Robert M. Devlin

Initial and residual activity of glyphosate and SC-0224 in a sandy soil

Abstract Initial and residual herbicide activity of glyphosate and SC-0224 (trimethylsulphonium carboxymethylaminomethylphosphonate) when applied to a sandy soil was investigated. A bioassay employing wheat ( Triticum vulgare L., cv. Mericopa) was used to determine the residual activity of the herbicides on different characteristics of plant growth. At 5 kg/ha both herbicides significantly reduced shoot length. This was observed in wheat planted immediately as well as 10 days after application. SC-0224 was more active than glyphosate, significantly reducing shoot length at the 2·5 kg/ha rate 10 days after application. Root length was reduced by both herbicides at 2·5 and 5 kg/ha in wheat planted 10 days after application. Reductions in fresh and dry weight were also observed for both shoots and roots. It is apparent that SC-0224 and glyphosate have residual herbicide activity in sandy soil, at least up to 10 days after application, and that SC-0224 has more herbicidal activity than glyphosate in this respect.

Response of Potamogeton pectinatus L. to norflurazon

The herbicidal activity of norflurazon on Potamogeton pectinatus L. grown in the laboratory under high and low light intensities was studied. P. pectinatus grown under a light intensity of 10, 760 lux responded to norflurazon with a significant reduction in chlorophyll content. Under a low light intensity of 108 lux this influence was severely curtailed. Norflurazon blocks carotenoid synthesis and in the absence of carotenoids chlorophyll is subject to photodynamic destruction. Under low light intensity photodynamic action is limited even in the absence of carotenoids.

Influence of BAS-145138 on the Activity of Sulfonylurea and Imidazolinone Herbicides

Abstract This study demonstrates that corn can be partially safened by BAS-145138 against sulfonylurea and imidazolinone herbicides. The corn seeds were impregnated with BAS-145138 by soaking the seeds for 6 h in solutions of the safener. BAS-145138 had no effect on corn growth. However, corn shoot and root growth in length, fresh weight, and dry weight was partially protected by BAS-145138 from the phytotoxic effects of the sulfonylurea herbicides thiameturon and CGA -136872. Similar protection was given to corn against the phytotoxic activity of the imidazolinone herbicides imazapyr, imazaquin, and imazethapyr. This study suggests that corn could be safened with BAS-145138 against the phytotoxic effects of residual amounts of sulfonylurea and imidazolinone herbicides found in rotations take place.

The influence of benzo(a)pyrene on the growth of wheat and corn

Abstract Corn seeds responded to soaking in aqueous solutions of benzo(a)pyrene with increased root growth. Growth stimulation decreased from 14% to 0 with increasing concentrations (0.0005–0.02 ppm), and with increasing soaking times (6 and 12 hr). Shoot growth and dry weights of shoots were not affected. Wheat did not respond as distinctly as corn to similar treatments. A decrease in the growth of shoots and roots with increasing BaP concentrations was not statistically significant.

Effect of 2-chloroethylphosphonic acid on enzyme induction in barley endosperm

The effect of 2-chloroethylphosphonic acid (CEPA) on GA induction of α-amylase in the barley endosperm test was studied. No amylolytic activity could be detected when CEPA was substituted for GA. When CEPA was added simultaneously with GA it inhibited GA induction of α-amylase. Inhibition increased as increasing concentrations of CEPA were added. This inhibition is partially due to a direct influence of CEPA on the enzyme-starch reaction.