SEASONAL-CHANGES IN THE TRANSIENT EXPRESSION OF A 35S CAMV-GUS GENE CONSTRUCT INTRODUCED INTO SCOTS PINE BUDS

Seasonal changes in the transient expression of beta-glucuronidase gen e (GUS) driven by a constitutive 35S CaMV-promoter in Scots pine (Pinu s sylvestris L.) buds were studied by the microprojectile DNA-delivery method. Buds were collected from 5-, 15- and 50-year-old trees. In bu ds from all age groups the amount of transient expression was dependen t on the season; the highest values were found in March, and values we re lowest both at the beginning and at the end of the growing season. Pretreatment with growth regulators increased both the amount of trans ient GUS expression and arginine decarboxylase (ADC) activity in buds indicating an increase in metabolic activity. These results confirm th at the genetic transformation technique can be used to study seasonall y dependent regulation in mature Scots pine tissues.