This study determined whether the field level concentration of root zone CO2 affects transpiration rate and root water transport in soybean (Glycine max L. Merr.). In an upland field converted from a paddy field, topsoil CO2 during the cropping season rose to 8 kPa of partial pressure after rainfall, whereas O2 dropped only to a minimum of 7 kPa. An elevated root zone CO2 pressure of 6 kPa sign...

Heterogeneity in root-zone temperature both vertically and horizontally may contribute to the uneven vegetative and reproductive growth often observed across vineyards. An experiment was designed to assess whether the warmed half of a grapevine root zone could compensate for the cooled half in terms of vegetative growth and reproductive development. We divided the root system of potted Shiraz g...

Suaeda fruticosa (L.) Forssk plants grown in saline conditions (200 to 400 mol m!3 NaCl) had greater fresh and dry weights than those grown in non-saline controls, and 600 to 1000 mol m!3 NaCl inhibited growth. Gibberellic acid and kinetin both alleviated some of the inhibitory effects of salinity at 800 mol m!3 NaCl on shoot growth of S. fruticosa while root growth was promoted by kinetin. Tis...

Roots are very sensitive to hypoxia and adapt effectively to a reduced availability of oxygen in the soil. However, the site of the root where oxygen availability is sensed and how roots acclimate to hypoxia remain unclear. In this study, we found that the root apex transition zone plays central roles in both sensing and adapting to root hypoxia. The exposure of cells of the root apex to hypoxi...

Diel and seasonal variations in denitrification were determined in a littoral lake sediment colonized by the perennial macrophyte Littorella uniflora (L.) Aschers. In the winter, the activity was low (5 mumol of N m h) and was restricted to the uppermost debris layer at a depth of 0 to 1 cm. By midsummer, the activity increased to 50 mumol of N m h and was found throughout the root zone to a de...

Root exudates have important, yet incompletely known, roles in plant physiology, mainly in rhizosphere interactions with other organisms. Proline might play a critical role in protecting plants under stress, particularly under saline conditions. However, as far as we know, no attempts have been made to determine the proline content of root exudates. Here, we present preliminary results of the q...