The pitcher plant, Sarracenia L., is becoming an important potted plant, and several breeding programs are creating interspecific hybrids with improved leaf and flower colors (Gardner, 2000). Three different types of pigments - chlorophyll, flavonoids, and carotenoids — are responsible for flower and leaf color (Griesbach, 1984). The red flowers and leaves of Sarracenia are due to flavonoid pigments, which can be subdivided into the anthocyanins and co-pigments. In vitro, the anthocyanins are colored red through blue, while the co-pigments appear white through pale yellow.     

Romeo et al. (1977) identified the co-pigments kaempferol and quercetin in the leaves of S. alata Wood, S. flava L., S. Ieucophylla Raf., S. minor Walt., S. oreophila (Kearney) Wherry, S. psittacina Mich., S. purpurea L., and S. rubra Walt. Unidentified leucoanthocyanidins occur in the leaves of S. flava, S. leucophylla, S. minor, S. psittacina, and S. purpurea (Jay and Lebreton, 1972).  Further studies (Schnell, 1978), using thin layer chromatography, found seven red and six blue anthocyanins in the petals of S. leucophylla, S. rubra, S. psittacina, and S. purpurea. Based upon additional biochemical data, the existence of pelargonidin and cyanidin was predicted (Sheridan and Mills, 1998).

We obtained leaf and flower samples of S.flava, S. leucophylla, S. psittacina, S. purpurea, and S. rubra from several different geographic sites. The anthocyanins were isolated by high-performance liquid chromotagraphy (HPLC) as previously described (Griesbach, et al., 1999). The isolated anthocyanins were acid-hydrolyzed to release the corresponding anthocyanidins, which were then analyzed by HPLC and characterized by diagnostic spectrophotometry as previously described (Griesbach, 1999).

The anthocyanins from the various species were compared by co-elution on HPLC. The HPLC profiles for the different accessions of the same species were identical. Sarracenia purpurea contained all of the anthocyanins that were found in the other species. Because of the ready availability of S. purpurea leaves and flowers, the anthocyanins were characterized using pigments isolated from this species (Table 1).

Cyanidin was the only anthocyanidin found in leaves of all the species examined, and was also the only one present in the petals of S. rubra and S. leucophylla (Table 2). Both cyanidin and delphinidin were found in petals of S. psittacina and S. purpurea (Table 2).  A large quantity (44%) of delphinidin was present in S. purpurea petals, while a smaller quantity (11%) was present in S. psitticina. Sarracenia flava has yellow flowers and contained no anthocyanidins.  Romeo et. al. (1977) reported that quercetin glycosides were the principal flavonols present in Sarracenia. In the biochemical pathway, dihydroquercetin is a precursor of both quercetin and cyanidin. Therefore, we expected to find cyanidin as the principal anthocyanidin in Sarracenia leaves and flowers. Romeo et al. ( 1977) found a small amount of kaempferol in Sarracenia, but we did not detect pelargonidin, which is derived from dihydrokaempferol. This also was not unexpected because many Petunia x hybrida Hort. Vilm. cultivars contain small amounts of kaempferol and produce no pelargonidin (Griesbach and Asen, 1990; Griesbach et al.,1991).     

Table 1. Retention time on HPLC and spectral properties of purified standards and the anthocyanidins extracted from Sarracenia purpurea flowers in the HPLC profile of S. purpurea, peak #1 corresponded to delphinidin and peak #2 to cyanidin.

Table 2. Cyanidin and delphinidin in red-flowered petals of four Sarracenia
species as a percent-age of total anthocyanidins. (Means for three samples +/- SD).

The discovery of delphinidin was not unexpected since Schnell (1978) had reported the presence of blue pigments in S. psittacina and S. purpurea. This current study identifies those blue pigments as delphinidin glycosides. Schnell, using TLC analysis, reported the presence of 13 different floral pigments.  Our HPLC profiles of the floral anthocyanins of S. rubra and S. leucophylla before hydrolysis showed only a single anthocyanin peak (data not shown). In S. purpurea and S. psitticina, five different anthocyanin peaks were present, two of which were present in only trace amounts (data not shown). Many of the 13 pigments reported by Schnell were probably breakdown products. Further studies are needed to identify the sugar(s) attached to the two major anthocyanidins.

Literature Cited

Gardner, R. 2000. Building a better pitcher plant. 

Griesbach, R.J. 1984. Effects of carotenoid anthocyanin combinations on flower color J. Hered.   75: 145-147.

Griesbach, R.J. and S. Asen. 1990. Characterization of the flavonol gytcosides in Petunia. Plant Sci. 70:49-56.

Griesbach, R.J., S. Asen, and B.A. Leonhardt.1991.  Petunia hybrida anthocyanins acylated with caffeic acid. Phytochemistry 30:1729-1731.

Griesbach, R.J., J.R. Stehman, and F. Meyer.1999.   Anthocyanins in the "red" flowers of Petunia exserta. Phytochemistry 51 :525-528.

Jay, M. and P. Lebreton. 1972. Chemotaxonomic  research on vascular plants 26. The flavonoids of the Sarraceniaceae, Nepenthaceae, Droseraceae and Cephalotaceae: A critical study of  the order Sarraceniales. Naturaliste Canadienne 99: 607-613.

Romeo, J.T., J.D. Bacon, and T.J. Mabry. 1977. Ecological considerations of amino acids and flavonoids in Sarracenia species. Biochem. Syst.Ecol.5: 117-120.

Schnel1, D.E. 1978. Sarracenia L. petal extract chromatography. Castanea 43: 107- 115.

Sheridan, P. and R. Mills. 1998. Presence of  proanthocyanidins in mutant green Sarracenia indicate blockage in late anthocyanin biosynthesis between leucocyanidin and pseudobase.  Plant Sci. 135:11-16.

Received for publication 23 Mar. 2000 Accepted for publication 2 Aug. 2000. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.

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