GROWTH-CHARACTERISTICS AND BIOCHEMICAL-CHANGES OF POPLAR SHOOTS IN-VITRO UNDER SODIUM-CHLORIDE STRESS

The effect of NaCl on poplar shoots grown in vitro was studied. After 28 days of cultivation on media containing up to 300 mmol/L NaCl, the shoot and root lengths as well as the rooting percentage were smaller than in the control. These effects were enhanced by increasing salinit y. Changes in several biochemical markers (soluble proteins,soluble su gars and peroxidase activity) were observed in poplar shoots cultivate d for 7 days on salt-supplemented and control media. Measurements show ed that the soluble protein content of the plants decreased dramatical ly on day 1 but stabilized to a constant value thereafter, except for the 300 mmol/L NaCl condition. Peroxidase activity increased with salt Content and time of cultivation, except for the 300 mmol/L NaCl condi tion, where it remained unchanged. Changes were also observed in the c ontents of glucose, fructose, sucrose and galactose. Glucose and fruct ose contents strongly increased after 3 days of cultivation on 300 mmo l/L NaCl-containing medium. A maximum sucrose content was observed on day 1 for all conditions, followed by a decrease until day 7. Galactos e was unaffected by the salt treatments.