Effects of Light Spectra on Quality, Morphology and Photosynthesis Characteristics of Anthurium (Anthurium andraeanum) Cut Flower under Cold Storage Condition

Postharvest handling of tropical flowers is usually difficult due to their sensitivity to cold temperatures. Anthurium(Anthurium andraeanum)is a tropical plant used in ornamental industry for its beautiful spathe and leaves. It can be produced in wide ranges of climates; in locations far away from their original habitats in greenhouses. Although, anthurium has long vase life compared to other cut flowers, postharvest exposure to cold temperatures makes some restrictions on its desirable vase life. This study aimed to investigate the effects of different light spectra on postharvest performance of anthurium cut flowers. Cut flowers of Anthurium andraeanum cultivars with red ('Calore') and white ('Angel') spathes were obtained from a commercial anthurium greenhouse on the morning. Anthurium cut flowers were harvested when 40-50% of the spadix true flowers were fully opened. Each flower was placed in closed flasks containing 500 mL water. Sixty flasks with cut flowers (30 cut flowers from each cultivar) were placed into chambers with exactly similar conditions but with different light spectra including white (W), blue (B), red (R) and 70% R+30% B (RB) provided by LED production modules and darkness. Each flower under light spectra was inspected and the vase life of the all flowers, change in spathe angel, spathe area, maximum quantum yield of photosystem II (Fv/Fm) and fluorescence decline ratio (RFD) were measured during 14 days exposure to 4 °C storage. Spathe 'angel' seven and 14 days following exposure to cold storage was dramatically increased in B light while the lowest changes were observed in R light of the both cultivars. Vase life of anthurium cut flowers were significantly (P≤0.01) influenced by the interaction between light spectra and cultivars. Among the light spectra, the longest vase life were observed in spathes exposed to R light in both cultivars. In 'Angel', exposure to B light dramatically shortened the vase life of anthurium cut flowers in comparison with the other light spectra. A positive relationship was detected between spathe area and vase life of cut flowers, while the relationship between spathe 'angel' and vase life was negative. No photosynthetic activity was detected on the spathe of anthurium, but the peduncle of anthurium showed the photosynthetic activity. The highest Fv/Fm and RFD values were detected in darkness and the lowest values for Fv/Fm and RFD were observed in R and RB-exposed spathes. No relationships was observed between the photosynthetic activities and the vase life of anthurium cut flowers. Although there are some reports confirmed the importance of plant growth under different light spectra on its postharvest quality, there is no report regarding the effects of light spectra on the quality of cut flowers in postharvest stage. Similar to anthurium, some reports indicated that there is no relationship between the photosynthesis and the quality of harvested products. Exposure of anthurium cut flowers to different light spectra resulted in alterations of morphology and quality during exposure to low temperatures. B spectrum had strong negative effects on the morphology and quality of anthurium cut flowers, while exposure to R light resulted in improvement of quality of anthurium cut flowers with less negative effects on their morphology. Spathe of anthurium had no photosynthetic activity, while its peduncle showed the photosynthetic activity. There were significant relationships between morphology and vase life of anthurium cut flowers, while no relationships were found between photosynthetic activity and their vase life. In conclusion, lighting environment during postharvest of anthurium cut flowers should be take into account for keeping their quality under low temperature conditions. Red light spectrum was introduced as the best light treatment to reduce chilling injury, increase the vase life and maintain the quality of anthurium cut flowers in both cultivars.