 Zantedeshia species and their hybrids are NZ's second largest export crop for cut flowers, featuring a range of flower colours that vary from maroon/dark red through pink, to orange, yellow, cream and white. Flower colour is an important factor in the appeal of any ornamental crop and information about the pigments present in a particular plant is necessary for the development of new colour varieties, but also offers some indicators as to the lineage of varieties that already exist. No information is currently available on the pigments that make up the colours seen in Zantedeschia flowers, so as part of a project on flower colour in Zantedeschia, we analysed the flavonoid and carotenoid pigment profiles in several commercial cultivars. MethodsMature flowers (spathe plus spadix) from eight Zantedeschia cultivars were sampled from commercial crops. The cultivars chosen cover the broad categories of flower colour seen in the photo above. Spathe colour was measured, tissue samples taken, and freeze dried. Flavonoid, and carotenoid pigments were extracted and quantified spectrophotometrically. The anthocyanins (coloured flavonoids) and other flavonoids were analysed separately. Individual pigments were separated by HPLC.  ResultsFlowers from the cultivars pictured above illustrate the depth and intensity of colour seen in this crop. As well, at left, the spatial separation of the pigment types within a cross section of spathe tissue from Majestic Red is illustrated. Anthocyanins were the major pigment in red and pink cultivars, and carotenoids in yellow cultivars. Both pigments were present in orange cultivars. Within the white coloured 'Albomaculata' neither anthocyanins nor carotenoids were present. Flavonoid pigments were detected in this cultivar, as with all cultivars examined. Variations in colour between cultivars were primarily due to changes in pigment concentration and pigment type present, and the identity of individual pigments did not vary widely between cultivars. As illustrated above, the anthocyanins were restricted to one or two cell layers immediately below the epidermis and accumulated in the vacuole, giving the appearance of filling the entire cell. In cross section of the flower spathe the carotenoids were more evenly spread across most of the cell layers. They accumulated within the chromoplast and were seen as distinct globules within a cell. Orange cultivars such as 'Mango' had the anthocyanin pigment overlaying the carotenoid pigments. The overlay was not continuous however, giving a somewhat speckled appearance. This summary has been taken from a poster presented to the NZ Institute of Agri. Sci. and the NZ Soc. for Hort. Sci. Annual Convention, Lincoln University, Canterbury. 27 - 29 June, 2001, and will form the basis of a paper to be presented at the Intl. Hort. Congress, Toronto. 11 – 17 August, 2002.  Pictured at right are some of the research team involved; (right to left) David Lewis (Crop & Food Research), Dr Keith Funnell (insert; Massey), Dr Sheng-Chung Huang (Taichung District Agricultural Improvement Station, Taiwan) and Carolina Carrillo (Massey student). Carolina wasn't involved in this project, but was involved with other Zantedeschia research. Not pictured here are Mr H Arathoon (Crop & Food Research) and E Swinny (Industrial Research). In part, this research was carried out by a visiting scientist (Sheng-Chung, pictured above) as a research project relating to a period of sabbatical leave. If you would like to know about this research project or other research opportunities as a student, visitor or potential sponsor, please e-mail me at <K.Funnell@massey.ac.nz> to enquire further. |
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