cultivated with the following species, Canavalia ensiformis, Glycine max, Oryza sativa cultivar PUITÁ INTA CL, Lolium multiflorum, Vicia sativa and consortium Lotus corniculatus + Trifolium repens. The rhizosphere of these plants and non-rhizospheric (uncultivated soil) as a control were contaminated in laboratory with analytical standart of the three herbicides, at rates of 0, 150, 300 and 750 g a.i. ha-1, in separate assays. Biodegradation was estimated by quantifying C-CO2 production and through analysis of herbicides residues in soil using liquid chromatography. Results show that biodegradation of herbicides imazethapyr, imazapic and imazapyr was higher in vegetated soil than in unvegetated soil. The leguminous species Canavalia ensiformis, Glycine max, Vicia sativa and consortium of Lotus corniculatus + Trifolium repens showed a great capacity to promote soil microbial, resulting in average biodegradation rates of 91, 92 and 93% for herbicides imazethapyr, imazapic and imazapyr in soil, respectively.

Selectivity of herbicides in native forest species of cerrado / Seletividade de herbicidas em espécies florestais nativas do cerrado

A aggravating problems in forest management is weed interference, which is a factor that modifies adaptation and reduces plant growth. The use of herbicides is an indispensable practice to mitigate these effects in reforestation areas. This study aimed to evaluate the selectivity of glyphosate and imazapyr in native plants of the Brazilian Cerrado, such as: Schinus terebinthifolia (Anacardiaceae), Peltophorum dubium (Fabaceae) and Handroanthus albus (Bignoniaceae). The trial was carried out in a greenhouse at Unit of Aquidauana/UEMS. Experimental design was completely randomized, with seven treatments and five replications. Selectivity of the herbicides in the seedlings of these species was evaluated at 7, 14, 21, 28 and 60 days after application (DAA) of the herbicides, by means of a percentage scale of notes, where 0% corresponds to no injury and 100% corresponds to plant death. At the same time, for the weed control evaluation, visual analysis was also performed at 7, 14, 21, 28 and 60 DAA of the herbicides, where 100% was considered plant death and 0% no injury to weed. Imazapyr herbicide, when applied in the initial post-emergence in its lower level, it is selective to the tree species, but in the other concentrations it can affect differently the survival of them. Glyphosate herbicide was the least selective to the tree species in its different concentrations, causing phytotoxic effects with changes in the seedlings morphology. The results of this study could help in the integrated management of weeds and contribute to the efficient herbicide use in planting forest species in the Cerrado.

Um dos problemas mais agravantes no manejo florestal é a interferência que as plantas daninhas podem causar no desenvolvimento e crescimento das plantas. O uso de herbicidas é uma prática indispensável para atenuar esses efeitos em áreas de reflorestamento. Este trabalho teve como objetivo avaliar a seletividade dos herbicidas glyphosate e imazapyr em mudas de espécies nativas do Cerrado brasileiro, tais como: Schinus terebinthifolia (Anacardiaceae), Peltophorum dubium (Fabaceae) e Handroanthus albus (Bignoniaceae). O experimento foi conduzido em Casa de Vegetação, na Unidade Universitária de Aquidauana/UEMS. O delineamento experimental utilizado foi o inteiramente casualizado, com sete tratamentos e cinco repetições. A seletividade dos herbicidas nas mudas destas espécies foi avaliada aos 7, 14, 21, 28 e 60 dias após aplicação (DAA) dos herbicidas, por meio de uma escala percentual de notas, em que 0% corresponde a nenhuma injúria e 100% corresponde a morte da planta. Paralelamente, para a avaliação do controle das plantas daninhas também foi realizada analise visual aos 7, 14, 21, 28 e 60 dias após aplicação (DAA) dos herbicidas, através da avaliação visual de controle, onde 100% consideram-se morte da daninha e 0% nenhuma injúria à planta daninha. O herbicida imazapyr aplicado em pós-emergência inicial em sua menor dosagem é seletivo as espécies arbóreas, mas em maiores concentrações pode afetar sua sobrevivência de forma diferenciada nas espécies. O herbicida glyphosate foi o menos seletivo às espécies arbóreas em suas diferentes concentrações, causando intoxicações às mudas com alterações em sua morfologia. Os resultados deste trabalho podem auxiliar no manejo integrado de plantas daninhas e contribuir para o uso eficiente de herbicidas em plantios de espécies florestais no cerrado.

