SHORT-TERM LEAF ELONGATION KINETICS OF MAIZE IN RESPONSE TO SALINITY ARE INDEPENDENT OF THE ROOT

The essentiality of roots to the short-term responses of leaf elongation to salinity was tested by removing the roots of maize (Zea mays L.) from the shoots and comparing the initial shortterm response of leaf elongation to that with intact plants. Eight-day-old seedlings growing in solution culture were treated with 80 millimolar NaCl and their leaf elongation rate (LER) was monitored with a linear variable differential transformer connected to a computerized data aquisition system. Initially, LER of intact plants was sharply reduced by salinity, then rose rapidly to reach a new steady-state rate about 1.5 hours after salinization. The new steady-state rate of salinized intact plants was about 80% of the control rate. When the roots of nonsalinized plants were excised under the surface of the nutrient solution, excision did not disturb the steady-state LER. When these shoots were salinized, they responded in a manner nearly identical to that of intact plants, indicating that roots are not essential for the modulation of short-term LER of salt-stressed plants.