The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Tracy M Sterling - One of the best experts on this subject based on the ideXlab platform.
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ethylene is not involved in clopyralid action in yellow starthistle centaurea solstitialis l
Pesticide Biochemistry and Physiology, 2002Co-Authors: Juan M Valenzuelavalenzuela, Norman K Lownds, Tracy M SterlingAbstract:Abstract Auxinic herbicides often increase ethylene production in susceptible but not resistant plants. Thus, a role for ethylene biosynthesis in the resistance to, and mode of action of, auxinic herbicides has been suggested. Experiments were conducted to determine the role of ethylene production induced by clopyralid (3,6-dichloro-2-pyridine carboxylic acid) in the mode of action of, and cross-resistance to, this herbicide in picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid)-susceptible (S) and -resistant (R) yellow starthistle ( Centaurea solstitialis L.) plants. Foliar-applied clopyralid induced ethylene production, Epinasty, and necrosis in S but had no effect on R. Wounding induced ethylene production in both S and R, so R possesses a functional ethylene biosynthesis pathway. Aminoethoxyvinylglycine (AVG), an ethylene synthesis inhibitor, inhibited ethylene production in S; however, clopyralid-induced Epinasty, necrosis, and shoot weight reduction were not prevented. Therefore, herbicide damage was not attributable to induced ethylene. In addition, silver thiosulfate (STS), an ethylene action inhibitor, did not alter herbicide damage. Foliar-applied ethephon, an ethylene-releasing compound, increased ethylene released from S and R, but did not visibly affect plants. Exogenous-applied ethylene in a flow-through system for 48 h did not induce morphological symptoms in plants at 0 or 250 μL L −1 ; at 500 μL L −1 and greater ethylene induced slight leaf rolling and wilting in both accessions although there was no effect on plant weight 3 weeks after treatment. The low sensitivity to exogenously applied ethylene and the inability of AVG and STS to block any symptoms induced by clopyralid suggest that ethylene is a symptom, not a mediator, of auxinic herbicide action and resistance in yellow starthistle.
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effect of picloram on resistant and susceptible yellow starthistle centaurea solstitialis the role of ethylene
Weed Science, 1998Co-Authors: Robert P Sabba, Tracy M Sterling, Norman K LowndsAbstract:Norm K. Lownds Department of Horticulture, Michigan State University, East Lansing, MI 48824; lownds@pilot.msu.edu The noxious weed yellow starthistle is commonly controlled by the auxinic herbicide picloram. Induction of ethylene synthesis, Epinasty, and reduction in shoot growth are typical symptoms of picloram treatment. Picloram did not induce ethylene evolution in the resistant accession RDW-1, though it caused a 250% increase in ethylene evolution in the susceptible wildtype SCI-1. The ethylene synthesis inhibitor aminoethoxyvinylglycine reduced the amount of ethylene induced by picloram in SCI-1 to control levels, but only reduced Epinasty by 20% after 6 d. Aminoethoxyvinylglycine did not affect the reduction in shoot weight caused by picloram. The ethylene-releasing compound ethephon induced only a small amount of Epinasty and had little effect on shoot weight in either accession. These results suggest that ethylene induced by picloram in wildtype plants plays only a minor role in the herbicidal effects of picloram. Furthermore, the resistance of the RDW-1 accession is not due to the lack of ethylene biosynthesis following picloram application to this accession.
Michael B. Jackson - One of the best experts on this subject based on the ideXlab platform.
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transport of 1 aminocyclopropane 1 carboxylic acid acc in the transpiration stream of tomato lycopersicon esculentum in relation to foliar ethylene production and petiole Epinasty
Australian Journal of Plant Physiology, 1998Co-Authors: Mark A Else, Michael B. JacksonAbstract:We investigated the concentration and delivery of 1-aminocyclopropane-1-carboxylic acid (ACC) in the transpiration stream of flooded and well-drained 1-month-old tomato plants (Lycopersicon esculentum Mill. cv. Ailsa Craig) over time in parallel with foliar ethylene production and petiole Epinasty. ACC was measured by gas chromatography using a nitrogen–phosphorus detector. Before analysis, roots of freshly detopped plants were pressurised pneumatically to make xylem sap flow at rates similar to those of whole plant transpiration. Delivery of ACC from roots to shoots of well-drained plants was sufficient to support basal ethylene production in shoots of unstressed plants. Delivery from flooded, oxygen-deficient, roots increased after 6 h and coincided with the onset of epinastic leaf curvature. Further increases in ACC delivery and epinastic curvature occurred later in the photoperiod. After 24 h flooding, ACC delivery in xylem sap was 28 times more than in well-drained plants. This increased export of ACC from flooded roots was more than sufficient to account for the extra ethylene production in the shoots and coincided with ACC accumulation in the leaves. Removing the shoot before flooding did not reduce ACC export from oxygen-deficient roots indicating that the ACC originated in roots and not the shoot. Increased ethylene production in petioles of flooded plants lagged 18 h behind Epinasty.