Leaching and residual activity of imidazolinone herbicides in lowland soils / Lixiviação dos herbicidas imidazolinonas em solo de várzea

Herbicides used in the Clearfield® rice (Oryza sativa L.) production system have a potential for leaching. This can result in contamination of underground water resources and cause injury to not tolerant crops that are sown in a succession and/or crop rotation. The objective of this study was to determine the leaching potential and the residual activity of the herbicides used in the Clearfield® rice system. The experiment was conducted over a period of two years and consisted of conducting a field test to be followed by two bioassays with a year of difference between their implementation. Initially an experiment was conducted in lowland area where it was planted the cultivar of rice ‘PUITA INTA CL. Approximately one and two years thereafter, soil samples from each plot were collected at intervals of 5cm to a depth of 30cm (B factor) for the bioassay to evaluate persistence of herbicides. Factor A was composed of mixtures formulated of imazethapyr + imazapic (75 + 25g a.i. L-1), imazapyr + imazapic (525 + 175g a.i. kg-1) in two doses, imazethapyr (100g a.i. L-1) and treatment control without application. Basing on results, it was concluded that the mixtures imazethapyr + imazapic, imazapyr + imazapic and imazethapyr leached into the soil, reaching depths of up to 25cm in lowland soil. Imidazolinone herbicides used today in the irrigated rice Clearfield® system are persistent in soil, and their phytotoxic activity can be observed up to two years after application.(AU)

Os herbicidas utilizados no sistema Clearfield® de produção de arroz irrigado (Oryza sativa L.) apresentam potencial de lixiviação. Isso pode causar contaminação de mananciais hídricos subterrâneos e fitotoxicidade as culturas não tolerantes semeadas em sucessão e/ou rotação. O objetivo deste trabalho foi determinar o potencial de lixiviação e o efeito residual dos herbicidas utilizados no sistema Clearfield® de arroz irrigado. O experimento foi conduzido durante dois anos e consistiu da realização de dois bioensaio com diferença de um ano entre a implantação dos mesmos. Inicialmente foi instalado o experimento em área de várzea onde foi semeada a cultivar de arroz ‘Puitá INTA CL em área de várzea. Aproximadamente um e dois anos após, foram coletadas amostras de solo de cada parcela, em intervalos de 5cm até a profundidade de 30cm (fator B) para a realização do bioensaio a fim de avaliar persistência dos herbicidas. O fator A foi constituído pelas misturas formuladas imazethapyr + imazapic (75 + 25g i.a. L-1), imazapyr + imazapic (525 + 175g i.a. kg-1) em duas doses, imazethapyr (100g i.a. L-1) e um tratamento testemunha sem aplicação. Com os resultados obtidos, foi possível concluir que as misturas imazethapyr + imazapic, imazapyr + imazapic e imazethapyr lixiviam no solo, atingindo profundidades de até 25cm em solo de várzea. Os herbicidas imidazolinonas, hoje utilizados no sistema Clearfiel® de arroz irrigado, são persistentes no solo podendo seus efeitos fitotóxicos serem observados até dois anos após sua aplicação.(AU)

Leaching and residual activity of imidazolinone herbicides in lowland soils / Lixiviação dos herbicidas imidazolinonas em solo de várzea

