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• 1. [Article] Characterization of cytokinin metabolic enzymes from Phaseolus

  An enzyme catalyzing the formation of O-glucosylzeatin in immature embryos of P. lunatus was purified 2500 fold using ammonium sulfate precipitation followed by affinity and anion exchange chromatography. The ...

  Citation × Citation Citation Abstract Copy Title: Characterization of cytokinin metabolic enzymes from Phaseolus Author: Dixon, Susan C. An enzyme catalyzing the formation of O-glucosylzeatin in immature embryos of P. lunatus was purified 2500 fold using ammonium sulfate precipitation followed by affinity and anion exchange chromatography. The enzyme uses trans-zeatin as substrate (Km 28 uM) but not cis-zeatin. ribosylzeatin, or dihydrozeatin. Both UDP-glucose and UDP-xylose can serve as glycosyl donors, with Kms of 0.2 and 2.7 mM respectively, for the formation of O-glucosylzeatin and O-xylosylzeatin. In comparison, the UDPxylose:zeatin O-xylosyltransferase (Turner et al., 1987) isolated by the same procedures from P. vulgaris embryos uses only UDP-xylose as donor substrate and the Kms for both zeatin and UDP-xylose are much lower (2 and 3 micromolar, respectively). The chromatographic behavior on affinity columns and the molecular weights (approximate Mr 44,000 daltons) of the two enzymes are similar. Results from substrate competition experiments and enzyme separation by anion exchange HPLC indicate a single, distinct, zeatin O-glycosylation enzyme occurs in embryos of each of these Phaseolus species. Title: Characterization of cytokinin metabolic enzymes from Phaseolus Author: Dixon, Susan C. An enzyme catalyzing the formation of O-glucosylzeatin in immature embryos of P. lunatus was purified 2500 fold using ammonium sulfate precipitation followed by affinity and anion exchange chromatography. The enzyme uses trans-zeatin as substrate (Km 28 uM) but not cis-zeatin. ribosylzeatin, or dihydrozeatin. Both UDP-glucose and UDP-xylose can serve as glycosyl donors, with Kms of 0.2 and 2.7 mM respectively, for the formation of O-glucosylzeatin and O-xylosylzeatin. In comparison, the UDPxylose:zeatin O-xylosyltransferase (Turner et al., 1987) isolated by the same procedures from P. vulgaris embryos uses only UDP-xylose as donor substrate and the Kms for both zeatin and UDP-xylose are much lower (2 and 3 micromolar, respectively). The chromatographic behavior on affinity columns and the molecular weights (approximate Mr 44,000 daltons) of the two enzymes are similar. Results from substrate competition experiments and enzyme separation by anion exchange HPLC indicate a single, distinct, zeatin O-glycosylation enzyme occurs in embryos of each of these Phaseolus species. Close

• 2. [Article] The response of beans to fluorodifen as affected by light and other factors

  Studies with fluorodifen were conducted to gain more information about its field performance and the influence of light quantity, quality and timing of exposure on its phytotoxic properties. Uptake and ...

