منابع مشابه
Absorption of Magnesium and Chloride by Excised Corn Roots
Absorption characteristics of Mg2+ and Clwere investigated with 5-day-old excised corn (Zea inays) roots. Uptake from both 0.5 and 10 milliequivalents per liter MgCl2 solutions occurred at steady state rates for the first 6 hours. Inhibition by dinitrophenol and low temperatures established that absorption during this period was metabolically mediated in the absence and presence of Ca2+. Absorp...
متن کاملEffects of temperature on orthophosphate absorption by excised corn roots.
The uptake of orthophosphate ((32)P) by excised corn roots, Zea mays L. was studied using roots grown on 0.2 mm CaSO(4). Nine concentrations of KH(2)PO(4) from 1 to 256 mum were used at temperatures of 20 degrees , 30 degrees , and 40 degrees . Enzyme kinetic analysis was applied to the data obtained. Two apparent mechanisms (sites) of phosphate uptake were observed, 1 dominating at high P conc...
متن کاملSynthesis and turnover of nitrate reductase in corn roots.
THE INDUCTION AND REINDUCTION OF NITRATE REDUCTASE IN ROOT TIP OR MATURE ROOT SECTIONS SHOW ESSENTIALLY A SIMILAR PATTERN: a lag, a period of rapid increase in enzyme activity and finally a period of relatively minor change. Both inductions are sensitive to 6-methylpurine and cycloheximide. Kinetic studies with 6-methylpurine suggest that the half-life of the messenger RNA for nitrate reductase...
متن کاملEffect of l-Canavanine on Nitrate Reductase in Corn Roots.
l-Canavanine inhibits the appearance of nitrate reductase (NADH-nitrate oxidoreductase, EC 1.6.6.1) in both root tips and mature root sections of corn (Zea mays L.). Ten-fold more canavanine was required to cause a 50% reduction in the level of nitrate reductase activity (NRA) in root tips than in mature root sections. For example with one particular batch of seeds 500 mum canavanine was effect...
متن کاملCalcium inhibition of potassium absorption in corn roots.
Calcium (or magnesium) sulfate or chloride was found to inhibit energy dependent potassium transport in excised corn roots. This Ca(2+) inhibition of K(+) transport was most pronounced during the initial phases of transport. As the absorption periods were lengthened the effect of Ca(2+) gradually changed from an inhibition to a typical promotion (after about 30-45 mins) of K(+) transport. Kinet...
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ژورنال
عنوان ژورنال: Plant Physiology
سال: 1988
ISSN: 0032-0889,1532-2548
DOI: 10.1104/pp.86.3.759