Herbicides used in the Clearfield® rice (Oryza sativa L.) production system have a potential for leaching. This can result in contamination of underground water resources and cause injury to not tolerant crops that are sown in a succession and/or crop rotation. The objective of this study was to determine the leaching potential and the residual activity of the herbicides used in the Clearfield® rice system. The experiment was conducted over a period of two years and consisted of conducting a field test to be followed by two bioassays with a year of difference between their implementation. Initially an experiment was conducted in lowland area where it was planted the cultivar of rice ‘PUITA INTA CL’. Approximately one and two years thereafter, soil samples from each plot were collected at intervals of 5cm to a depth of 30cm (B factor) for the bioassay to evaluate persistence of herbicides. Factor A was composed of mixtures formulated of imazethapyr + imazapic (75 + 25g a.i. L-1), imazapyr + imazapic (525 + 175g a.i. kg-1) in two doses, imazethapyr (100g a.i. L-1) and treatment control without application. Basing on results, it was concluded that the mixtures imazethapyr + imazapic, imazapyr + imazapic and imazethapyr leached into the soil, reaching depths of up to 25cm in lowland soil. Imidazolinone herbicides used today in the irrigated rice Clearfield® system are persistent in soil, and their phytotoxic activity can be observed up to two years after application.

Os herbicidas utilizados no sistema Clearfield® de produção de arroz irrigado (Oryza sativa L.) apresentam potencial de lixiviação. Isso pode causar contaminação de mananciais hídricos subterrâneos e fitotoxicidade as culturas não tolerantes semeadas em sucessão e/ou rotação. O objetivo deste trabalho foi determinar o potencial de lixiviação e o efeito residual dos herbicidas utilizados no sistema Clearfield® de arroz irrigado. O experimento foi conduzido durante dois anos e consistiu da realização de dois bioensaio com diferença de um ano entre a implantação dos mesmos. Inicialmente foi instalado o experimento em área de várzea onde foi semeada a cultivar de arroz ‘Puitá INTA CL’ em área de várzea. Aproximadamente um e dois anos após, foram coletadas amostras de solo de cada parcela, em intervalos de 5cm até a profundidade de 30cm (fator B) para a realização do bioensaio a fim de avaliar persistência dos herbicidas. O fator A foi constituído pelas misturas formuladas imazethapyr + imazapic (75 + 25g i.a. L-1), imazapyr + imazapic (525 + 175g i.a. kg-1) em duas doses, imazethapyr (100g i.a. L-1) e um tratamento testemunha sem aplicação. Com os resultados obtidos, foi possível concluir que as misturas imazethapyr + imazapic, imazapyr + imazapic e imazethapyr lixiviam no solo, atingindo profundidades de até 25cm em solo de várzea. Os herbicidas imidazolinonas, hoje utilizados no sistema Clearfiel® de arroz irrigado, são persistentes no solo podendo seus efeitos fitotóxicos serem observados até dois anos após sua aplicação.

Leaching and residual activity of imidazolinone herbicides in lowland soils

ABSTRACT: Herbicides used in the Clearfield® rice (Oryza sativa L.) production system have a potential for leaching. This can result in contamination of underground water resources and cause injury to not tolerant crops that are sown in a succession and/or crop rotation. The objective of this study was to determine the leaching potential and the residual activity of the herbicides used in the Clearfield® rice system. The experiment was conducted over a period of two years and consisted of conducting a field test to be followed by two bioassays with a year of difference between their implementation. Initially an experiment was conducted in lowland area where it was planted the cultivar of rice PUITA INTA CL. Approximately one and two years thereafter, soil samples from each plot were collected at intervals of 5cm to a depth of 30cm (B factor) for the bioassay to evaluate persistence of herbicides. Factor A was composed of mixtures formulated of imazethapyr + imazapic (75 + 25g a.i. L-1), imazapyr + imazapic (525 + 175g a.i. kg-1) in two doses, imazethapyr (100g a.i. L-1) and treatment control without application. Basing on results, it was concluded that the mixtures imazethapyr + imazapic, imazapyr + imazapic and imazethapyr leached into the soil, reaching depths of up to 25cm in lowland soil. Imidazolinone herbicides used today in the irrigated rice Clearfield® system are persistent in soil, and their phytotoxic activity can be observed up to two years after application.