  Citation × Citation Citation Abstract Copy Title: The response of beans to fluorodifen as affected by light and other factors Author: Pollak, Tomas Studies with fluorodifen were conducted to gain more information about its field performance and the influence of light quantity, quality and timing of exposure on its phytotoxic properties. Uptake and trans location in three plant species were also investigated. These studies were aimed at evaluating the usefulness of this chemical as a selective herbicide for controlling weeds in beans (Phaseolus vulgaris L.) in Oregon. Field data compiled for a period of three consecutive years indicated that the highest yields of green beans were obtained when fluorodifen was applied at a rate of 6 lb/A preemergence. At higher rates, crop injury was noticeable in the form of shortening of midrib and necrotic lesions on hypocotyls and other plant tissues such as cotyledons that came into contact with the herbicide. Occasionally these symptoms were observed at rates as low as 1 lb/A under an unspecified set of conditions occurring in the field. A combination of fluorodifen applied preemergence and cultivation two weeks after emergence of the crop provided the best weed controls Shading the crop at different stages of development did not provide an explanation for the cause of stem lesion development, but when shade was provided from application until the first true leaf, phytotoxicity was noticeable. Three soil types and two watering regimes did not provide significant, consistent phytotoxicity or stem burning. By the use of neutral density filters, different intensities of light with the same spectral emission were obtained in growth chambers. Bean and soybean plants were more sensitive to fluorodifen at low levels of light. The percentage dry weight reduction decreased as the light intensity increased from 1,000 to 2,000 ft/c. In determining the critical period in which light enhances fluorodifen injury to beans and soybeans, it was found that plants exposed to light on the second to third day after planting were most severely injured. When filters were used to evaluate the influence of light quality on fluorodifen toxicity to beans and soybeans, these plants were more sensitive to fluorodifen when exposed to yellow and red light than when exposed to blue or white light. Phytotoxic symptoms were observed especially under yellow light. Exposure to light at the time of crop emergence resulted in the greatest phytotoxicity. Autoradiography and radioassay results indicated that ¹⁴C-fluorodifen was absorbed mostly within six hours after application. The distribution pattern remained fairly constant in beans and soybeans with the largest percentage of activity remaining in the treated portion at all times. Greater mobility of the label was observed in cucumber plants with some acropetal and basipetal movement recorded from the treated leaves 12 hours after applications. Covering the treated leaf did not alter the uptake of fluorodifen in any of the three plant species. Following applications to stem and roots, a similar pattern was observed, rapid uptake but little or no mobility. The unicellular algae Chlorella was used to assess the effect of fluorodifen on photosynthesis and respiration of green plant tissues. It was found that the growth of Chlorella was severely affected by low concentrations of fluorodifen in the light. The same herbicide concentrations had no effect in the dark. Under the conditions of this study, fluorodifen caused just a slight increase in the respiration of Chlorella, while photosynthesis was severely inhibited at concentrations of 1 ppm of fluorodifen. In a separate study, the persistence of fluorodifen in soil subjected to different environmental conditions was evaluated by gas chromatography. Fluorodifen was degraded more readily under high temperatures, provided that the soil was dry. Title: The response of beans to fluorodifen as affected by light and other factors Author: Pollak, Tomas Studies with fluorodifen were conducted to gain more information about its field performance and the influence of light quantity, quality and timing of exposure on its phytotoxic properties. Uptake and trans location in three plant species were also investigated. These studies were aimed at evaluating the usefulness of this chemical as a selective herbicide for controlling weeds in beans (Phaseolus vulgaris L.) in Oregon. Field data compiled for a period of three consecutive years indicated that the highest yields of green beans were obtained when fluorodifen was applied at a rate of 6 lb/A preemergence. At higher rates, crop injury was noticeable in the form of shortening of midrib and necrotic lesions on hypocotyls and other plant tissues such as cotyledons that came into contact with the herbicide. Occasionally these symptoms were observed at rates as low as 1 lb/A under an unspecified set of conditions occurring in the field. A combination of fluorodifen applied preemergence and cultivation two weeks after emergence of the crop provided the best weed controls Shading the crop at different stages of development did not provide an explanation for the cause of stem lesion development, but when shade was provided from application until the first true leaf, phytotoxicity was noticeable. Three soil types and two watering regimes did not provide significant, consistent phytotoxicity or stem burning. By the use of neutral density filters, different intensities of light with the same spectral emission were obtained in growth chambers. Bean and soybean plants were more sensitive to fluorodifen at low levels of light. The percentage dry weight reduction decreased as the light intensity increased from 1,000 to 2,000 ft/c. In determining the critical period in which light enhances fluorodifen injury to beans and soybeans, it was found that plants exposed to light on the second to third day after planting were most severely injured. When filters were used to evaluate the influence of light quality on fluorodifen toxicity to beans and soybeans, these plants were more sensitive to fluorodifen when exposed to yellow and red light than when exposed to blue or white light. Phytotoxic symptoms were observed especially under yellow light. Exposure to light at the time of crop emergence resulted in the greatest phytotoxicity. Autoradiography and radioassay results indicated that ¹⁴C-fluorodifen was absorbed mostly within six hours after application. The distribution pattern remained fairly constant in beans and soybeans with the largest percentage of activity remaining in the treated portion at all times. Greater mobility of the label was observed in cucumber plants with some acropetal and basipetal movement recorded from the treated leaves 12 hours after applications. Covering the treated leaf did not alter the uptake of fluorodifen in any of the three plant species. Following applications to stem and roots, a similar pattern was observed, rapid uptake but little or no mobility. The unicellular algae Chlorella was used to assess the effect of fluorodifen on photosynthesis and respiration of green plant tissues. It was found that the growth of Chlorella was severely affected by low concentrations of fluorodifen in the light. The same herbicide concentrations had no effect in the dark. Under the conditions of this study, fluorodifen caused just a slight increase in the respiration of Chlorella, while photosynthesis was severely inhibited at concentrations of 1 ppm of fluorodifen. In a separate study, the persistence of fluorodifen in soil subjected to different environmental conditions was evaluated by gas chromatography. Fluorodifen was degraded more readily under high temperatures, provided that the soil was dry. Close

• 3. [Article] The effect of 2,4'-dinitro-4-trifluoromethyldiphenylether (C-6989) on beans (Phaseolus vulgaris L.) under certain soil and light conditions

  Oregon is the largest producer of green beans for processing in the United States. Because the repeated use of a single herbicide may lead to changes in the weed population, build up of residues, and other undesirable ...

