Amaranthus retroflexus L. is a serious and widespread malignant weed in soybean fields in Heilongjiang Province. Exploring the dormancy characteristics of A. retroflexus L. seeds and the physiological response of its ...Amaranthus retroflexus L. is a serious and widespread malignant weed in soybean fields in Heilongjiang Province. Exploring the dormancy characteristics of A. retroflexus L. seeds and the physiological response of its seedlings to acifluorfen sodium can provide a basis for further researches on its resistance mechanism. Using newly harvested and stored A. retroflexus L. seeds for one year as experimental materials, the effects of different concentrations of HCl, NaOH, water temperature, gibberellic acid(GA) and polyethylene glycol(PEG) on the dormancy and germination of A. retroflexus L. seeds were studied. The sensitivity of A. retroflexus L.to acifluorfen sodium was determined using bioassay. The effects on leaf chlorophyll content and target enzyme activity were studied at a normal dosage of 360 g a.i. hm^(-2) and a doubling dosage of 720 g a.i. hm^(-2) of acifluorfen sodium. Newly harvested seeds exhibiting dormancy were soaked in water of various temperatures and in different concentrations of NaOH and HCl, which were ineffective in breaking the seed dormancy. GA could break seed dormancy, and the highest seed germination rate reached 93.33% when they were soaked at 3 000 mg·L^(-1) for 72 h and 4 000 mg·L^(-1) for 48 h. The drought stress was simulated with a 15%-25% polyethylene glycol solution, which had no significant effect on the seed germination rate. The GR_(50) value of acifluorfen sodium for A. retroflexus L. was 705.7 g a.i. hm^(-2), which was 1.96 times the recommended dose in the field. After the application of different doses of acifluorfen sodium, the chlorophyll content of A. retroflexus L. reached its minimum value 3 days after treatment(DAT), and then gradually increased. The activity of the target enzyme protoporphyrinogen oxidase(PPO) reached the highest value at 7 DAT under different dosages, and gradually returned to normal levels thereafter. Soaking with gibberellin was an effective method to break seed dormancy. A. retroflexus L. seeds had certain drought resistance during the germination process. A. retroflexus L. was not sensitive to acifluorfen sodium and acifluorfen sodium ether, and could not effectively inhibit the PPO activity, indicating that A. retroflexus L. had target resistance to acifluorfen sodium.展开更多
A metabolite, which had an inhibitory effect on plant growth, was isolated from cultural filtrate of Botrytis cinerea isolate BC4 by column chromatography on silica gel and preparative HPLC. Its structure was determin...A metabolite, which had an inhibitory effect on plant growth, was isolated from cultural filtrate of Botrytis cinerea isolate BC4 by column chromatography on silica gel and preparative HPLC. Its structure was determined from HPLC-ESI MS, GC, IR, ^1H NMR and ^13C NMR spectral data, as well as chemical hydrolysis. The results showed that this metabolite was quite similar to abscisic acid-β-D-glucopyranosyl ester（ABAGE） in structure. The inhibitory effect of the ABAGE-like metabolite on plant growth was investigated using a weed Amaranthus retroflexus L. as a bioassay material. The results showed that it inhibited hypocotyls and roots growth of A. retroflexus （Amaranthus retroflexus L.） seedlings when its concentration was over 0.5 μM. The concentrations for 50% inhibition of hypocotyls and roots growth of A. retroflexus seedlings were 2.8 and 1.4 μM, respectively.展开更多
Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its ...Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its effects on seed germination, seedling growth, morphological and physiological characteristics of Amaranthus retroflexus. Drupacine inhibited seed germination and seedling growth, and had a median inhibition concentration(IC50) value of 38.99 mg L-1against A. retroflexus root. The α-amylase activity and soluble sugar content in treated plants were significantly lower than that of the control. The expression of α-amylase gene was dosage-dependently inhibited compared to the untreated control. This suggested that inhibition of α-amylase activity was a mode of action on seed germination. The root hairs were significantly decreased and part of the root cap fell off after treatment with drupacine. The ultrastructure observation showed that cell damage of root tips increased with the treatment time. Drupacine also increased the relative conductivity and malondialdehyde(MDA) content. Peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) activities were significantly enhanced in the treatment compared to the control. These findings indicated that the physiological and biochemical reaction changes leading to morphological and membrane injuries were the main effects of drupacine on the inhibition of seedling growth. Drupacine can be developed as a botanical herbicide.展开更多