RESUMO: Os herbicidas utilizados no sistema Clearfield® de produção de arroz irrigado (Oryza sativa L.) apresentam potencial de lixiviação. Isso pode causar contaminação de mananciais hídricos subterrâneos e fitotoxicidade as culturas não tolerantes semeadas em sucessão e/ou rotação. O objetivo deste trabalho foi determinar o potencial de lixiviação e o efeito residual dos herbicidas utilizados no sistema Clearfield® de arroz irrigado. O experimento foi conduzido durante dois anos e consistiu da realização de dois bioensaio com diferença de um ano entre a implantação dos mesmos. Inicialmente foi instalado o experimento em área de várzea onde foi semeada a cultivar de arroz Puitá INTA CL em área de várzea. Aproximadamente um e dois anos após, foram coletadas amostras de solo de cada parcela, em intervalos de 5cm até a profundidade de 30cm (fator B) para a realização do bioensaio a fim de avaliar persistência dos herbicidas. O fator A foi constituído pelas misturas formuladas imazethapyr + imazapic (75 + 25g i.a. L-1), imazapyr + imazapic (525 + 175g i.a. kg-1) em duas doses, imazethapyr (100g i.a. L-1) e um tratamento testemunha sem aplicação. Com os resultados obtidos, foi possível concluir que as misturas imazethapyr + imazapic, imazapyr + imazapic e imazethapyr lixiviam no solo, atingindo profundidades de até 25cm em solo de várzea. Os herbicidas imidazolinonas, hoje utilizados no sistema Clearfiel® de arroz irrigado, são persistentes no solo podendo seus efeitos fitotóxicos serem observados até dois anos após sua aplicação.

Leaching and residual activity of imidazolinone herbicides in lowland soils / Lixiviação dos herbicidas imidazolinonas em solo de várzea

ABSTRACT: Herbicides used in the Clearfield® rice (Oryza sativa L.) production system have a potential for leaching. This can result in contamination of underground water resources and cause injury to not tolerant crops that are sown in a succession and/or crop rotation. The objective of this study was to determine the leaching potential and the residual activity of the herbicides used in the Clearfield® rice system. The experiment was conducted over a period of two years and consisted of conducting a field test to be followed by two bioassays with a year of difference between their implementation. Initially an experiment was conducted in lowland area where it was planted the cultivar of rice ‘PUITA INTA CL’. Approximately one and two years thereafter, soil samples from each plot were collected at intervals of 5cm to a depth of 30cm (B factor) for the bioassay to evaluate persistence of herbicides. Factor A was composed of mixtures formulated of imazethapyr + imazapic (75 + 25g a.i. L-1), imazapyr + imazapic (525 + 175g a.i. kg-1) in two doses, imazethapyr (100g a.i. L-1) and treatment control without application. Basing on results, it was concluded that the mixtures imazethapyr + imazapic, imazapyr + imazapic and imazethapyr leached into the soil, reaching depths of up to 25cm in lowland soil. Imidazolinone herbicides used today in the irrigated rice Clearfield® system are persistent in soil, and their phytotoxic activity can be observed up to two years after application.

RESUMO: Os herbicidas utilizados no sistema Clearfield® de produção de arroz irrigado (Oryza sativa L.) apresentam potencial de lixiviação. Isso pode causar contaminação de mananciais hídricos subterrâneos e fitotoxicidade as culturas não tolerantes semeadas em sucessão e/ou rotação. O objetivo deste trabalho foi determinar o potencial de lixiviação e o efeito residual dos herbicidas utilizados no sistema Clearfield® de arroz irrigado. O experimento foi conduzido durante dois anos e consistiu da realização de dois bioensaio com diferença de um ano entre a implantação dos mesmos. Inicialmente foi instalado o experimento em área de várzea onde foi semeada a cultivar de arroz ‘Puitá INTA CL’ em área de várzea. Aproximadamente um e dois anos após, foram coletadas amostras de solo de cada parcela, em intervalos de 5cm até a profundidade de 30cm (fator B) para a realização do bioensaio a fim de avaliar persistência dos herbicidas. O fator A foi constituído pelas misturas formuladas imazethapyr + imazapic (75 + 25g i.a. L-1), imazapyr + imazapic (525 + 175g i.a. kg-1) em duas doses, imazethapyr (100g i.a. L-1) e um tratamento testemunha sem aplicação. Com os resultados obtidos, foi possível concluir que as misturas imazethapyr + imazapic, imazapyr + imazapic e imazethapyr lixiviam no solo, atingindo profundidades de até 25cm em solo de várzea. Os herbicidas imidazolinonas, hoje utilizados no sistema Clearfiel® de arroz irrigado, são persistentes no solo podendo seus efeitos fitotóxicos serem observados até dois anos após sua aplicação.

