Effects of CO₂ Enrichment on Yields and Preservability of Cut Flowers in Phalaenopsis

Abstract

The effect of CO₂ enrichment on Phalaenopsis cut flower production was examined for 30 months throughout five flowering cycles. The plant was cultured in three greenhouses with different CO₂ levels of (A) : control, daily mean of ambient air=438 ppm; (B) : 700 ppm; and (C) : 1000 ppm.
1. The fresh weight of cut flowers, the numbers of inflorescence and flowers per 20 plants varied, depending on the CO₂ concentration for each flowering cycle.
2. The preservability (vase life) of cut flowers always improved under higher CO₂ levels. Organic acid contents of plants were also higher under higher CO₂ levels. The malic acid content in the flowers was higher than in the younger leaf and flower stalk at 1:00 PM and 10:00 PM; and it was also higher in the younger leaf than in the flower stalk at 10:00 PM, but lower at 1:00 PM.
The pH value of plants was always lower at higher ambient CO₂ levels, and lower in the younger leaf and flower stalk at 1:00 PM than at 10:00 PM, wheras at those same times the sugar content at the higher ambient CO₂ levels reached its maximum.