Net uptake of potassium by low K, high Na cells of Neurospora at pH 5.8 is accompanied by net extrusion of sodium and hydrogen ions. The amount of potassium taken up by the cells is matched by the sum of sodium and hydrogen ions lost, under a variety of conditions: prolonged preincubation, partial respiratory inhibition (DNP), and lowered [K](o). All three fluxes are exponential with time and o...

Rice (Oryza sativa L.) requires adequate potassium (K) nutrition for optimal growth, grain yield, and disease resistance. Studies were conducted in 2001 and 2002 at the Pine Tree Branch Experiment Station (PTBS) to characterize K uptake by rice and investigate the effect of both K-fertilizer application rate and time on rice growth, K uptake, and grain yield. Potassium fertilizer was applied at...

The Na+-K+ pump activity was determined in femoral arterial smooth muscle from deoxycorticosterone acetate (DOCA)-salt hypertensive rats using potassium relaxation and ouabain-sensitive 86Rb uptake as indices. The membrane-stabilizing effect of calcium and its relation to Na+-K+ pump activity also were examined. Femoral arteries from DOCA-salt rats exhibited a greater relaxation in response to ...

The regulation of intracellular ion concentrations is a fundamental property of living cells. Although many ion transporters have been identified, the systems that modulate their activity remain largely unknown. We have characterized two partially redundant genes from Saccharomyces cerevisiae, HAL4/SAT4 and HAL5, that encode homologous protein kinases implicated in the regulation of cation upta...

Ion and oxygen uptake were studied on aging bean stem slices. Oxygen uptake was high immediately after slicing, decreased to a minimum at 100 minutes, and then increased again. Ion uptake per unit of O(2) uptake data suggested that metabolic energy was utilized almost exclusively for sodium transport in fresh tissue but was diverted to potassium transport as the slices aged. Oxygen and ion upta...

The amino acid carriers in sugarcane suspension cells were characterized for amino acid specificity and the stoichiometry of proton and potassium flux during amino acid transport.Amino acid transport by sugarcane cells is dependent upon three distinct transport systems. One system is specific for neutral amino acids and transports all neutral amino acids including glutamine, asparagine, and his...