Persistence and sorption of imazapyr in three Argentinean soils.

Imazapyr is a herbicide widely used for weed control in imidazolinone-tolerant sunflower. Imazapyr has a high potential for leaching into groundwater because it is highly water-soluble, persistent in soil, and only weakly sorbed by soils. There is a lack of information available in Argentina concerning groundwater leaching of imazapyr. Therefore, the objective of the present study was to determine the persistence and sorption of imazapyr in 3 Argentinean soils (Tandil, Anguil, and Cerro Azul sites). The presence and concentration of imazapyr were determined and quantified by ultra-performance liquid chromatography and tandem mass spectrometry. The persistence in soils followed the order: Cerro Azul > Tandil > Anguil, with half-life values of 121 d, 75 d, and 37 d, respectively. The half-life of imazapyr was negatively associated with soil pH and iron and aluminum content, and was positively related to clay content. Imazapyr sorption was found to be well described by the Freundlich isotherm. Soil pH and clay, iron, and aluminum contents were the main factors affecting the sorption of imazapyr. The sorption had a limiting effect on the degradation rate. Under certain conditions, the weak sorption and high persistence may increase the movement of imazapyr in the soil profile and the risk of groundwater pollution.

Ação de herbicidas sistémicos não-seletivos sobre a progénie de soja quando aplicados durante a fase reprodutiva das plantas-mãe

The purpose of ïhis research was to evaluate germination of soybean seeds and initial development of seediings, whose mother plants were treated with sub-rates of svstemic nonselective herbicides during late stages of development. Field, laboratory, and greenhouse experiments were carried ouï aï Agronomy School of UFRGS, in Porto Alegre, RS, during the period 1995/97. Treatments consisted offield appiications of the herbicides 2,4-D at rates of 5 and l0g/ha a. e., imazapvr at 25 and 50g/ha a.e., and sulfosate at 25 and 50g/ha a.e. The se herbicides were sprayed eiïher at beginning of flowering (R1 stage) or at beginning ofpod development (R3 stage) of soybean plants. It was proved that appiication of imazapyr on sovbean plants at beginning of pod development decreased germination of seeds formed on those plants. The appiication of 2,4-D and sulfosate did not ajfect soybean seed germination, at tested rates, independentiy if appiied eiïher at beginning of flowering or pod development of the mother plants. Seediing ïzeight, dry matter of shoots, of roots and total dry matter of seediings of the progeny were not affected by herbicides appiied at Ri and Rs stages of sovbean plants. However, sprayings of herbicides 2,4-D (at 5 and l0g/ha a.e.), imazapyr (at 25 and 50g/ha a.e.), and sulfosate (at 25 and 50g/ha a.e.), appiied at beginning of pod development of mother plants, in general reduced hvpocotyl and root lengtli of sovbean seed-lings of tire progeny.

Com o objetivo de avaliar a germinação de sementes de soja e o desenvolvimento inicial de plântulas, cujas plantas-mãe foram tratadas com subdoses de herbicidas sistêmicos nâo-seletivos em estádios avançados de desenvolvimento, realizaram-se experimentos a campo, em laboratório e em casa-de-vegetação na Faculdade de Agronomia da UFRGS, em Porto Alegre, RS, durante o período 1995/97. Os tratamentos constaram das aplicações a campo dos herbicidas 2,4-D nas doses de 5 e l0g/ha e.a., imawpyr a 25 e 50g/ha e.a. e sulfosate a 25 e 50g/ha e.a., usados no início do florescimento (estádio R1) ou no início da formação de legumes (estádio R3) das plantas de soja. Comprovou-se que a aplicação de imawpyr sobre plantas de soja no início da formação de legumes reduz, a germinação das sementes nelas formadas. A aplicação de 2,4-D e de sulfosate não afeiam a germinação das sementes de soja, nas doses testadas, independente se aplicados no início do florescimento ou da formação de legumes das plantas-mãe. Os parâmetros altura de plântula, massa seca da parte aérea, da parte radicular e total das plântulas da progênie não são afetados pêlos herbicidas aplicados nos estádios Ri e Rj das plantas-mãe de soja. No entanto, as aplicações dos herbicidas 2,4-D (a 5 e l0g/ha e.a.), imazapyr (a 25 e 50g/ha e.a.) e sulfosate (a 25 e 50g/ha e.a.), efetuadas no início da formação dos legumes das plantas-mãe, reduzem os comprimentos do hipocótilo e da raiz, das plântulas da progênie.

