No abstract

A clean-up procedure for soil and plant samples utilizing a non-ionic exchange resin column followed by treatment with lead acetate was developed for determining microgram quantities of hexaflurate (potassium hexafluoroarsenate) spectrophotometrically. The method is sensitive to 0.45 ppm with a standard deviation of 0.09 ppm with a recovery of better than 85%. Samples high in organic matter require this treatment to remove interfering substances. Soil samples containing little or no organic matter could be analyzed by using either the lead acetate treatment or the non-ionic exchange resin column. Soil and plant samples analyzed 5 to 7 yr following treatment of south Texas soils for pricklypear (Opuntia spp.) control were found to contain trace quantities of hexaflurate. Downward movement of hexaflurate is either very slow or plants continually assimilate the ion and redeposit it on the soil surface through decomposition of plant parts. The tri- and pent-oxide forms of arsenic did not interfere with analysis of the hexaflurate ion using the clean-up procedure.

No abstract

CBC (2,5-dichlorobenzoyl chloride) and MCB (methyl-2,5-dichlorobenzoate) function as plant growth regulators in a gaseous phase or in an aqueous solution. Sorghum [Sorghum bicolor (L.) Moench. ‘Martin’] and soybean [Glycine bicolor (L.) Merr. ‘Lee’] seeds were temporarily inhibited or delayed from germinating, but overcame the inhibition in time so there was no significant reduction in total germination. Seedlings produced from sorghum and soybean seed germinated and grown in aqueous solution of 35 μg/ml CBC or MCB were shorter and weighed less than control seedlings. Soybean seed treated with the vapors of CBC and MCB produced seedlings significantly reduced in dry weight as compared with that of controls. Foliar application of 500 or 1000 μg/ml of CBC significantly reduced the growth of soybean but not sorghum seedlings. Soybean seedlings treated with the vapors or an aqueous solution produced leaflets more narrow and thicker than control seedlings. A lethal response attributable to CBC or MCB was not recorded.