We thought that the differences noted in the cloudo-grams and cloud points of the materials containing the same average moles of ethylene oxide might lie in the distribution of moles around the average. Therefore, samples were made by combining samples of different average moles to contain an average of 11.5 ~0.2 moles of ethylene oxide and were processed through this procedure. Figure 5 is a graphic representation of the distribution of the moles of ethylene oxide of these combinations based on the Poisson Distribution of each component. Figure 6 illustrates the cloud-o-grams and cloud points obtained from these combinations.As illustrated, we have a preponderance of low molecular weight material (8 moles) but enough of the higher weights to average out at the desired level.However, the cloud points obtained are not what one expects of 11.5 mole material, but more like that of a 9 or 10 mole material. Although the average moles are nearly equal, the cloud-o-grams reflect the differences in the distribution around the average.Additional confirmation of the effect of the mole distribution around the average was obtained by plotting the data of Mayhew and Hyatt (3) on arithmetical probability paper. AbstractFreezing points of mixtures of palmitie and linoleic, or palmitie and linolenic acids, the predominant fatty acids in plants~ decrease slowly as the unsaturated fatty acid is increased to 60 mole %. Beyond this per cent the freezing point is depressed quite markedly by each addition of unsaturated fatty acid. Linoieie and linolenic acids have similar effects on the freezing points of the mixtures until about 82 mole % unsaturated fatty acid. Differences of less than 5% in the amount of unsaturated fatty acid have a marked effect on the freezing point of mixtures at the approximate composition of fatty acid in plant membrane lipids.

High specific radioactivity (26.3 mc/mmole) racemic 2-14C-abscisic acid was synthesized. An aliquot of abscisic acid, 1.2 X 10'-M in aqueous methanolic solution, was applied to the surface of either a cotyledon or the first true leaf of 8-to 32-dayold cotton seedlings (Gossypium hirsutum L.). After various intervals (6-192 hours), the seedlings were processed for autoradiography, counting, and identification of the radioactivity. After 6 hours, radioactivity was observed moving basipetally out of the treated leaf toward the roots. Four days later, radioactivity could be detected throughout the whole seedling. After 8 days, 10% of the recovered radioactivity was found in the roots, and 80% remained in the treated leaf blade. Neither leaf type nor age had any effect on the abscisic acid movement or pattern of distribution. Isolated radioactivity from the roots was identified as abscisic acid, based on comparison with an authentic standard by thin layer chromatography, gas-liquid chromatography, or gas-liquid chromatography-mass spectrometry.Abscisic acid has been isolated from cotton plants and identified (6, 24, 25). It has also been found in a large number of plant species (3, 11,18,22,23 MATERIALS AND METHODS Synthesis of High Specific Radioactivity 2-14C-Abscisic Acid. Although a synthesis of 1-"4C-methyl (triphenylphosphoranylidene) acetate has been published (5), the description given is incomplete, and the yield of the 1-4C-compound reported is lower than the yields in the macrosynthesis (17). A similar Wittig reagent was prepared with good yield as follows. Ethyl-2-"C-bromoacetate (21.0 mg) 28.7 mc/mmole, (ICN-Tracerlab) in 0.25 ml of benzene was transferred to a 15-ml graduated centrifuge tube, and the shipping vial was rinsed five times with 0.45 ml of benzene. Triphenylphosphine (132 mg, 0.503 mmole) was added, dissolved in the benzene, and the tube was covered with aluminum foil and allowed to stand at room temperature for 24 hr. The tube was then spun for 15 min at 3000 rpm, and the benzene was decanted. Fresh benzene (2.5 ml) was added, the tube was shaken and then centrifuged again for 15 min at 3000 rpm, and the benzene rinse was decanted. The tube was then dried 2 hr in a vacuum oven at about 250 mm Hg and 40 C to yield 50.22 mg of salt (93.0% of theory). Previous trial runs had given quantitative yields. The salt was dissolved in 2.5 ml of distilled water, and a drop each of 0.1% phenolphthalein alcohol solution and 1% Tween 20 solution was added followed by 4 drops of 10% KOH to a pink end point. The precipitated ethyl (triphenylphosphoranylidene)-2-'4C-acetate was spun down for 15 min at 3000 rpm, the supernatant was decanted, the precipitate was rinsed with 2.5 ml of water and recentrifuged, and the water was decanted. The product was then dried overnight at 250 mm Hg and 60 C to yield 35.67 mg, 87.5% of theory for this step and 81.4% over-all. Trial runs had given 84 + 2% of theory in this step.Next, 4-(2, 6, 6-trimethyl-1 -hydroxy-4-keto-2-cyclohexen-1-yl)-3-buten-2-one, 0.1024 mmole...

A Bioactive Analog of Abscisic AcidCis,trans-a-ionylideneacetic acid [cis,trans-j-(2,6,6,-pentadienoic acid] is a potent plant bioactive substance approaching abscisic acid (ABA) in activity.This acid was prepared via a Reformatsky reaction of a-ionone (I) with ethyl bromoacetate (11). The initial condensation product was the P-hydroxy ester (111) and this was dehydrated to give two isomeric a-ionylideneacetates (Va, VI,) and a third isomer (IVa). The isomers were separated by vacuum distillation and after alkaline hydrolysis, the cis,trans and trans,trans-a-ionylideneacetic acids (vb, VIb) were crystallized. The bioactivity of cis,transa-ionylideneacetic acid (vb) relative to abscisic acid was determined by the inhibition of 3-indoleacetic acid (IAA) induced Avena straight growth and by the acceleration of abscission in cotton explants. study of a chemical structure-biological activity relationship was undertaken as a n approach toward

Shell Chemical Co. for providing the two insecticides used in this study. Mention of proprietary products is for identification only and does not necessarily imply endorsement of these products bs the V. S. Department of Agriculture.

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