Ação de herbicidas sistémicos não-seletivos sobre a progénie de soja quando aplicados durante a fase reprodutiva das plantas-mãe

The purpose of ïhis research was to evaluate germination of soybean seeds and initial development of seediings, whose mother plants were treated with sub-rates of svstemic nonselective herbicides during late stages of development. Field, laboratory, and greenhouse experiments were carried ouï aï Agronomy School of UFRGS, in Porto Alegre, RS, during the period 1995/97. Treatments consisted offield appiications of the herbicides 2,4-D at rates of 5 and l0g/ha a. e., imazapvr at 25 and 50g/ha a.e., and sulfosate at 25 and 50g/ha a.e. The se herbicides were sprayed eiïher at beginning of flowering (R1 stage) or at beginning ofpod development (R3 stage) of soybean plants. It was proved that appiication of imazapyr on sovbean plants at beginning of pod development decreased germination of seeds formed on those plants. The appiication of 2,4-D and sulfosate did not ajfect soybean seed germination, at tested rates, independentiy if appiied eiïher at beginning of flowering or pod development of the mother plants. Seediing ïzeight, dry matter of shoots, of roots and total dry matter of seediings of the progeny were not affected by herbicides appiied at Ri and Rs stages of sovbean plants. However, sprayings of herbicides 2,4-D (at 5 and l0g/ha a.e.), imazapyr (at 25 and 50g/ha a.e.), and sulfosate (at 25 and 50g/ha a.e.), appiied at beginning of pod development of mother plants, in general reduced hvpocotyl and root lengtli of sovbean seed-lings of tire progeny.

Com o objetivo de avaliar a germinação de sementes de soja e o desenvolvimento inicial de plântulas, cujas plantas-mãe foram tratadas com subdoses de herbicidas sistêmicos nâo-seletivos em estádios avançados de desenvolvimento, realizaram-se experimentos a campo, em laboratório e em casa-de-vegetação na Faculdade de Agronomia da UFRGS, em Porto Alegre, RS, durante o período 1995/97. Os tratamentos constaram das aplicações a campo dos herbicidas 2,4-D nas doses de 5 e l0g/ha e.a., imawpyr a 25 e 50g/ha e.a. e sulfosate a 25 e 50g/ha e.a., usados no início do florescimento (estádio R1) ou no início da formação de legumes (estádio R3) das plantas de soja. Comprovou-se que a aplicação de imawpyr sobre plantas de soja no início da formação de legumes reduz, a germinação das sementes nelas formadas. A aplicação de 2,4-D e de sulfosate não afeiam a germinação das sementes de soja, nas doses testadas, independente se aplicados no início do florescimento ou da formação de legumes das plantas-mãe. Os parâmetros altura de plântula, massa seca da parte aérea, da parte radicular e total das plântulas da progênie não são afetados pêlos herbicidas aplicados nos estádios Ri e Rj das plantas-mãe de soja. No entanto, as aplicações dos herbicidas 2,4-D (a 5 e l0g/ha e.a.), imazapyr (a 25 e 50g/ha e.a.) e sulfosate (a 25 e 50g/ha e.a.), efetuadas no início da formação dos legumes das plantas-mãe, reduzem os comprimentos do hipocótilo e da raiz, das plântulas da progênie.