Study on the Lipid Composition of Chloroplasts of the Tobacco Mutant N. Tabacum Var. Xanthi Exhibiting an Increased Photosystem I Activity

Abstract

Chloroplasts of the sponge parenchyme of whitish-yellow leaf areas of the plastome mutant Nicotiana tabacum var. Xanthi exhibit in comparison to chloroplasts of green leaf tissue of this mutant a 10–12 fold increased photosystem I activity ( 2160–4040 μmoles 0₂ x mg ch1orophy11^-1 x h^-1 in chloroplasts of whitish-ye11ow leaf areas and 220–340 in chloroplasts of green leaf areas). These chloroplasts are a suitable object for comparative lipid and protein studies with chloroplasts of green leaf areas of the same mutant which exhibit photosystem I as well as photosystem II activity and with chloroplasts of yellow-green leaf areas of N. tabacum mutant NC 95 which exhibit only photosystem I reactions (Homann and Schmid, 1967, Schmid, 1967, Bednarz et al., 1988) above all since these chloroplasts can be isolated in aqueous buffer media without the use of structure destroying detergents.