Effect of Light and Temperature through Poly Film Covers on Anthocyanin Content in Rose Cut Flowers

Abstract

Quality is the most important attribute in rose cut flowers for both export and domestic market. Quality in cut flowers may be defined by many attributes however, among the most important is colour. A group of pigments commonly known as anthocyanins determine colour in plants. Anthocyanins play a significant role by ameliorate the effect of high irradiance in plants under stressful environment. They also play a key role in delaying senescence hence enhancing the cut flower vase life. Despite the advantages anthocyanins are affected by the preharvest conditions mainly light and temperature interfering with their stability. An experiment was set up to investigate the effect of light and temperature through selected coloured poly film covers on rose petal anthocyanin content. The greenhouse structure was covered by poly films of different colours that were compartmentalized i.e. UV-A clear, IR504 with yellow tint and UV-A 205/N with green tint replicated three times. Two rose cultivars Red calypso and Furiosa were established and maintained, upon maturity the flower heads were plucked and oven dried at 60°C to constant weight. 5 g of the crushed petals was used in anthocyanin extraction. The anthocyanins were extracted and quantified in comparison with commercial standards using HPLC machine. The data obtained from the chromatogram as peak areas was subjected to analysis of variance (ANOVA) using SAS statistical package (SAS Inst., Inc., Cary, NC) at P = .05. Where there were treatment differences, mean separation was done using Tukey’s procedure. Poly films significantly affected the quantity and quality of anthocyanin accumulation in rose petals. Cyanidin 3-0-glucoside was the most prevalent anthocyanin across all poly film covers and it was noted to be high under the UV-A 205/N (110.95±8.26 μg _ 5 g–1 DW) and IR504 (109.69±8.26 μg _ 5 g–1 DW) compared to UV-A clear (84.56± 8.26 μg _ 5 g–1 DW). The quantity of anthocyanins was low under the UV-A clear poly film that was characterized by high light transmission and day temperature. Combination of high irradiance and temperature affect the quality and quantity of anthocyanin in rose cut flowers.