Wednesday, August 1, 2012
Grand Ballroom
The objective of this research was to investigate how the variation in bicarbonate (HCO3-) concentration in fertilizer solution influences the growth, stolon (daughter plant) production, and development of physiological disorders during the vegetative propagation of 'Seolhyang' strawberry plants. Cold-treated mother plants at 3 true-leaf stage were transplanted into wooden boxes (30 cm x 30 cm, 20 cm deep) containing coir dust + perlite (7:3, v/v) and fertilized with a modified Hoagland solution containing 60, 90, 120, 180 and 240 mg·L-1 of HCO3- as a constant feed as needed. The electrical conductivity (EC) in the nutrient solution was maintained at around 1.2 dS·m-1. The deficiency symptoms for B, Zn and Fe appeared on mother plants 60 days after transplanting in the treatments with 240 mg·L-1 HCO3-. The deficiency symptoms in this treatment were spread to all plant parts including newly formed stolons in 90 days after transplanting. The treatments with 60 and 90 mg·L-1 HCO3- did not show significant difference in mother plant growth. When determined 120 days after transplanting, HCO3- concentrations higher than 120 mg·L-1 suppressed mother plant growth with reduced leaf numbers, chlorophyll contents and fresh weights. Plant growth suppression became more severe as HCO3- concentrations were elevated. In 120 days of treatment, the number of daughter plants produced per mother plant was 23 and 13 in the treatments with 60 and 240 mg·L-1 HCO3-, respectively. The fresh weight and total length of newly formed stonons per mother plant decreased from 185.2 g and 853 cm to 123.6 g and 544 cm, respectively, when HCO3- concentration was increased from 60 mg·L-1 to 240 mg·L-1 in nutrient solution. The result of this study shows that elevated nutrient HCO3- concentrations are detrimental to the growth and production of new stolons by 'Seolhyang' strawberry plants during the vegetative propagation phase.