Aluminum (Al) is toxic to plants when solubilized into Al(3+) in acidic soils, and becomes a major factor limiting plant growth. However, the primary cause for Al toxicity remains unknown. Nitric oxide (NO) is an important signaling molecule modulating numerous physiological processes in plants. Here, we investigated the role of NO in Al toxicity to Hibiscus moscheutos. Exposure of H. moscheuto...

The modification of root traits in relation to nitrate uptake represents a source for improvement of nitrogen uptake efficiency. Because ethylene signalling modulates growth of exploratory and root hair systems more rapidly (minutes to hours) than nitrate signalling (days to weeks), a pharmacological approach was used to decipher the relationships between root elongation and N uptake. Rape seed...

Lateral roots of intact summer squash seedlings (Cucurbita pepo L.) were used to quantify the effects of boron deficiency on DNA synthesis, protein synthesis, and respiration. The temporal relationship between changes in these metabolic activities and the cessation of root elongation caused by boron deprivation was determined. Transferring 5-day-old squash seedlings to a hydroponic culture medi...

Cd (cadmium) stress always alters the homeostasis of ROS (reactive oxygen species) including H2O2 (hydrogen sulfide) and [Formula: see text] (superoxide radical), leading to the oxidative injury and growth inhibition in plants. In addition to triggering oxidative injury, ROS has been suggested as important regulators modulating root elongation. However, whether and how Cd stress induces the inh...

Phytotoxicity of aluminum is characterized by a rapid inhibition of root elongation at micromolar concentrations, however, the mechanisms primarily responsible for this response are not well understood. We investigated the effect of Al on the viscosity and elasticity parameters of root cell wall by a creep-extension analysis in two cultivars of wheat (Triticum aestivum L.) differing in Al resis...

Root elongation and cell expansion were decreased markedly by pH& 6±0 compared to pH 5–5±5 in Lupinus angustifolius but only slightly in Lupinus pilosus and Pisum satiŠum. We tested whether poor root growth of L. angustifolius at high pH correlates with decreased proton extrusion or increased membrane permeability by comparing effects of pH on intact and excised roots of L. angustifolius, L. pi...

Soil alkalinity causes major reductions in yield and quality of crops worldwide. The plant root is the first organ sensing soil alkalinity, which results in shorter primary roots. However, the mechanism underlying alkaline stress-mediated inhibition of root elongation remains to be further elucidated. Here, we report that alkaline conditions inhibit primary root elongation of Arabidopsis (Arabi...

Slight changes in the concentration of ethylene in the environment modulate the elongation of target cells in the root epidermis of Arabidopsis. The response is immediate, concentration dependent, and reversible on root base but irreversible on cell base, whereas cell differentiation is not affected. We suggest that in natura ethylene is a means of fine and fast tuning of root elongation. In Ar...

Excised Pisum sativum L. root tips were incubated in a pH 5.2 sucrose medium containing abscisic acid. Elongation growth was inhibited by 100 mum abscisic acid. However, decreasing the abscisic acid concentration caused stimulation of elongation, the maximum response (25% to 30%) occurring at 1 mum abscisic acid. Prior to two hours, stimulation of elongation by 1 mum abscisic acid was not detec...

Root elongation requires cell divisions in the meristematic zone and cell elongation in the elongation zone. The boundary between dividing and elongating cells is called the transition zone. In the meristem zone, initial cells are continuously dividing, but on the basal side of the meristem cells exit the meristem through the transition zone and enter in the elongation zone, where they stop div...