Abstract: The quick response in transpiration to salt shock was observed in willow ( Salix babylonica L. ) plantlet. It was shown that a hydraulic signal aroused in root which was quickly transmitted to shoot when the root was treated with NaC1 100 to 500 mmol/L. In response to the hydraulic signal, water was withdrawn from the shoot; the transpiration rate of the shoot consequently increased 8 to 15 times the initial level within 1 to 2 s and followed a decline to its initial level or even lower. Moreover, electrical wave transmission (at the rate of 28 to 120 mm•s- 1 ) was recorded on the shoot about 2 min after the initial rise in transpiration, which might be an indication of active adjustment of the shoot in checking excessive water expenditure.

Key words: Hydraulic signals, Electrical wave, Transpiration rate, Salix babylonica, Salt shock