الفهرس 
Pesticide metabolism and formation of bound residuesOnly 14 pages are availabe for public view
 |  | from | 226 |  |  |
| | | from | 226 | | |
Abstract
The labeled 14C- pirimiphos-methyl was used to study the fate, metabolism and distribution of the pesticide in soil and plant. The non labeled was used to estimate the following biochemical parameters (soluble sugars, RNA, DNA and proteins) in both plant and worms, while estimating 14C-fixation (as indication for photosynthetic process), chlorophylls ”a”, ”b” and carotenoids in plant and determination of some enzymes activity in the earthworm (cholinesterase, ALT,AST and GST).
1. After applying 3 doses (R, 3R and 9R) of pirimiphos-methyl on soil the data revealed that the majority of the recovered radioactivity was confined in the upper soil layer (0-5 cm) for all doses. Water residues in upper soil showed a decline (14.0, 5.31 and 1.87 %) while, the methanol extractable residues showed (21.50, 17.80 and 25.25%) of the applied doses. The percentages of bound residues in the upper soil layer were (16.0, 16.0 and 17.50 %) of the applied dose. TLC analysis revealed that the majority of the recovered radioactivity in the soil was in the form of the parent compound.
2. In the lower layer of the soil (5-10 cm) no 14C-activity was detected in water residues, while methanol extractable residue showed decreased activity (9.30, 6.50 and 2.70 %), while the bound residue percents were (2.20, 0.27 and 0.13 %).
3. The TLC analysis revealed that the majority of the 14C-activity was in the form of parent compound.
4. In Phaseolus vulgaris plant the largest amount of 14C-pirimiphos-methyl was seen in the following descending order; leaves > stems > pods > roots. The pirimiphos-methyl was translocated from leaves to pods however a low percent of the applied dose could be recovered (1.07, 0.46 and 1.50 %) in the pods.
5. The TLC analysis of the shoot revealed that the parent compound contributed to (50.80, 46.60 and 46.20 %) of the applied dose. Furthermore, (0.58, 2.80 and 1.50%) was in the form of water soluble conjugate, while compound II (2-diethylamino-4-hydroxy-6-methyl pyrimidin) was recognized as a minor metabolite. In pods the amount of water soluble conjugate and the compound II (2-diethylamino-4-hydroxy-6-methyl pyrimidin) were low compared to the parent compound in the pods.
6. Compared to the control untreated plants, the 3 doses of pirimiphos-methyl in the plant significantly decreased 14C-fixation by the doses applied. On the other hand, chlorophylls ”a”, ”b”, carotenoids and the total pigments were not significantly changed.
7. The soluble sugars content and RNA increased due to all doses while the DNA content and the total proteins decreased due to all doses.