Estimation of growth parameters in salt‐stressed maize: comparison of the pressure‐block and applied‐tension techniques

A custom‐built pressure block was used to estimate the effective turgor (turgor pressure minus the yield threshold) and the cell wall extensibility of the growing zone of the third leaves of 8‐d‐old maize (Zea mays L.) seedlings. In response to cell wall loosening, pressure in the chamber increased rapidly and reached a maximum after approximately 60 min. Plants treated with 80 mol m−3 NaCl for 4 h were compared to control plants. Pressure‐block analysis revealed that salinity reduced effective turgor, but had no effect on cell wall extensibility. These results are qualitatively and quantitatively similar to those obtained with an applied‐tension technique used previously in our laboratory. This study indicates that the pressure‐block and applied‐tension techniques, which use very different methodologies, estimate similar growth parameters.