Phosphorus plays a critical role in cellular biology (5). Many cellular processes require phosphorus in one form or another and include nucleic acid synthesis and metabolism (37), energy metabolism (42, 46), cellular signaling (38), membrane integrity (53, 58), muscle function (10, 33), enzyme activity (74), lipid metabolism (25), and bone mineralization (30). Phosphorus is present in virtually...

Characterization of nodule growth and functioning, phosphorus status of plant tissues and hostplant growth of nodulated soybean (Glycine max L. Merr.) plants grown under different phosphorus conditions was studied in order to evaluate the role of phosphorus in symbiotic nitrogen fixation. Phosphorus deficiency treatment decreased the whole plant fresh and dry mass, nodule weight, number and fun...

Biological productivity in many ocean regions is controlled by the availability of the nutrient phosphorus. In the Mediterranean Sea, aerosol deposition is a key source of phosphorus and understanding its composition is critical for determining its potential bioavailability. Aerosol phosphorus was investigated in European and North African air masses using phosphorus near-edge X-ray fluorescenc...

Dark-grown dicotyledonous seedlings form a hook-like structure at the top of the hypocotyl, which is controlled by the hormones auxin and ethylene. Hook formation is dependent on an auxin signal gradient, whereas hook exaggeration is part of the triple response provoked by ethylene in dark-grown Arabidopsis seedlings. Several other hormones and light are also known to be involved in hook develo...

The requirement of auxin for the ethylene-mediated growth response in the root of Arabidopsis thaliana seedlings was investigated using two ethylene-resistant mutants, aux1-7 and eir1-1, whose roots have been shown to have a defect in the auxin influx and efflux carriers, respectively. A 50% inhibition of growth (I(50)) was achieved with 0.84 microl liter(-1) ethylene in wild-type roots, but 71...

Auxin is of vital importance in virtually every aspect of plant growth and development, yet, even after almost a century of intense study, major gaps in our knowledge of its synthesis, distribution, perception, and signal transduction remain. One unique property of auxin is its polar transport, which in many well-documented cases is a critical part of its mode of action. Auxin is actively trans...

In plants, the developmental mechanisms that regulate the positioning of lateral organs along the primary root are currently unknown. We present evidence on how lateral root initiation is controlled in a spatiotemporal manner in the model plant Arabidopsis thaliana. First, lateral roots are spaced along the main axis in a regular left-right alternating pattern that correlates with gravity-induc...

BACKGROUND AND AIMS The root meristem of the Arabidopsis thaliana mature embryo is a highly organized structure in which individual cell shape and size must be regulated in co-ordination with the surrounding cells. The objective of this study was to determine the role of the AUX1 LAX family of auxin import carriers during the establishment of the embryonic root cell pattern. METHODS The radic...

Increases in serum phosphorus levels and dietary phosphorus intake induces vascular calcification, arterial sclerosis and cardiovascular diseases. Limiting phosphorus intake is advisable, however, no assessment methods are capable of estimating dietary phosphorus intake. We hypothesized that urinary phosphorus excretion can be translated into estimation of dietary phosphorus intake, and we eval...

Dietary phosphorus control is often a main strategy in the management of patients with chronic kidney disease. Dietary protein is a major source of phosphorus intake. Recent data indicate that imposed dietary phosphorus restriction may compromise the need for adequate protein intake, leading to protein-energy wasting and possibly to increased mortality. The two main sources of dietary phosphoru...