Vol. 15â1961 - NorthEastern Weed Science Society
Vol. 15â1961 - NorthEastern Weed Science Society Vol. 15â1961 - NorthEastern Weed Science Society
12. t endeucy for the radioactivit¥ to become smeared out over th p81Jer indicating the development of a number of radioactive comp~\lnds. The triazine herbicides have been ofilarticular inter st in the study of metabolism of herbicides by plants.. These recently devel ped materials (9) have shown some amazing differences in selectivity between ~ 'ants. The selectivity of simazlne and atrazine for corn despite their road activity against other grasses is especially striking. The tolerance of the corn plant for simazine andstrazine C&l be accounted for on one of thr e basis: the compound is not taken up by tbe corn plant, (b) the enzyme s stems of the pl ant; are unaffected by the presence of .the chemical.'9r (c) the p ant is able to metabolize the compound to, innocuous products. Shortly aftethe selectivity of simazine and atraziy,toward cor,n was demonstrated, we u ertook to study this phenomena using C ..labeled compounds. . The very early experiments clearly indicated, resence of C14 in the sample, that the plant was capable of t"'ingup readlly etectable amounts of simazine and atrazine. ,Of course it w0\11dbe argued that th C l4 ..1abeled material absorbed by the plant was not simazlne or atrazine ut something to which they had been converted by so11 microorganisms. BoWENr, chromatography of soU extracts demonstrated the presence of large quani!t1 8 of the parent triazine herbicide. qlearly then, at least one of the C ..c ntaining compounds taken up by the corn, was the parent triazine. The question then ar~se as to whether the C 14 found i the plant represented the parent herbicide or whethe~ this herbicide had b n altered by the plants metabolism. Since it Was known that simazineandatr ine could be quantitatively extracted from plant tissue with chloroform amples of the ~lant tissue were taken at time intervals and exhaustively tracted with chloroform. The following table presents the results of th s study. The Percentage Table 5 of Total C14 in Treated Corn which was ChI roform Extractable Simazin Rate Days follOWing % C14 chloroform lb/A treatment extractable 2 49 41.0 21 83 8 --. , .. 42.4 89 2 91 33.8 56 15.4 8 39.8 71.2 2 119 18.1 113 72.3 8 28.7 54.9 2 119, ears 53.8 113, ear 48.6 8 '39.4 59.6 The fact that there was a change in tbe percentage of . he total radioactivity in the plant extractable with chloroform gave evidence that these compounds were being altered by the plantts metabolism. Clearly it would ot be unreasonable to
13. Atrazine Days following cpm/O. ml % Solution rate/A treatment Before After Retained Atrazine 374 3.3 99. I Plant extract 2 119 221. 7 6.3 72.2 Plant extract 8 119 207.1 28.1 86.5 Extract of ear 8 119 61. 8 32.0 40.2 If the triazine is being degraded by the plant I s metaboli c activities. the question arises as to how far this degradation is carried. 11· the degradation is complete. then it would be expected that for radioactivity car~on dioxide should be evolved from the plant. In order to test whether or not this Was the case. the closed chamber metabolism experiment as described ~revious y·was attempted. In this case. corn plants were germinated in sand and then t aken as the test plant. Table 7 clearly demonstrates that the plant is capable of comp ete degradation of simazine and atrazine. Table 7 Metabolism of e l4 Simazin and Atrazine bIeorn Plants as Measured by the Release of e 40 2 IJ.gTriazine %Triazine Duration IJ.gTriazine remaining metabolized Experiment hours metabolized in Dlant of that taken UP Simazine I 50 .46 2 48 .19 2.0 8.7 3 (in dark) 68 .91 • S3 63.2 Atrazine I 54 .67 3.05 18.0 2 72 .30 1.49 16.8 3 (in dark) 70 .28 .73 27.7 Since the corn plant is clearly capable of complete oxidation of the triazines as shown above. it now becomes of interest to determine ty what mechanism this is accomplished. This was investigated using expressed scI' of corn plants to ascertain whether or not the reaction was the result of met~bolic aetiviti~8.
