Aerial environment and light quality during production affect postharvest transpiration of ornamentals

Production of ornamentals in greenhouses under high air humidity (RH) conditions (>85%) induce malfunctional stomata and uncontrolled waterloss. Drought during shipping and retailing may result in reduced shelf life and marketability. In this study we evaluated how CO2 concentration and light quality (visible light and UV radiation) in combination with high and moderate RH regimes affect transpiration during production and postproductionofthe economically important ornamentals poinsettia (Euphorbia pulcherrima) and pot rose (Rosa x hybrida). By enriching the air with CO2 (800 ppm) transpiration during growth was reduced compared to ambient levels (400ppm) but postharvest transpiration was found to be higher compared to growing at ambient CO2 levels. Plants produced under high RH and high CO2 was found to have the highest postharvest transpiration.The interaction between RH and light quality was studied by growing poinsettias and roses in moderate (60%) and high RH (90%) withdifferent lamp types (light emitting diodes, high pressure sodium + UV lamps) providing different spectral distributions. A light spectrum with little blue light (5%) caused higher postharvest transpiration compared with a light sourcecontaining more blue light (20%). The combination of high RH and high pressure sodium (HPS) enriched with UV-B radiation (280-320 nm) during growth led to higher postharvest transpiration compared to HPS alone but no effect of UV-B was observed under moderate RH (60%). Cultivation strategies to avoid malfunctional stomata under high RH conditions are also discussed. SourceAERIAL ENVIRONMENT AND LIGHT QUALITY DURING PRODUCTION AFFECT POSTHARVEST TRANSPIRATION OF ORNAMENTALSArve, LE1, Terfa, MT1, Suthaparan, A1, OlsenJE1, Gisler?d, HR1, Mortensen, L1,Torre, S1sissel.torre@umb.no1Norwegian University of Life Sciences, ?s, NorwayIHC 2014, International Horticulture Congress, 17-22 August 2014, Brisbane,http://www.ihc2014.org/Picture by trabajoova2013.blogspot.com