Mutants at Xantha and Albina Loci in Relation to Chloroplast Biogenesis in Barley (Hordeum vulgare L.) 1993. Biologiske Skrifter,42). 115 black&white pls. 20 tabs. figs. 349 p. Lex8vo. Paper bd.

Abstract: Recessive lethal mutants of the xantha and albina phenotypes affecting chloroplast development in barley (Hordeum vulgare L.) have been studied by electron microscopy and spectroscopic analysis of pigments. Nuclear gene loci with functions in differentiation of etioplasts and chloroplasts were identified. Mutants at loci xan-f, -g, -h and alb-e are blocked in protochlorophyllide synthesis and completely blocked mutants fail to form prolamellar body membranes.The loci xan-f, -g, -h and alb-e determine a function in conversion of protoporphyrin IX to Mg protoporphyrin, while locus xan-l is involved in conversion of Mg protoporphyrin to protochlorophyllide. Mutants atloci xan-a, -i, =-k and -u are defective in prolamellar bodymembrane assembly. Mutants at loci xan-j and alb-f are defective inprolamellar body membrane dispersal, lack the 684 to 672 nm spectral shift and are deficient in esterification of chlorophyllide. Mutants atloci xan-m, -o, -p, -q, -s, -t and alb-c and -e are blocked at the two-disc grana stage. Mutants at loci xan-b, -c, -d and -e are blocked late in the assembly of photosynthetic membranes.