A phytotoxin from Xanthomonas campestris pv. retroflexus was isolated using a chromatographer and HPLC, and the components were identified to be a mixture of minor molecular compounds including organic acids and cyclo...A phytotoxin from Xanthomonas campestris pv. retroflexus was isolated using a chromatographer and HPLC, and the components were identified to be a mixture of minor molecular compounds including organic acids and cyclo-（proline-phenylalanine）. The greenhouse cultivation test was used to determine the influence of the isolated fractions on the growth of target weed redroot pigweed （Amaranthus retroflexus L）. The experimental results demonstrated that the cyclo-（Pro-Phe） had the weed inhibit activity obviously on dicotyledonous weed and the mixture with six organic acids showed stronger bioactivity. Further, greenhouse and field test were processed, and the test showed that the use of the toxin appeared to have the potential to be developed further as a bioherbicide system to control weedy grasses.展开更多
Aimed at finding out natural compounds to kill weeds, a plant pathogenic fungus, Botrytis cinerea isolate BC4, was chosen as a source. A significantly polar metabolite, which was different in chromatographic behavior ...Aimed at finding out natural compounds to kill weeds, a plant pathogenic fungus, Botrytis cinerea isolate BC4, was chosen as a source. A significantly polar metabolite, which was different in chromatographic behavior from ABAGE-like metabolite, was isolated from cultural filtrate of the fungus by column chromatography on silica gel, preparative LC, TLC and HPLC. The structure of the metabolite was determined by HPLC-ESI MS, g.l.c, IR, ^1H NMR and hydrolysis. The results showed that this metabolite was quite similar with ABAGS. The bioassay showed the metabolite had inhibition to seed germination of both broadleaf weeds [Amaranthus retroflerus L. and Chenopodium album L.] and gramineae weeds [Digitaria sanguinalis L. Scop and Echinochloa crusgalii L. Beauv]. It also had inhibitory activity to the seedling growth of broadleaf weeds. The bioassay, using Amaranthus retroflexus L. as an indicator, showed that the lowest concentration of the metabolite to inhibit root＋sprout growth of A. retroflexus was 0.6 μM, and the concentration for 50% inhibition was 1.3μM.展开更多
Redroot pigweed (Amaranthus retroflexus L.) is a nuisance weed that affects cotton (Gossypium hirsutum L.) growth and yield worldwide. Being able to distinguish redroot pigweed from cotton would help producers and cro...Redroot pigweed (Amaranthus retroflexus L.) is a nuisance weed that affects cotton (Gossypium hirsutum L.) growth and yield worldwide. Being able to distinguish redroot pigweed from cotton would help producers and crop consultants better implement strategies used to suppress and control it. Hyperspectral reflectance properties of weed and crop canopies have been used to differentiate between them. Currently, no information is available on the application of hyperspectral data to distinguish redroot pigweed from cotton with different leaf shapes. Positive results will further support the exploration of remote sensing technology for distinguishing redroot pigweed from cotton. The objectives were to compare canopy hyperspectral reflectance of redroot pigweed to canopy hyperspectral reflectance of okra and super okra leaf cotton and to identify regions of the spectrum in which differences exist in their reflectance properties. Hyperspectral reflectance measurements of redroot pigweed and cotton were obtained with a spectroradimeter on May 6 and June 27, 2019. Plants grown in a greenhouse were used for this study. One-hundred and sixty-two 10-nm bands (400 - 2350 nm spectral range) were evaluated with analysis of variance (p ≤ 0.05) and Dunnett’s test (p ≤ 0.05) to determine the wavebands that were useful for separating redroot pigweed from okra leaf and super okra leaf cotton. The following bands were consistent in distinguishing redroot pigweed and okra leaf cotton on both dates: 420 nm, 510 - 650 nm, 690 - 740 nm, and 2000 - 2010 nm;whereas, 400 - 500 nm, 1480 - 1780 nm, and 1990 - 2350 nm were identified for both dates for separating redroot pigweed from super okra leaf cotton. Commercial imaging systems used on ground-based or airborne platforms can be easily tuned into the spectral bands listed in this study, thus providing managers with a tool to use for identifying redroot pigweed in cotton production systems.展开更多
