Plants organic phosphates

J. Gerke, Orthophosphate and organic phosphate in the soil solution of four sandy soils—evidence for humic-Fe(Al) phosphate complexes. Commim. Soil Sci. Plant Anal. 25 601 (1992). 

N. G. Juma and M. A. Tabatabai, Hydrolysis of organic phosphates by corn and soybean roots. Plant Soil 707 31 (1988). 

Because the phosphates are readily absorbed through the skin and are hazardous from exposure by any route, prevention of poisoning includes avoiding contact with the bare skin and avoidance of inhalation of the chemicals. It is recommended also that workers change their clothes completely and bathe with soap and water after every use of this material. Particular caution is indicated on the part of pilots engaged in airplane spraying because of the effects of the organic phosphates on the eyes. Parathion presents special problems because of its translocation into the plant. 

Gerke J. Humic (organic matter)-Al(Fe)-phosphate complexes an underestimated phosphate form in soils and source of plant-available phosphate. Soil Sci. 2010 175 417 25. 

As pointed out earlier, all U.S. cotton in commercial production is now harvested by machines. The application of harvest-aid chemicals to cause the plants to shed their leaves (defoliation) or to kill and dry the plant (desiccation) are common practices in many areas. Chlorates and organic phosphates are popular defoliant materials and arsenic acid is commonly used as a desiccant. 

APase in onion roots. Enzyme activity was mainly extracellular with the heaviest concentration in corner spaces between the epidermal and hypo-dermal layers. He suggested the possibility of a subcutaneous pore through which the enzyme could be released to the root surface. Bieleski and co-workers (Reid Bieleski, 1970 Bieleski Johnson, 1972) studied the psi induction and location of APase in duckweed (Spirodela oligorrhiza). APase in control plants was located primarily in and around the vascular strands. In P-deficient plants psi-APase activity was 10-20 times the control value. Enzyme activity was primarily located in the epidermis of the root and undersurface of the frond, the tissue locations most likely to provide access to phosphate esters in the medium. These workers further demonstrated that hydrolysis of organic phosphates occurred in the external medium and/or the apoplast followed by Pi uptake into the cell. 

The variability of the P content of fulvic acids appears to be a function of both the hydrologic conditions and the nutrient status of the aquatic system in which the fulvic acids were formed. McKnight et al. (1985) hypothesized that the P in Thoreau s Bog fulvic acids was in the form of organic phosphate esters or inositol phosphates, which are major phosphorus products from the breakdown of plant material. The solubility of these P-containing moieties would be greater in bogwater than in most surface... 

The Chi in the hairy roots and parent plant organs was extracted with a mixture of 80% acetone and 20% phosphate buffer (2.5 mol m 3,pH 7.8), and analyzed according to the method described by Porra et al. [17]. The activities of SOD and POD in the hairy roots and parent plant organs were spectrophoto-metrically determined using ferricytochrome C [18] and o-aminophenol [19], respectively. Fructose in the medium was analyzed by the Somogyi-Nelson method [20] or was determined using an HPLC with a refractive index detector. Light intensity was measured with a thermopile on the outer walls of flasks at the level of the medium surface or at the top of the Petri dish, and expressed as the mean of values determined at several positions. 

With emphasis on the need for pesticides in agriculture a BHC plant was commissioned in the private sector in 1952. A DDT plant in the public sector was established near Delhi in 1955. Production, which was only 462 tons in 1954-1955, increased to about 28,000 tons in 1968-1969. Other related pesticide products the country produces are organic phosphates, parathion, AlgP, methyl bromide, and ethylene dibromide, along with about 20 other compounds. 

Considerable attention has been devoted in recent years to discharges of spent phosphatic solutions [detergents] with respect to their enhancement of growth of aquatic plants, particularly certain algae. This subcycle is shown by dashed lines in Fig. 3.1.1 inasmuch as it is not natural, and it is necessarily incomplete because it is not known to what extent these organic phosphates are ultimately disintegrated and to what extent they are incorporated in lacustrine sediments. 

Fig.2.10 Phosphoglycerate utilization, (a) During the day. Photosynthesis in the chloroplast makes starch until there is no more room. The Calvin cycle continues to make triose phosphate, which exits the chloroplast in exchange for organic phosphate (Pi) entering the chloroplast and converting ADP to ATP. In the cytosol, the triose phosphate is mostly converted to sucrose but also to small amounts of other compounds such as amino acids for transport throughout the plant, (b) During the night. Phosphorylase is activated and it breaks up the starch to glucose 6-phosphate from which triose phosphate is made. The triose phosphate is exchanged for Pi. The Pi is a substrate for phosphorylase and keeps it active. Once in the cytosol, the triose phosphate is transferred mostly to mitochondria for respiration...

In addition to inorganic orthophosphates, phosphorus is bound in organic phosphates (ester linkages) within humus, from which plant available phosphate is set free by microorganisms (mineralization). Examples are nucleic acids, inisitol hexaphosphates as the largest group, and phospholipids. In agricultural soils, the C P ratio is in the order of 50 1. 

Plant species differ widely in the extent of phosphorus absorption by their roots. Forest trees take up P from insoluble compounds with the help of mycorrhizas, whereas phosphorus is removed from soils by harvested crops ( 6 kg ha in agriculture), erosion and to a small extent by leaching (-0.1 kg ha ) and volatilization as phosphine PH3. In the case of erosion, colloids with their surface-bound P are transported into surface waters, and this leads to the eutrophication of aquatic ecosystems, for example in lakes. Leaching losses occur only in sand and peat soils, and in the case of organic phosphates. Under extreme redox situations - as in some paddy soils - phosphate is reduced to PH3 as a gaseous product. 

Ca " binding to pectins and all other Ca-dependent processes. Additionally, A1 phosphates can be precipitated in the vascular system, and this inhibits vater and substance transports betv een plant organs the result is seen as plant vilting. 

Phosphorus is necessary for all organisms as a constituent of nucleic acids, phospholipids and other organic phosphate compounds. Its frequent deficiency in soils must be supplemented with phosphate fertilizers. Phosphorus is liberated from organic matter during ammonification. Phosphate is also made available to plants as a result of the formation by microorganisms of organic acids which dissolve insoluble inorganic phosphate compounds in the soil. 

Organic phosphorus compounds, primarily inositolhexaphosphates (probably more than 50% of all organic phosphates), occiu in soils. The parent cyclic polyol, inositol, exists in numerous stereoisomeric configurations, of which myo-, scyllo-, neo-, and cZZ-inositol have been isolated from soils as phosphate esters. The hexaphosphate of myoinositol (myo-IHP), phytic acid, occurs in plant tissues. It often occurs as phytin, the calcium magnesium salt. Esters of myo-IHP are readily adsorbed in acidic soil solution by clay minerals and finely divided hydrated oxides of iron and aluminum. Organic sulfur compounds present in soils probably occur primarily as amino acids—e.g., cysteine, cystine, and methionine. 

McKercher, R.B. and Anderson, G. (1989) Organic phosphate sorption by neutral and basic soils. Communications in Soil Science and Plant Analysis20, 723-732. 

Wild, A. and Oke, O.L. (1966) Organic phosphate compounds in calcium chloride extracts of soils identification and availability to plants. Journal of Soil Science 1 7, 356-371. 

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