Plants organic translocation

A. Pich, G. Scholz, and U. W. Stephan, Iron-dependent changes of heavy metals, nicotianamine, and citrate in different plant organs and in the xylem exudate of two tomato genotypes. Nicotianamine as possible copper translocator. Plant Soil 765 189 (1994). 

Although the exact role of boron in plants is unknown, several physiological and biochemical activities associated with tissue boron content have been supported experimentally. This review covers some recent work on the role of boron in (1) organic translocation in plants, (2) enzymatic reactions, (3) plant growth regulator response, (4) cell division, (5) cell maturation, (6) nucleic acid metabolism, (7) phenolic acid biosynthesis, and (8) cell wall metabolism. 

Section VI indicates that availability of nitrate at the induction and assimilation sites plays a major role in regulating the level of nitrate reductase and the in situ rate of reduction of nitrate. If this is valid, then factors that regulate the uptake, translocation, and entry of nitrate into the cytoplasm of cells of various plant organs have more significant effects on regulating enzyme induction and rate of nitrate assimilation throughout the life cycle of plants than other mechanisms that affect induction, inhibition, and assimilation. 

Figure 4.4b. Radioactive ricinine infiltrated into Ricinus communis shoots distribution of the label versus time (Nowacki and Waller, 1975). Courtesy of the authors and the Society of Translocation and Accumulation of Nutrients in Plant Organisms, Warsaw.

Change of an alkaloid spectrum in a plant organ during its development often indicates at least one phenomenon de novo synthesis, translocation, and degradation (e.g., tabersonine and the pair dehydroaspidospermidine-vincadifformine on page 217). 

Plant uptake is one of several routes by which an organic contaminant can enter man s food chain. The amount of uptake depends on plant species, concentration, depth of placement, soil type, temperature, moisture, and many other parameters. Translocation of the absorbed material into various plant parts will determine the degree of man s exposure—i.e., whether the material moves to an edible portion of the plant. Past experience with nonpolar chlorinated pesticides suggested optimal uptake conditions are achieved when the chemical is placed in a soil with low adsorptive capacity e.g., a sand), evenly distributed throughout the soil profile, and with oil producing plants. Plant experiments were conducted with one set of parameters that would be optimal for uptake and translocation. The uptake of two dioxins and one phenol (2,4-dichlorophenol (DCP)) from one soil was measured in soybean and oats (7). The application rates were DCP = 0.07 ppm, DCDD 0.10 ppm, and TCDD = 0.06 ppm. The specific activity of the com-... 

E. Liljeroth, P. Kuiknian, and J. A. Van Veen, Carbon translocation to the rhizo-sphere of maize and wheat and influence on the turnover of native soil organic-matter at different soil nitrogen levels. Plant Soil 161 233 (1994). 

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. 

In the field of organic phosphorus compounds there is a wealth of highly toxic compounds from which to pick a potential insecticide. The ultimate choice will be based not only on toxicity to a certain group of insect species, but on volatility, stability, safety in handling and applying, and freedom from plant injury, spray-residue and translocation hazards, and long-term toxicity to man and animals. 

Lead may be taken up in edible plants from the soil via the root system, by direct foliar uptake and translocation within the plant, and by surface deposition of particulate matter. The amount of lead in soil that is bioavailable to a vegetable plant depends on factors such as cation exchange capacity, pH, amount of organic matter present, soil moisture content, and the type of amendments added to the soil. Back-... 

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