  Citation × Citation Citation Abstract Copy Title: The effect of 2,4'-dinitro-4-trifluoromethyldiphenylether (C-6989) on beans (Phaseolus vulgaris L.) under certain soil and light conditions Author: Pollak, Tomas Oregon is the largest producer of green beans for processing in the United States. Because the repeated use of a single herbicide may lead to changes in the weed population, build up of residues, and other undesirable factors, a continuous search for new herbicides is taking place. C-6989¹[superscript /] has been registered and used in soybeans; however, the response of green beans to the chemical has not been studied in detail. In this work the following factors were studied: The tolerance of beans and other plants to C-6989, site of uptake, type and site of action of the herbicide and the extent to which mechanical conditions of the soil surface is responsible for herbicidal injury to bean seedlings. An evaluation was made of the residual effects of C-6989 in rotation crops. Results indicated that the herbicide is taken up by roots, shoot or combination of both, depending upon species. Applied at high rates on beans, the effects observed were that of a contact type herbicide. It appeared to block the photosynthetic process by destroying chlorophyll pigments. Under field conditions, a rate of 4 lb/A applied preemergence controlled a broad spectrum of weeds without harmful effects to five varieties of bean. Delays in the application of the herbicide after bean planting, as well as delays in irrigation, tended to cause crop injury. The residual life appears to be short enough under summer conditions to allow the planting of rotation crops without injury. ¹[superscript /] Trade name is Preforan. Chemical name is 2, 4'-dinitro-4-trifluoromethyl-diphenylether. Title: The effect of 2,4'-dinitro-4-trifluoromethyldiphenylether (C-6989) on beans (Phaseolus vulgaris L.) under certain soil and light conditions Author: Pollak, Tomas Oregon is the largest producer of green beans for processing in the United States. Because the repeated use of a single herbicide may lead to changes in the weed population, build up of residues, and other undesirable factors, a continuous search for new herbicides is taking place. C-6989¹[superscript /] has been registered and used in soybeans; however, the response of green beans to the chemical has not been studied in detail. In this work the following factors were studied: The tolerance of beans and other plants to C-6989, site of uptake, type and site of action of the herbicide and the extent to which mechanical conditions of the soil surface is responsible for herbicidal injury to bean seedlings. An evaluation was made of the residual effects of C-6989 in rotation crops. Results indicated that the herbicide is taken up by roots, shoot or combination of both, depending upon species. Applied at high rates on beans, the effects observed were that of a contact type herbicide. It appeared to block the photosynthetic process by destroying chlorophyll pigments. Under field conditions, a rate of 4 lb/A applied preemergence controlled a broad spectrum of weeds without harmful effects to five varieties of bean. Delays in the application of the herbicide after bean planting, as well as delays in irrigation, tended to cause crop injury. The residual life appears to be short enough under summer conditions to allow the planting of rotation crops without injury. ¹[superscript /] Trade name is Preforan. Chemical name is 2, 4'-dinitro-4-trifluoromethyl-diphenylether. Close

• 4. [Article] Contamination and growth of Bacillus cereus and Clostridium perfringens in Mexican-style beans

  Because Mexican foods have been implicated in a number of outbreaks of foodborne illness in the United States, production procedures used in Mexican restaurants were investigated by interviewing four managers. ...

