THE ROLE OF SYSTEMIC AND NON SYSTEMIC FUNGICIDES ON THE PHYSIOLOGICAL AND BIOCHEMICAL PARAMETERS IN GOSSYPI UM HIRSU T UM PLANT, IMPLICATIONS FOR DEFENSE RESPONSES

摘要

Fungicides using for an effective control of plant diseases have become crucial in the last dec- ades in the agricultural system. The efficiency of seed dressing fungicides in controlling damping off caused by Rhizoctonia so/am’ under greenhouse con- ditions and its effect on plant growth and metabolism of cotton plant seeds was studied by treatment with systemic and contact fungicides. The results showed that Monceren showed the highest efficiency (72) while each of Montoro and Sumi-8 showed the low- est efficiency (48 and 36 respectively) in con- trolling damping off. Significant decrease in plant height, dry weight of plant, phytohormones, photo- synthetic pigments, soluble sugars, soluble proteins, total free amino acids, polyphenol oxidase caused by Bastin fungicide, but caused significant increases in total phenols, flavonoids, antioxidant enzymes, re- duced glutathione, lipid peroxidation and hydrogen peroxide as compared with untreated plants. On the other hand, Topsim and Monceren fungicides in- creased all the above recorded parameters except phenols, MDA and H202 as compared with untreated plants. Our results indicated that Topsim Monceren and Premis fungicides can be used as growth regula- tors and decreased plant diseases.