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The Use of Antisense Transgenic Tomato Plants to Study the Role of Ethylene in Responses to Waterlogging
Cellular and Molecular Aspects of the Plant Hormone Ethylene, 1993Co-Authors: P. J. English, Grantley W. Lycett, Jeremy A. Roberts, K. C. Hall, Michael B. JacksonAbstract:Fruit of tomato plants transformed with an antisense construct to the ripening-related cDNA clone, pTOM13, demonstrate a reduced capacity to produce ethylene. Recent work shows that this is because the clone encodes for one form of the ethylene forming enzyme (EFE) (Hamilton et al.,1991). Ethylene is thought to mediate in several developmental effects, such as petiole Epinasty and adventitious root formation, when plants are exposed to waterlogged conditions (Jackson, 1985). This hypothesis would be supported if the expected reduced capacity for ethylene production in vegetative tissue of antisense plants was associated with a diminution of the physiological responses to waterlogging. Thus, the pTOM13 antisense transformants may serve as a powerful tool for investigating ethylene action in waterlogged plants. We have studied the extent to which Epinasty, ethylene production and the accumulation of ACC and bound (putative malonyl) ACC in waterlogged plants is affected by pTOM13 antisense transformation of the tomato cultivar ‘Ailsa Craig’.
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effects of mecoprop an auxin analogue on ethylene evolution and Epinasty in two biotypes of stellaria media
Annals of Botany, 1991Co-Authors: D Coupland, Michael B. JacksonAbstract:This paper investigates whether susceptible and resistant biotypes differ in their responses to mecoprop. If so, this would suggest an inherent difference at an early step in the action of the herbicide and may help to explain the resistance mechanism. Ethylene production and foliar Epinasty were considered suitable parameters for study since both are stimulated by non-phytotoxic concentrations of mecoprop, or chemically similar auxins
Juan M Valenzuelavalenzuela - One of the best experts on this subject based on the ideXlab platform.
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ethylene is not involved in clopyralid action in yellow starthistle centaurea solstitialis l
Pesticide Biochemistry and Physiology, 2002Co-Authors: Juan M Valenzuelavalenzuela, Norman K Lownds, Tracy M SterlingAbstract:Abstract Auxinic herbicides often increase ethylene production in susceptible but not resistant plants. Thus, a role for ethylene biosynthesis in the resistance to, and mode of action of, auxinic herbicides has been suggested. Experiments were conducted to determine the role of ethylene production induced by clopyralid (3,6-dichloro-2-pyridine carboxylic acid) in the mode of action of, and cross-resistance to, this herbicide in picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid)-susceptible (S) and -resistant (R) yellow starthistle ( Centaurea solstitialis L.) plants. Foliar-applied clopyralid induced ethylene production, Epinasty, and necrosis in S but had no effect on R. Wounding induced ethylene production in both S and R, so R possesses a functional ethylene biosynthesis pathway. Aminoethoxyvinylglycine (AVG), an ethylene synthesis inhibitor, inhibited ethylene production in S; however, clopyralid-induced Epinasty, necrosis, and shoot weight reduction were not prevented. Therefore, herbicide damage was not attributable to induced ethylene. In addition, silver thiosulfate (STS), an ethylene action inhibitor, did not alter herbicide damage. Foliar-applied ethephon, an ethylene-releasing compound, increased ethylene released from S and R, but did not visibly affect plants. Exogenous-applied ethylene in a flow-through system for 48 h did not induce morphological symptoms in plants at 0 or 250 μL L −1 ; at 500 μL L −1 and greater ethylene induced slight leaf rolling and wilting in both accessions although there was no effect on plant weight 3 weeks after treatment. The low sensitivity to exogenously applied ethylene and the inability of AVG and STS to block any symptoms induced by clopyralid suggest that ethylene is a symptom, not a mediator, of auxinic herbicide action and resistance in yellow starthistle.
Norman K Lownds - One of the best experts on this subject based on the ideXlab platform.
