The initial rate of (2-(14)C)acetic acid (AA) uptake by corn roots was used for probing the dependency of the root cell surface pH on H(+) excretion. AA influx was linearly related to AA concentration, dependent on the concentration of the undissociated form (AH), unaffected by variations of the membrane potential, and was thus assumed to result mainly from the free diffusion of AH across the m...

The disruption of K(+) transport and accumulation is symptomatic of NH(4)(+) toxicity in plants. In this study, the influence of K(+) supply (0.02-40 mM) and nitrogen source (10 mM NH(4)(+) or NO(3)(-)) on root plasma membrane K(+) fluxes and cytosolic K(+) pools, plant growth, and whole-plant K(+) distribution in the NH(4)(+)-tolerant plant species rice (Oryza sativa L.) was examined. Using th...

In an accompanying paper [2], we developed the Shorten [3] model of skeletal muscle by incorporating equations such as surface calcium fluxes. further research in this paper, succeeded reproducing cramp, well its prevention and reversal, investigating contraction which regulatory networks are involved, using extended comparison with original model. Incorporation data from a traditional medicine...

Futile plasma membrane cycling of ammonium (NH4 ) is characteristic of low-affinity NH4 + transport, and has been proposed to be a critical factor in NH4 + toxicity. Using unidirectional flux analysis with the positronemitting tracer N in intact seedlings of barley (Hordeum vulgare L.), it is shown that rapid, futile NH4 + cycling is alleviated by elevated K supply, and that low-affinity NH4 + ...

Exogenous abscisic acid (ABA) is known to either stimulate or inhibit root growth, depending on its concentration. In this study, the roles of ethylene and auxin in this biphasic effect of ABA on root elongation were investigated using chemical inhibitors and mutants. Inhibitors of ethylene perception and biosynthesis and an auxin influx inhibitor were all found to block the inhibitory effect o...

• We report the first use of tracer 13 NH 4 + ( 13 N-ammonium) efflux and retention data to analyse subcellular fluxes and compartmentation of NH 4 + in the leaves of a higher plant (wheat, Triticum aestivum ). • Leaf segments, 1–2 mm, were obtained from 8-d-old seedlings. The viability of the segments, and stability of NH 4 + acquisition over time, were confirmed using oxygen-exchange and NH 4...

In a previous article [7], the author proves that value of root number varies in non-isotrivial family elliptic curves indexed by one parameter t running through $${\mathbb {Q}}$$ . However, well-known example Washington has $$-1$$ for every fiber when runs {Z}}$$ Such examples are rare since, as proven this paper, integer fibers large class families curves. This result depends on squarefree co...

We used genetic and molecular approaches to identify mechanisms by which the gaseous plant hormone ethylene reduces lateral root formation and enhances polar transport of the hormone auxin. Arabidopsis thaliana mutants, aux1, lax3, pin3 and pin7, which are defective in auxin influx and efflux proteins, were less sensitive to the inhibition of lateral root formation and stimulation of auxin tran...