During the last ice age, CO2 concentration （[CO2]） was 180-200 umol/mol compared with the modern value of 380 umol/mol, and global temperatures were -8 ℃ cooler. Relatively little is known about the responses of C3...During the last ice age, CO2 concentration （[CO2]） was 180-200 umol/mol compared with the modern value of 380 umol/mol, and global temperatures were -8 ℃ cooler. Relatively little is known about the responses of C3 and C4 species to longterm exposure to glacial conditions. Here Abutilon theophrasti Medik. （C3） and Amaranthus retroflexus L. （C4） were grown at 200 umol/mol CO2 with current （30/24℃） and glacial （22/16℃） temperatures for 22d. Overall, the C4 species exhibited a large growth advantage over the C3 species at low [CO2]. However, this advantage was reduced at low temperature, where the C4 species produced 5x the total mass of the C3 species versus 14x at the high temperature. This difference was due to a reduction in C4 growth at low temperature, since the C3 species exhibited similar growth between temperatures. Physiological differences between temperatures were not detected for either species, although photorespiration/net photosynthesis was reduced in the C3 species grown at low temperature, suggesting evidence of improved carbon balance at this treatment. This system suggests that C4 species had a growth advantage over C3 species during low [CO2] of the last ice age, although concurrent reductions in temperatures may have reduced this advantage.展开更多
基金Supported by the National Major Special Project for the Cultivation of New Genetically Modified Biological Varieties(Topic ZX08011-003)。
文摘Amaranthus retroflexus L. is a serious and widespread malignant weed in soybean fields in Heilongjiang Province. Exploring the dormancy characteristics of A. retroflexus L. seeds and the physiological response of its seedlings to acifluorfen sodium can provide a basis for further researches on its resistance mechanism. Using newly harvested and stored A. retroflexus L. seeds for one year as experimental materials, the effects of different concentrations of HCl, NaOH, water temperature, gibberellic acid(GA) and polyethylene glycol(PEG) on the dormancy and germination of A. retroflexus L. seeds were studied. The sensitivity of A. retroflexus L.to acifluorfen sodium was determined using bioassay. The effects on leaf chlorophyll content and target enzyme activity were studied at a normal dosage of 360 g a.i. hm^(-2) and a doubling dosage of 720 g a.i. hm^(-2) of acifluorfen sodium. Newly harvested seeds exhibiting dormancy were soaked in water of various temperatures and in different concentrations of NaOH and HCl, which were ineffective in breaking the seed dormancy. GA could break seed dormancy, and the highest seed germination rate reached 93.33% when they were soaked at 3 000 mg·L^(-1) for 72 h and 4 000 mg·L^(-1) for 48 h. The drought stress was simulated with a 15%-25% polyethylene glycol solution, which had no significant effect on the seed germination rate. The GR_(50) value of acifluorfen sodium for A. retroflexus L. was 705.7 g a.i. hm^(-2), which was 1.96 times the recommended dose in the field. After the application of different doses of acifluorfen sodium, the chlorophyll content of A. retroflexus L. reached its minimum value 3 days after treatment(DAT), and then gradually increased. The activity of the target enzyme protoporphyrinogen oxidase(PPO) reached the highest value at 7 DAT under different dosages, and gradually returned to normal levels thereafter. Soaking with gibberellin was an effective method to break seed dormancy. A. retroflexus L. seeds had certain drought resistance during the germination process. A. retroflexus L. was not sensitive to acifluorfen sodium and acifluorfen sodium ether, and could not effectively inhibit the PPO activity, indicating that A. retroflexus L. had target resistance to acifluorfen sodium.
