Chromatographic and Spectrophotometric Analyses of the Photosynthetic Pigments of the Gametophyte and the Sporophyte of Lophocolea heterophylla

Abstract

Chromatographic and spectrophotometric analyses of the plastid pigments of Lophocolea heterophylla reveal that both the gametophyte and the young sporophyte possess the following: chlorophyll a, chlorophyll b, neoxanthin, violaxanthin, lutein, zeaxanthin, and p-carotene. Although there are no qualita- tive differences, quantitatively the concentration of total chlorophylls is signifi- cantly greater in the sporophyte than in the gametophyte. It is accepted as common knowledge among hepaticologists that the same photosyn- thetic pigments present in the leaves of flowering plants are found in the gametophytes of liverworts; and further, that the green pigmentation in the early stages of development of liverwort sporophytes reflects the presence of chlorophyll. A search in the literature reveals some supporting experimental evidence for these assertions. Strain (1958) used column chromatography to separate the photosynthetic pig- ments present in the thalli (gametophytes) of Asterella californica, Conocephalum conicum, and Marchantia polymorpha. He reported that these liverworts yielded the same primary photosynthetic pigments observed in leaves of flowering plants: chloro- phyll a, chlorophyll b, violaxanthin, neoxanthin, lutein, zeaxanthin, and p-carotene with or without a-carotene (a-carotene is absent in M. polymorpha). The presence of carotenoids in M. polymorpha had been reported earlier by Kohl (1902). Using thin-layer chromatographic techniques, Herrmann (1968) found 1) quanti- tative differences in the photosynthetic pigments present in thalli of Sphaerocarpos donnellii grown in different environments but none between the photosynthetic pigments present in male and female gametophytes grown in the same environment, and 2) the presence of two cis-trans-isomers of p-carotene. Bold (1938) examined liverwort sporophytes; he conducted a light microscopy study of the plastids and presented indirect evidence for the widespread occurrence of chloro- phyll in the sporophyte throughout the liverworts. In the same year, Studhalter (1938) indirectly established the presence of chloro- phyll in the sporophyte of Riella americana in all stages of its ontogeny from the zygote to maturity. There are also numerous reports in earlier literature, reviewed by Bold (1938), in which the presence of chlorophyll in sporophytes has been inferred on the basis of a green pigmentation.