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991.
The chlorophyll production of wheat (Triticum vulgare L. cv. Mericopa), corn (Zea mays L. cv. Everta), and alfalfa (Medicago sativa L. cv. Saranac), treated with the herbicide 4-chloro-5-methylamino-2-(3-trifluoro-methylphenyl)pyridazin- 3-one (norflurazon) and grown under high light intensity (10 760 lux) was markedly reduced. Corn and wheat seedlings germinated and grown for 7 days in an agar medium containing 1 mg/1 norflurazon were almost completely bleached. Alfalfa was even more sensitive to norflurazon, 0.1 mg/1 causing almost complete chlorosis. Under low light intensity (10.76 lux) the influence of norflurazon on chlorophyll production was greatly reduced. It is thought that norflurazon inhibits carotenoid synthesis leaving the chlorophyll of the plant subject to photooxidation. Electron micrographs of chloroplasts from green, partially bleached, and bleached areas of corn leaves treated with norflurazon indicate that the herbicide causes progressive deterioration of the lamellar system. 相似文献
992.
993.
The persistence of propyzamide in soil was studied by analysing soil samples taken at intervals two or three times after application in the spring to experimental fields. Single samples were taken from other fields. 8 to 12 months after autumn application. The concentrations were measured by electron-capture gas chromatography. Persistence is expressed in first-order dissipation rate constants and half-life values. Data were measured and collected on the adsorption of propyzamide on soils, the soil characteristics and the weather conditions. Computations of the mobility of propyzamide in soil were carried out for simplified systems. Results of measurements and computations are compared. 相似文献
994.
The influence of pre-treatment and post-treatment illumination upon the herbicidal effect produced in Phaseolus vulgaris L. cv. Berna by simeton, diuron, diquat and ioxynil was examined. The increased effect noted at lower pre-treatment and higher post-treatment levels of illumination was correlated with increased inhibition of net photosynthesis. This increased effect was ascribed to enhanced photo-oxidation. 相似文献
995.
D. J. Mowat 《Grass and Forage Science》1974,29(4):285-285
Elimination of shooly larvae increased grass yields daring the September feeding period. Increases were usually less than 10% bat in one case, where growth was abnormally slow, die increase was over 30% and in another, where the larval population was atypically dense, it was almost 60%. The effects of damage were not cumulative daring the feeding period; and at the end of this period insecticidreated plots sometimes gave lower yields than untreated plots. Fertilizer increases had a much greater effect on yield than did control of larvae and, where N was applied at 75 kg/ha (67 lb/ac) in spring, the additional effect of larval control was usually negligible. It is suggested that shoot-fly damage may be more serious in other localities. When turf containing shoot-fly larvae was ploughed, Oscinella spp. re-established themselves more successfully than others in seedling ryegrass bat did not damage the new sward appreciably. 相似文献
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