基金the Natural ScienceFoundation of Shaanxi Province(142101)of China,the Key Project of Science and Technology of HebeiProvince Project of Agriculture Key Problem of Shaanxi Province(2003K03-G2-03) 9816 KeyProject of Hebei Agricultural University.
文摘A metabolite, which had an inhibitory effect on plant growth, was isolated from cultural filtrate of Botrytis cinerea isolate BC4 by column chromatography on silica gel and preparative HPLC. Its structure was determined from HPLC-ESI MS, GC, IR, ^1H NMR and ^13C NMR spectral data, as well as chemical hydrolysis. The results showed that this metabolite was quite similar to abscisic acid-β-D-glucopyranosyl ester（ABAGE） in structure. The inhibitory effect of the ABAGE-like metabolite on plant growth was investigated using a weed Amaranthus retroflexus L. as a bioassay material. The results showed that it inhibited hypocotyls and roots growth of A. retroflexus （Amaranthus retroflexus L.） seedlings when its concentration was over 0.5 μM. The concentrations for 50% inhibition of hypocotyls and roots growth of A. retroflexus seedlings were 2.8 and 1.4 μM, respectively.
基金funded by the Provincial Natural Science Foundation of Hebei for Excellent Young Scholar, China (C2021204071)the Science and Technology Project of Hebei Education Department (QN2021079)+1 种基金the Key Research and Development Project of Hebei Province (21326511D and 19226504D)the China Agriculture Research System of MOF and MARA (CARS-02)。
文摘Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its effects on seed germination, seedling growth, morphological and physiological characteristics of Amaranthus retroflexus. Drupacine inhibited seed germination and seedling growth, and had a median inhibition concentration(IC50) value of 38.99 mg L-1against A. retroflexus root. The α-amylase activity and soluble sugar content in treated plants were significantly lower than that of the control. The expression of α-amylase gene was dosage-dependently inhibited compared to the untreated control. This suggested that inhibition of α-amylase activity was a mode of action on seed germination. The root hairs were significantly decreased and part of the root cap fell off after treatment with drupacine. The ultrastructure observation showed that cell damage of root tips increased with the treatment time. Drupacine also increased the relative conductivity and malondialdehyde(MDA) content. Peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) activities were significantly enhanced in the treatment compared to the control. These findings indicated that the physiological and biochemical reaction changes leading to morphological and membrane injuries were the main effects of drupacine on the inhibition of seedling growth. Drupacine can be developed as a botanical herbicide.
基金Supported by the National Natural Science Fotmdation of China （No.30370939）, Natural Science Foundation of Zhejiang Province （No.300054） and Science Research Plan of Zhejiang Province （No.2004C22005）.
文摘A phytotoxin from Xanthomonas campestris pv. retroflexus was isolated using a chromatographer and HPLC, and the components were identified to be a mixture of minor molecular compounds including organic acids and cyclo-（proline-phenylalanine）. The greenhouse cultivation test was used to determine the influence of the isolated fractions on the growth of target weed redroot pigweed （Amaranthus retroflexus L）. The experimental results demonstrated that the cyclo-（Pro-Phe） had the weed inhibit activity obviously on dicotyledonous weed and the mixture with six organic acids showed stronger bioactivity. Further, greenhouse and field test were processed, and the test showed that the use of the toxin appeared to have the potential to be developed further as a bioherbicide system to control weedy grasses.
