Paclobutrazol is a plant growth regulator belonging to the triazole chemical class (U.S. EPA, 2007B). Paclobutrazol was first registered by U.S. EPA in 1985. At the time of preparation of this review in 2011, PBZ was undergoing registration review by U.S. EPA to determine whether it continues to meet the FIFRA standard for registration . As part of the registration review process, a summary document was issued. This document includes a factsheet describing the Environmental Fate of Paclobutrazol.
Paclobutrazol(CAS NO:76738-62-0) has been characterized as a compound with a moderate potential for mobility in soil and water environments. The summary document for registration review prepared by U.S. EPA documents that laboratory batch equilibrium studies indicated that this chemical has the capacity to be mobile under certain conditions. Studies with nine US soils ranging in texture from sand to silt loam indicated values for the soil adsorption coefficient KD in the range from 1.3 to 23.0 ml/g.
Adsorption appeared to increase with an increase in soil organic matter content and a decrease in soil pH. In the draft assessment report prepared by the United Kingdom adsorption data for 13 soils are summarized that show KD values in the range of 0.8-21.3 ml/g with a geometric mean of 4.3 ml/g. The ketone metabolite showed on average a slightly higher affinity for adsorption to soil with KD values in the range of 2.1-13.5 with a mean of 8.0 across 6 soils.
Results from laboratory soil column leaching experiments summarized in U.S. EPA indicated low mobility in the experiments using methine-labeled Paclobutrazol(CAS NO:76738-62-0) in soils ranging in texture from sand to clay-loam. The experiments using triazole-labeled Paclobutrazol showed low mobility in columns of sand and sandy loam soils, and mobility in loamy sand and clay loam soils. In all cases, the majority (58.6-90.7%) of applied Paclobutrazol aged residue did not leach out of the upper 10 cm of the treated soil columns.
Although characterized as moderately mobile in laboratory studies, no significant movement of this chemical was detected in field studies in agricultural soils. In the orchard studies, Paclobutrazol residues (parent plus degradate) were detected at 10% or less of total applied in soils with depths of 48 inches in the California study, 24 inches in West Virginia study, and 48 inches in the Florida study.
These depths are the maximum depths sampled at each study. No information was provided on the nature or type of soils in the summary document. The Paclobutrazol ketone metabolite was predominately detected in the subsurface soil layers, also at insignificant levels.
A scientific publication by Baris et al. (2010) provided information regarding the potential of Paclobutrazol to impact groundwater from its use on turf areas. Paclobutrazol was included in a comprehensive evaluation of water quality monitoring data and assessment. This evaluation considered water quality data for a large number of turf-related pesticides from 44 studies involving 80 golf courses in the US over a 20-year period. PBZ was found in 3/440 groundwater samples, with the highest detection at 4.2 µg/L.
Want to learn more information about Paclobutrazol, you can access the guidechem.com. Guidechem.com is just a place for you to look for some chemicals.
2013年12月13日星期五
2013年11月24日星期日
Paclobutrazol used in farm
Paclobutrazol is a triazole type plant growth retardant which blocks gibberellin biosynthesis and are involved in reducing abscisic acid, ethylene and indole-3-acetic acid while increasing cytokinin levels. It promotes fruit set in the states of inhibited development . It is also known that it protect plants against abiotic stresses.
Uniconazol is another triazole type plant growth retardant. Though each plant hormone evokes many different specific biochemical, physiological, or morphological responses, the effects of different hormones overlap and may be stimulatory or inhibitory to regulate plant development and growth.
Paclobutrazol(CAS NO:76738-62-0), it can be classified as the growth retardants, which can be sub-classified as gibberellin biosynthesis inhibitors or compounds which are not involved in inhibiting gibberellin biosynthesis. abscisic acid, cimetacarb, daminozide, dikegulac, maleic hydrazide, mefluidide, and morphologically active substances (morphactins: chlorfluren, chlorflurenol, dichlorflurenol, flurenol).
For Trees and Shrubs
Paclobutrazol(CAS NO:76738-62-0) is used by arborists to reduce shoot growth and has been shown to have additional positive effects on trees and shrubs. It is used to improve their resistance to drought stress, darker green leaves, higher resistance against fungi and bacteria, and enhanced development of roots. Cambial growth, as well as shoot growth, has been shown to be reduced in some tree species.