- Page 1 and 2: THE USE OF VEGETATIVECHARACTERISTIC
- Page 3 and 4: In a few grasses with smooth sheath
- Page 5 and 6: 5. FACTORSINFLUEUCINGTHE PERFORFANC
- Page 7 and 8: 7. The introduction of synthetic or
- Page 9 and 10: The com;onents the distribution of
- Page 11: grains. We early found that the oat
- Page 15 and 16: 15. not find an abundant production
- Page 17 and 18: Weed Control In Suburbia 1 Howard H
- Page 19 and 20: For establishing new lawns, I would
- Page 21 and 22: Any improvement that you can make i
- Page 23 and 24: PROMISINGNEWCHEMICALSFORWEEDCONTROL
- Page 25 and 26: 25. Promis ins results have also be
- Page 27 and 28: 27. (Lycbnis alba), cinquefoil (Pot
- Page 29 and 30: THE EFFECTS OF ADDED PENETRANT AIDS
- Page 31 and 32: ... Surfactant Produced bz: . 31
- Page 33 and 34: 33. 33. of scintillation solution,
- Page 35 and 36: Table 3. The Net Counts Per Minute
- Page 37 and 38: The comparisons for lower leaves, s
- Page 39 and 40: 39. SUMMARY Tests using 2-C 14-1abe
- Page 41 and 42: 41. RECENTDEVELOPMENTS IN THEUSE OF
- Page 43 and 44: second application be made not late
- Page 45 and 46: 45. Combinations of vegadex-Randox
- Page 47 and 48: 11/ Persistence of Soil-Incorporate
- Page 49 and 50: Plot size varied from 9 sq. ft. to
- Page 51 and 52: Lower rates of R-1856 were tested o
- Page 53 and 54: greenhouse tests are listed below.
- Page 55 and 56: PROGRESSREPORTON LAY-BYUEEDCONTROLI
- Page 57 and 58: 57. Table 1. Effect of sodium silic
- Page 59 and 60: Sheets (1959) studied, under labora
- Page 61 and 62: M, ',. • • •• • " ' Treat
13.<br />
Atrazine Days following cpm/O. ml %<br />
Solution rate/A treatment Before After Retained<br />
Atrazine 374 3.3 99. I<br />
Plant extract 2 119 221. 7 6.3 72.2<br />
Plant extract 8 119 207.1 28.1 86.5<br />
Extract of ear 8 119 61. 8 32.0 40.2<br />
If the triazine is being degraded by the plant I s metaboli c activities. the<br />
question arises as to how far this degradation is carried. 11· the degradation is<br />
complete. then it would be expected that for radioactivity car~on dioxide should<br />
be evolved from the plant. In order to test whether or not this Was the case.<br />
the closed chamber metabolism experiment as described ~revious y·was attempted.<br />
In this case. corn plants were germinated in sand and then t aken as the test plant.<br />
Table 7 clearly demonstrates that the plant is capable of comp ete degradation of<br />
simazine and atrazine.<br />
Table 7<br />
Metabolism of e l4 Simazin and Atrazine bIeorn Plants as Measured<br />
by the Release of e 40 2<br />
IJ.gTriazine %Triazine<br />
Duration IJ.gTriazine remaining metabolized<br />
Experiment hours metabolized in Dlant of that taken UP<br />
Simazine I 50 .46<br />
2 48 .19 2.0 8.7<br />
3 (in dark) 68 .91 • S3 63.2<br />
Atrazine I 54 .67 3.05 18.0<br />
2 72 .30 1.49 16.8<br />
3 (in dark) 70 .28 .73 27.7<br />
Since the corn plant is clearly capable of complete oxidation of the triazines<br />
as shown above. it now becomes of interest to determine ty what mechanism<br />
this is accomplished. This was investigated using expressed scI' of corn plants<br />
to ascertain whether or not the reaction was the result of met~bolic aetiviti~8.
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