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ethylene is not involved in clopyralid action in yellow starthistle centaurea solstitialis l
Pesticide Biochemistry and Physiology, 2002Co-Authors: Juan M Valenzuelavalenzuela, Norman K Lownds, Tracy M SterlingAbstract:Abstract Auxinic herbicides often increase ethylene production in susceptible but not resistant plants. Thus, a role for ethylene biosynthesis in the resistance to, and mode of action of, auxinic herbicides has been suggested. Experiments were conducted to determine the role of ethylene production induced by clopyralid (3,6-dichloro-2-pyridine carboxylic acid) in the mode of action of, and cross-resistance to, this herbicide in picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid)-susceptible (S) and -resistant (R) yellow starthistle ( Centaurea solstitialis L.) plants. Foliar-applied clopyralid induced ethylene production, Epinasty, and necrosis in S but had no effect on R. Wounding induced ethylene production in both S and R, so R possesses a functional ethylene biosynthesis pathway. Aminoethoxyvinylglycine (AVG), an ethylene synthesis inhibitor, inhibited ethylene production in S; however, clopyralid-induced Epinasty, necrosis, and shoot weight reduction were not prevented. Therefore, herbicide damage was not attributable to induced ethylene. In addition, silver thiosulfate (STS), an ethylene action inhibitor, did not alter herbicide damage. Foliar-applied ethephon, an ethylene-releasing compound, increased ethylene released from S and R, but did not visibly affect plants. Exogenous-applied ethylene in a flow-through system for 48 h did not induce morphological symptoms in plants at 0 or 250 μL L −1 ; at 500 μL L −1 and greater ethylene induced slight leaf rolling and wilting in both accessions although there was no effect on plant weight 3 weeks after treatment. The low sensitivity to exogenously applied ethylene and the inability of AVG and STS to block any symptoms induced by clopyralid suggest that ethylene is a symptom, not a mediator, of auxinic herbicide action and resistance in yellow starthistle.
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effect of picloram on resistant and susceptible yellow starthistle centaurea solstitialis the role of ethylene
Weed Science, 1998Co-Authors: Robert P Sabba, Tracy M Sterling, Norman K LowndsAbstract:Norm K. Lownds Department of Horticulture, Michigan State University, East Lansing, MI 48824; lownds@pilot.msu.edu The noxious weed yellow starthistle is commonly controlled by the auxinic herbicide picloram. Induction of ethylene synthesis, Epinasty, and reduction in shoot growth are typical symptoms of picloram treatment. Picloram did not induce ethylene evolution in the resistant accession RDW-1, though it caused a 250% increase in ethylene evolution in the susceptible wildtype SCI-1. The ethylene synthesis inhibitor aminoethoxyvinylglycine reduced the amount of ethylene induced by picloram in SCI-1 to control levels, but only reduced Epinasty by 20% after 6 d. Aminoethoxyvinylglycine did not affect the reduction in shoot weight caused by picloram. The ethylene-releasing compound ethephon induced only a small amount of Epinasty and had little effect on shoot weight in either accession. These results suggest that ethylene induced by picloram in wildtype plants plays only a minor role in the herbicidal effects of picloram. Furthermore, the resistance of the RDW-1 accession is not due to the lack of ethylene biosynthesis following picloram application to this accession.
Pardeep Kumar - One of the best experts on this subject based on the ideXlab platform.
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Malus pumila ‘Spy 227’ and Apple stem pitting virus: graft incompatibility and Epinasty
VirusDisease, 2015Co-Authors: Ajay Brakta, Anil Handa, P. D. Thakur, Manica Tomar, Pardeep KumarAbstract:Apple stem pitting foveavirus (ASPV) is one of the most important and widespread virus infecting apples in the world. Of late, the virus has been found to be invariably associated with most of the apple plantations of Shimla district of Himachal Pradesh based on DAS-ELISA results. Bioassay of viruses in vegetatively propagated crops including apple is considered to be an essential component in indexing programmes for the production of virus free propagating material. Woody indicator Malus pumila ‘ Spy 227’ was used for the detection of ASPV through double grafting method. Graft incompatibility and Epinasty symptoms were observed on Malus pumila Spy 227 indicator plants. Further, molecular identification of the virus isolate was done by cloning and sequencing of the test isolate. Partial sequence analysis of the coat protein gene showed 89 % nucleotide identity in BLASTN analysis with ASPV isolate from China (Accession No. JF895517). This is the first record of ASPV producing Graft incompatibility on Spy 227 indicator plants.
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Malus pumila 'Spy 227' and Apple stem pitting virus: graft incompatibility and Epinasty.
Virusdisease, 2015Co-Authors: Ajay Brakta, Anil Handa, P. D. Thakur, Manica Tomar, Pardeep KumarAbstract:Apple stem pitting foveavirus (ASPV) is one of the most important and widespread virus infecting apples in the world. Of late, the virus has been found to be invariably associated with most of the apple plantations of Shimla district of Himachal Pradesh based on DAS-ELISA results. Bioassay of viruses in vegetatively propagated crops including apple is considered to be an essential component in indexing programmes for the production of virus free propagating material. Woody indicator Malus pumila ‘Spy 227’ was used for the detection of ASPV through double grafting method. Graft incompatibility and Epinasty symptoms were observed on Malus pumila Spy 227 indicator plants. Further, molecular identification of the virus isolate was done by cloning and sequencing of the test isolate. Partial sequence analysis of the coat protein gene showed 89 % nucleotide identity in BLASTN analysis with ASPV isolate from China (Accession No. JF895517). This is the first record of ASPV producing Graft incompatibility on Spy 227 indicator plants.