  Citation × Citation Citation Abstract Copy Title: Contamination and growth of Bacillus cereus and Clostridium perfringens in Mexican-style beans Author: Nester, Susan DeWitt Because Mexican foods have been implicated in a number of outbreaks of foodborne illness in the United States, production procedures used in Mexican restaurants were investigated by interviewing four managers. Two major problems identified through these interviews were failure to cool large quantities of beans rapidly and failure to reheat beans thoroughly before placement on the steam table. Experiments were designed to study the effects of varying temperatures, duration of incubation, and the location in the product as it might affect aeration on growth of B. cereus and C. perfringens, singly and combined, in cooked mashed pinto beans. Growth of both B. cereus and C. perfringens was rapid at 37°C, with numbers of cells associated with illness reached in 4 and 6 hours, respectively. B. cereus may present more of a health hazard, since obvious signs of spoilage did not occur in these beans until 12 hours, whereas C. perfringens caused obvious spoilage of beans within 6 to 8 hours. At 23°C with B. cereus, the numbers associated with illness were found at 12 hours. However, the beans appeared to be spoiled before this level was reached with C. perfringens at 24 hours. Aeration, as indicated by location in the jar, appeared to have more of an effect on B. cereus growth than on C. perfringens, but good growth of the two species occurred in both top and bottom locations. Restaurant samples of bean dip and mashed beans were analyzed for contamination with B. cereus and C. perfringens. Total aerobic and anaerobic counts were determined. Only two of the 42 samples were found to contain B. cereus or C. perfringens and these were present in low numbers. The total aerobic and anaerobic counts varied from less than 100 to 100,000,000 per gram: chiefly lactic acid bacteria which appeared to be related to the seasoning ingredients. However, one batch of bean dip and one of mashed beans were found to contain large numbers of coagulase-positive S. aureus (>100,000/g). Title: Contamination and growth of Bacillus cereus and Clostridium perfringens in Mexican-style beans Author: Nester, Susan DeWitt Because Mexican foods have been implicated in a number of outbreaks of foodborne illness in the United States, production procedures used in Mexican restaurants were investigated by interviewing four managers. Two major problems identified through these interviews were failure to cool large quantities of beans rapidly and failure to reheat beans thoroughly before placement on the steam table. Experiments were designed to study the effects of varying temperatures, duration of incubation, and the location in the product as it might affect aeration on growth of B. cereus and C. perfringens, singly and combined, in cooked mashed pinto beans. Growth of both B. cereus and C. perfringens was rapid at 37°C, with numbers of cells associated with illness reached in 4 and 6 hours, respectively. B. cereus may present more of a health hazard, since obvious signs of spoilage did not occur in these beans until 12 hours, whereas C. perfringens caused obvious spoilage of beans within 6 to 8 hours. At 23°C with B. cereus, the numbers associated with illness were found at 12 hours. However, the beans appeared to be spoiled before this level was reached with C. perfringens at 24 hours. Aeration, as indicated by location in the jar, appeared to have more of an effect on B. cereus growth than on C. perfringens, but good growth of the two species occurred in both top and bottom locations. Restaurant samples of bean dip and mashed beans were analyzed for contamination with B. cereus and C. perfringens. Total aerobic and anaerobic counts were determined. Only two of the 42 samples were found to contain B. cereus or C. perfringens and these were present in low numbers. The total aerobic and anaerobic counts varied from less than 100 to 100,000,000 per gram: chiefly lactic acid bacteria which appeared to be related to the seasoning ingredients. However, one batch of bean dip and one of mashed beans were found to contain large numbers of coagulase-positive S. aureus (>100,000/g). Close

• 5. [Article] Activated carbon for improving diuron selectivity in beans

  Activated carbon is effective in protecting beans from herbicide injury. In a field study, diuron [3-(3, 4- dichlorophenyl)- 1- 1- dimethyl urea], linuron [3- ( 3, 4- dichloropheny1)- 1- methoxy- 1- naethylurea], fluometuron ...

