RELATION OF WATER STRESS MEASURED BY PRESSURE CHAMBER TO THE ROOT REGENERATION ABILITY OF NORWAY SPRUCE (PICEA ABIES (L.) KARST.) TRANSPLANTS

Norway spruce seedlings were lifted several times in the two nurseries. After their exposure to drying for 0, 2, 4 or 6 hours, water content was gravimetrically detected in the above ground parts and roots and by means of the pressure chamber was measured plant moisture stress (PMS). After 3 weeks in the growth chamber, root growth potential (RGP) was determined. The roots of exposed plants lost their water 2 to 3 times faster than the above ground parts. PMS increased from ca 7 bar to more than 25 bar early as after 2 hours of drying. These findings indicate a significant weakening of the physiological state of plants. Strong correlation was observed between the values of PMS and water content in above ground parts and in the roots. Exposing plants to drying significantly worsened regeneration ability their roots (RGP). Both methods of measurement PMS and RGP are useful for evaluating the current physiological state of planting material.