基金This research was supported by the Natural Science Foundation of Shaanxi Province，P．R．China(142101)the Key Project of Science and Technology of Hebei Province．PR．China．the Project of Agriculture Key Problem of Shaanxi Province．P．R．China(2003K03一 G2-031 and 981 6 Key Project of Hebei Agricultural University．
文摘Aimed at finding out natural compounds to kill weeds, a plant pathogenic fungus, Botrytis cinerea isolate BC4, was chosen as a source. A significantly polar metabolite, which was different in chromatographic behavior from ABAGE-like metabolite, was isolated from cultural filtrate of the fungus by column chromatography on silica gel, preparative LC, TLC and HPLC. The structure of the metabolite was determined by HPLC-ESI MS, g.l.c, IR, ^1H NMR and hydrolysis. The results showed that this metabolite was quite similar with ABAGS. The bioassay showed the metabolite had inhibition to seed germination of both broadleaf weeds [Amaranthus retroflerus L. and Chenopodium album L.] and gramineae weeds [Digitaria sanguinalis L. Scop and Echinochloa crusgalii L. Beauv]. It also had inhibitory activity to the seedling growth of broadleaf weeds. The bioassay, using Amaranthus retroflexus L. as an indicator, showed that the lowest concentration of the metabolite to inhibit root＋sprout growth of A. retroflexus was 0.6 μM, and the concentration for 50% inhibition was 1.3μM.
文摘Redroot pigweed (Amaranthus retroflexus L.) is a nuisance weed that affects cotton (Gossypium hirsutum L.) growth and yield worldwide. Being able to distinguish redroot pigweed from cotton would help producers and crop consultants better implement strategies used to suppress and control it. Hyperspectral reflectance properties of weed and crop canopies have been used to differentiate between them. Currently, no information is available on the application of hyperspectral data to distinguish redroot pigweed from cotton with different leaf shapes. Positive results will further support the exploration of remote sensing technology for distinguishing redroot pigweed from cotton. The objectives were to compare canopy hyperspectral reflectance of redroot pigweed to canopy hyperspectral reflectance of okra and super okra leaf cotton and to identify regions of the spectrum in which differences exist in their reflectance properties. Hyperspectral reflectance measurements of redroot pigweed and cotton were obtained with a spectroradimeter on May 6 and June 27, 2019. Plants grown in a greenhouse were used for this study. One-hundred and sixty-two 10-nm bands (400 - 2350 nm spectral range) were evaluated with analysis of variance (p ≤ 0.05) and Dunnett’s test (p ≤ 0.05) to determine the wavebands that were useful for separating redroot pigweed from okra leaf and super okra leaf cotton. The following bands were consistent in distinguishing redroot pigweed and okra leaf cotton on both dates: 420 nm, 510 - 650 nm, 690 - 740 nm, and 2000 - 2010 nm;whereas, 400 - 500 nm, 1480 - 1780 nm, and 1990 - 2350 nm were identified for both dates for separating redroot pigweed from super okra leaf cotton. Commercial imaging systems used on ground-based or airborne platforms can be easily tuned into the spectral bands listed in this study, thus providing managers with a tool to use for identifying redroot pigweed in cotton production systems.
基金Supported by the US Department of Energy (DE-FG02-95ER62124)the US National Science Foundation (0517668 and 0746822)an American Fellowship to JK Ward from the American Association of University Women Educational Foundation.
文摘During the last ice age, CO2 concentration （[CO2]） was 180-200 umol/mol compared with the modern value of 380 umol/mol, and global temperatures were -8 ℃ cooler. Relatively little is known about the responses of C3 and C4 species to longterm exposure to glacial conditions. Here Abutilon theophrasti Medik. （C3） and Amaranthus retroflexus L. （C4） were grown at 200 umol/mol CO2 with current （30/24℃） and glacial （22/16℃） temperatures for 22d. Overall, the C4 species exhibited a large growth advantage over the C3 species at low [CO2]. However, this advantage was reduced at low temperature, where the C4 species produced 5x the total mass of the C3 species versus 14x at the high temperature. This difference was due to a reduction in C4 growth at low temperature, since the C3 species exhibited similar growth between temperatures. Physiological differences between temperatures were not detected for either species, although photorespiration/net photosynthesis was reduced in the C3 species grown at low temperature, suggesting evidence of improved carbon balance at this treatment. This system suggests that C4 species had a growth advantage over C3 species during low [CO2] of the last ice age, although concurrent reductions in temperatures may have reduced this advantage.