  Citation × Citation Citation Abstract Copy Title: Activated carbon for improving diuron selectivity in beans Author: Romero M., Carlos Eduardo Activated carbon is effective in protecting beans from herbicide injury. In a field study, diuron [3-(3, 4- dichlorophenyl)- 1- 1- dimethyl urea], linuron [3- ( 3, 4- dichloropheny1)- 1- methoxy- 1- naethylurea], fluometuron [1, 1-dimethyl- 3-(α , α, α -trifluoro- m-toly1) urea], and metobromuron [3, (2- bromophenyI)- 1- 1- rnethoxy- 1- methyl urea] we re used to determine the effectiveness of a one-inch band of activated carbon (Aqua Nuchar A) applied over the bean (Phaseolus vulgaris L.) row in protecting the crop from herbicide injury. Activated carbon was applied at 0, 150 and 300 pounds per acre, broadcast basis, while diuron, linuron, fluometuron and metobromuron were applied at rates of 1. 0 and 2. 0, 2. 0 and 4. 0, 1. 0 and 2. 0, and 1. 0 and 2. 0 lbs /acre, respectively. The results obtained showed that when activated carbon was used as a band treatment of one inch over the row (broadcast basis) at a rate of 150 pounds per acre, prior to herbicide application, good crop protection was obtained for all herbicide treatments at all rates. However, the activated carbon also protected that weeds that germinated under the carbon band. In the greenhouse, the influence of band width was determined by applying 0, 150 and 300 pounds per acre of carbon in bands of 1.0 and 3.0 inches in width. A carbon band of 1.0 inch provided adequate protection to the beans for all rates tested. No injury was observed in either the roots or the shoots, for all rates tested. The effectiveness of activated carbon in protecting four plant species, beans, ryegrass (Lolium perenne Var. Linn L.), pigweed Amaranthus retroflexus L.) and barnyardgrass (Echinochloa crusgalli (L) Beauv) from diuron injury was also determined in a greenhouse experiment. It was found that activated carbon to diuron ratios of 100:1 were effective in protecting the four species tested. Experiments with 2-gram "packets" of vermiculite with carbon showed that beans were protected from diuron injury only when the packet contained carbon. Application of activated carbon mixed in with a vermiculite "packet" was as effective as applying the carbon in a one-inch band over the row. In an experiment involving alternate wetting and drying of activated carbon no decrease of the adsorptive capacity of the carbon was observed. In the laboratory the adsorption of diuron at 7, 10 and 20 ppm by four commercial types of activated carbon (Aqua Nuchar A, Darco-M, Gro-Safe and Pittsburg No. 3) was determined. The results indicated that differences exist between different carbon sources. The greater the surface area of the carbon, the greater its adsorptivity. Desorption studies with diuron at 20 ppm and four different activated carbon sources showed that the degree of desorption also varied between the carbon sources. Title: Activated carbon for improving diuron selectivity in beans Author: Romero M., Carlos Eduardo Activated carbon is effective in protecting beans from herbicide injury. In a field study, diuron [3-(3, 4- dichlorophenyl)- 1- 1- dimethyl urea], linuron [3- ( 3, 4- dichloropheny1)- 1- methoxy- 1- naethylurea], fluometuron [1, 1-dimethyl- 3-(α , α, α -trifluoro- m-toly1) urea], and metobromuron [3, (2- bromophenyI)- 1- 1- rnethoxy- 1- methyl urea] we re used to determine the effectiveness of a one-inch band of activated carbon (Aqua Nuchar A) applied over the bean (Phaseolus vulgaris L.) row in protecting the crop from herbicide injury. Activated carbon was applied at 0, 150 and 300 pounds per acre, broadcast basis, while diuron, linuron, fluometuron and metobromuron were applied at rates of 1. 0 and 2. 0, 2. 0 and 4. 0, 1. 0 and 2. 0, and 1. 0 and 2. 0 lbs /acre, respectively. The results obtained showed that when activated carbon was used as a band treatment of one inch over the row (broadcast basis) at a rate of 150 pounds per acre, prior to herbicide application, good crop protection was obtained for all herbicide treatments at all rates. However, the activated carbon also protected that weeds that germinated under the carbon band. In the greenhouse, the influence of band width was determined by applying 0, 150 and 300 pounds per acre of carbon in bands of 1.0 and 3.0 inches in width. A carbon band of 1.0 inch provided adequate protection to the beans for all rates tested. No injury was observed in either the roots or the shoots, for all rates tested. The effectiveness of activated carbon in protecting four plant species, beans, ryegrass (Lolium perenne Var. Linn L.), pigweed Amaranthus retroflexus L.) and barnyardgrass (Echinochloa crusgalli (L) Beauv) from diuron injury was also determined in a greenhouse experiment. It was found that activated carbon to diuron ratios of 100:1 were effective in protecting the four species tested. Experiments with 2-gram "packets" of vermiculite with carbon showed that beans were protected from diuron injury only when the packet contained carbon. Application of activated carbon mixed in with a vermiculite "packet" was as effective as applying the carbon in a one-inch band over the row. In an experiment involving alternate wetting and drying of activated carbon no decrease of the adsorptive capacity of the carbon was observed. In the laboratory the adsorption of diuron at 7, 10 and 20 ppm by four commercial types of activated carbon (Aqua Nuchar A, Darco-M, Gro-Safe and Pittsburg No. 3) was determined. The results indicated that differences exist between different carbon sources. The greater the surface area of the carbon, the greater its adsorptivity. Desorption studies with diuron at 20 ppm and four different activated carbon sources showed that the degree of desorption also varied between the carbon sources. Close