Effects of Air Humidity and Air Movement on Growth, Visual Quality and Post-Production Stress Tolerance of Pot Rose 'Toril'

This work aimed at assessing whether a high level of air movement would improve stomatal closure, counteracting the negative effect of high relative air humidity (RH > 85%) on plant growth, visual quality and postharvest stress tolerance to dark and drought (simulating shipping and/or retailing). Pot rose ‘Toril’ was grown at moderate (60%) and high (90%) RH, combined with no additional air movement or with a continuous additional air flow of 0.92 ± 0.03 m s-1 (MOV). At flowering stage, plants were transferred to continuous darkness and without irrigation. Total dry weight and time to flowering were not significantly affected by RH or MOV. MOV did not affect plant height nor flower dry weight, but it significantly increased peduncle diameter by 6%. Plants grown at elevated RH showed a six-fold higher initial transpiration rate at the start of the postharvest period and a reduced longevity (71%) as compared to moderate RH-grown plants. MOV decreased the initial transpiration rate in high RH-grown plants by 23%. In conclusion, high RH had a minimal effect on plant growth and visual quality parameters but it drastically reduced postharvest storability. MOV during growth slightly improved post-production storability in high RH-grown plants, having a minor effect on visual quality.