title: Plant growth regulators induced urease activity in Cucurbita pepo L. cotyledons.
abstract: This study is aimed to investigate the activity of urease (EC 3.5.1.5, urea amidohydrolase) that catalyzes the hydrolysis of urea in 5-day-old Cucurbita pepo cotyledons subjected to various concentrations of different growth regulators. The treatment of C. pepo cotyledons with different concentrations (100-600 μmol) of different auxins [indole-3-acetic acid (IAA), indole butyric acid (IBA), indole propionic acid (IPA) and naphthalene acetic acid (NAA)]; or with different concentrations (100-300 μmol) of different cytokinins [kinetin, zeatin and benzyladenine (6-BA)] resulted in a significant increase of urease activity, compared to control. The optimal effects were recorded for each of 500 μmol of IAA and 300 μmol of zeatin treatments. A gradual increase in urease activity was detected in cotyledons treated with various concentrations (0.2-1.0 mM) of 28-homobrassinolide (HBL), in relative to control. A substantial increase in urease activity was observed in cotyledons subjected to different concentrations of triazole (10-60 mg L(-1)), containing either triadimefon (TDM) or hexaconazole (HEX), compared to control. The combination of 300 μmol zeatin with any of protein inhibitors, namely 5-fluorouridine (FUrd), cordycepin and α-amanitin, resulted in the alleviation of their inhibitory effect on the urease activity.
authors.affiliation: Department of Botany, Faculty of Science, Mansoura University , Mansoura , Egypt.
authors.forename: Hamed M
authors.initials: HM
authors.lastname: El Shora
authors.affiliation: Department of Botany, Faculty of Science, Kafr El Sheikh University , Kafr El Sheikh , Egypt.
authors.forename: Awatif S
authors.initials: AS
authors.lastname: Ali
mesh_terms: D018548:Cotyledon / Q000201:enzymology; D028464:Cucurbita / Q000201:enzymology*; D003583:Cytokinins / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D014230:Triazoles / Q000378:metabolism*; D014510:Urease / Q000378:metabolism*
chemical_list: D003583:Cytokinins; D007210:Indoleacetic Acids; D014230:Triazoles; D014510:Urease
keywords: Auxins; benzyladenine; brassinosteroids; cordycepin; triazole; urease activity-zeatin