Paclobutrazol is absorbed by roots and stems, and to a lesser extent, by leaves. Therefore, it can be applied as a spray, sprench, drench, or bulb or young-plant dip. Sprays are more effective when they penetrate plant canopies so that there is contact with stems. Plants absorb paclobutrazol with 30 minutes, and so crops can be watered relatively soon after PGR application without losing efficacy. Once absorbed, the products have a fairly long residual effect, so they are often used on aggressive bedding plants and herbaceous perennials, as well as potted flowering plants such as poinsettia. In addition, paclobutrazol is used as a spray on some vigorous plug and liner crops, especially during periods of warm weather.
For Aggressive Crops
Early paclobutrazol applications are desirable once roots have reached the pot edges, typically seven to 10 days after transplant. Growers are encouraged to perform their own trials to determine appropriate rates for their growing conditions and specific crops. The effects are strongly recommended.
A wide range of paclobutrazol concentrations are used on floriculture crops. Factors that influence appropriate rates include the crop, the magnitude of the response desired, crop maturity, volume of application and growing climate. A paclobutrazol spray at 5 to 10 ppm can be appropriate for bedding plants with moderate vigor, whereas at least twice that may be needed for aggressive crops, especially when grown during the late spring. On aggressive herbaceous perennials, typical spray rates are 60 to 90 ppm. None of the products can legally be applied to vegetable or herb crops.
Want to learn more information about Paclobutrazol, you can access the guidechem.com. Guidechem.com is just a place for you to look for some chemicals. Guidechem provide the most convenient conditions for the international buyers and let these leads benefit all the business people.
Uniconazol is another triazole type plant growth retardant. Though each plant hormone evokes many different specific biochemical, physiological, or morphological responses, the effects of different hormones overlap and may be stimulatory or inhibitory to regulate plant development and growth.
Paclobutrazol(CAS NO:76738-62-0), it can be classified as the growth retardants, which can be sub-classified as gibberellin biosynthesis inhibitors or compounds which are not involved in inhibiting gibberellin biosynthesis. abscisic acid, cimetacarb, daminozide, dikegulac, maleic hydrazide, mefluidide, and morphologically active substances (morphactins: chlorfluren, chlorflurenol, dichlorflurenol, flurenol).
For Trees and Shrubs
Paclobutrazol(CAS NO:76738-62-0) is used by arborists to reduce shoot growth and has been shown to have additional positive effects on trees and shrubs. It is used to improve their resistance to drought stress, darker green leaves, higher resistance against fungi and bacteria, and enhanced development of roots. Cambial growth, as well as shoot growth, has been shown to be reduced in some tree species.
Paclobutrazol is absorbed by roots and stems, and to a lesser extent, by leaves. Therefore, it can be applied as a spray, sprench, drench, or bulb or young-plant dip. Sprays are more effective when they penetrate plant canopies so that there is contact with stems. Plants absorb paclobutrazol with 30 minutes, and so crops can be watered relatively soon after PGR application without losing efficacy. Once absorbed, the products have a fairly long residual effect, so they are often used on aggressive bedding plants and herbaceous perennials, as well as potted flowering plants such as poinsettia. In addition, paclobutrazol is used as a spray on some vigorous plug and liner crops, especially during periods of warm weather.
For Aggressive Crops
Early paclobutrazol applications are desirable once roots have reached the pot edges, typically seven to 10 days after transplant. Growers are encouraged to perform their own trials to determine appropriate rates for their growing conditions and specific crops. The effects are strongly recommended.
A wide range of paclobutrazol concentrations are used on floriculture crops. Factors that influence appropriate rates include the crop, the magnitude of the response desired, crop maturity, volume of application and growing climate. A paclobutrazol spray at 5 to 10 ppm can be appropriate for bedding plants with moderate vigor, whereas at least twice that may be needed for aggressive crops, especially when grown during the late spring. On aggressive herbaceous perennials, typical spray rates are 60 to 90 ppm. None of the products can legally be applied to vegetable or herb crops.
Want to learn more information about Paclobutrazol, you can access the guidechem.com. Guidechem.com is just a place for you to look for some chemicals. Guidechem provide the most convenient conditions for the international buyers and let these leads benefit all the business people.
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