Vol. 15—1961 - NorthEastern Weed Science Society
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Vol. 15—1961 - NorthEastern Weed Science Society

Vol. 15—1961 - NorthEastern Weed Science Society Vol. 15—1961 - NorthEastern Weed Science Society

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08.06.2015 Views

Qolumn Separation: Cellulose. A 24 x 1 7/8 inch column 1 packed with Whatmanstandard grade cellulose powder was used as a second system. The column was packed wet, the sample placed on top of the packed powder and 80% Ethanol was passed through the column. The fractions were collected with a G.M.E •. fraction collector using a Packard model 235 U.V. monitor to detect the cuts. Column ~eparatiQll: Silicic acid. The most recent attempt at purification has been with Mallinckrodt Silicic acid. The silicic acid was deactivated as described by Jarboe (2) in 1960. Twelve grams were sulurried in chloroform and added to a jacketed 15 rom x 450 rom column and the HCC1 3 was drained to the . top of the column. The residue from the active sections of 8 chromatogram papers was adsorbed to a glass wool plug wetted with distilled water. A second plug was used to adsorb remaining residue. A gradient system of chloroform and methyl alcohol was used to elute the column. 500 ml methanol containing .5 ml conc NH 40H was dripped into 300 ml HCC1 3 in· B:elosed mixing chamber, thus the elulion began with 100% HCC1 3 and became logarithmetically diluted with the ammoniated methyl alcohol. The fractions were again collected with the G~M.C. fraction collector. Adsorption Qn Activated Carbon. The extract from one gram of quackgrass was mixed with 5 grams Acetic acid-washed Norite, and filtered with a Buchner funnel. The filtrate was eluted with methanol and with methanol containing ammonia and the three fractions were tested for activity. Results & Discussion The inhibition from four grams of quackgrass was completely eluted with 30 ml of water (Table I). A brownish yellow color was associated with the inhibiting fractions. Table I. Water extraction of the inhibitor from ground rhizomes in a column. MI. water 5 10 15 20 2$ 3Q 8Q MMgrowth of seedlings 00 00 00 9 24 50 ~ ~ 49 %Inhibition 100 100 100 83 53 3 14 15 5 An increase in growth in the 40 ml fraction indicates the possibility of stimulation from very small quantities of the inhibitor. Data from other experiments, particularly on column work have indicated stimulation. Helgeson (3) reported such effects~ More data with pure compounds will be needed to establish this point. . Ethyl alcohol extractions were less efficient than water extractions in removing the inhibitor(s).

331. Two solvent systems (No. 1 and No•. 2) were found to give satisfactory results when run in either an ammonia or acetic acid atmosphere. The ammonia atmosphere was preferred because the solutions extracted were neutral and did not require pH alteration for the assay. Migration values in the butanone, T-butanol, Water System (~2) -- A complete analysis of a chromatogram showed several inhibitory regions. One of these (Area A in figure 1) was present only in certain harvests of quackgrass. Fertility and organic content of the soil may be factors in the occurr'nce of this inhibitor. An assay of origional extract showed nearly complete inhibition whereas extracts of quackgrass from earlier harvests inhibited in the 50% range with little inhibition in the A section. The inhibititor reported in our early experiments is extracted from areas corresponding. to E and F in figure 1. In some instances almost total inhibition was found in the upper area with less inhibition in the E-F area. The upper inhibition was not adsorbed by Norite using batch or column processes though this treatment took out all the color. It was at first thought this inhibition was due to mineral salts since they should have low migration values in the solvent systems used in this study. The nature of the inhibition from this area has not been explored since it was only recently observed. The assay of quackgrass taken from New York, Vermont, West Virginia, and Pennsylvania, and grown at state College showed a large variation in inhibition in preliminary trials. Further study will be made of this variation and inhibition tests will be made with quackgrass of a single clone grown at various levels of fertility. _. When the active material from the 2-butanone-T-butanol­ Water system was rechromatographed on a cellulose column using 80% Ethanol as the solvent impure crystals were observed in an active fraction. Further purification will be necessary before chemical characterization is attempted. .Recently silica gel columns have given very encouraging results but more work will have to be done to evaluate this procedure.

331.<br />

Two solvent systems (No. 1 and No•. 2) were found to give<br />

satisfactory results when run in either an ammonia or acetic<br />

acid atmosphere. The ammonia atmosphere was preferred because<br />

the solutions extracted were neutral and did not require pH<br />

alteration for the assay.<br />

Migration values in the butanone, T-butanol, Water System (~2)<br />

--<br />

A complete analysis of a chromatogram showed several<br />

inhibitory regions. One of these (Area A in figure 1) was<br />

present only in certain harvests of quackgrass. Fertility and<br />

organic content of the soil may be factors in the occurr'nce<br />

of this inhibitor. An assay of origional extract showed nearly<br />

complete inhibition whereas extracts of quackgrass from earlier<br />

harvests inhibited in the 50% range with little inhibition in<br />

the A section. The inhibititor reported in our early experiments<br />

is extracted from areas corresponding. to E and F in figure 1.<br />

In some instances almost total inhibition was found in the upper<br />

area with less inhibition in the E-F area.<br />

The upper inhibition was not adsorbed by Norite using<br />

batch or column processes though this treatment took out all<br />

the color. It was at first thought this inhibition was due to<br />

mineral salts since they should have low migration values in<br />

the solvent systems used in this study.<br />

The nature of the inhibition from this area has not been<br />

explored since it was only recently observed.<br />

The assay of quackgrass taken from New York, Vermont,<br />

West Virginia, and Pennsylvania, and grown at state College<br />

showed a large variation in inhibition in preliminary trials.<br />

Further study will be made of this variation and inhibition<br />

tests will be made with quackgrass of a single clone grown<br />

at various levels of fertility.<br />

_.<br />

When the active material from the 2-butanone-T-butanol­<br />

Water system was rechromatographed on a cellulose column using<br />

80% Ethanol as the solvent impure crystals were observed in an<br />

active fraction. Further purification will be necessary before<br />

chemical characterization is attempted. .Recently silica gel<br />

columns have given very encouraging results but more work will<br />

have to be done to evaluate this procedure.

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