COMPARATIVE ANALYSIS OF ULTRASTRUCTURE AND LIPID-COMPOSITION OF PLASTIDS FROM SUN AND SHADE PLANTS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 17  (2) , 442-452
Abstract
Depending on the origin of the plastid, significant differences were observed in the percentage of appressed thylakoids. Accordingly, plastids could be classified into 3 different types: type I chloroplasts, from mesophyll cells of sun plants (barley (Hordeum vulgare), corn (Zea mays), spinach (Spinacia oleracea), bean (Phaseolus vulgaris)), display well-developed grana and intergrana thylakoid membranes. Type II chloroplasts, typical of shade plant (Arum maculatum), show giant grana stacks with few interconnecting thylakoids. Type III chloroplasts, from bundle sheath cells of leaves from C4-plants (corn), are characterized by an extensive development of stroma thylakoids with only occasional rudimentary grana. The percentages of appressed membranes are in the ranges of 50 to 60%, 80% and 2% for type I, II and III plastids, respectively. Striking differences are observed in the fatty acid composition of phosphatidylglycerol molecules. Trans-.DELTA.3-hexadecenoic acid is found only in this phospholipid and amounts to 30 to 40%, 50% and less than 8% of total fatty acids in type I, II and III plastids, respectively. The comparison of ultrastructural and biochemical data suggests a strong correlation between the amounts of phosphatidyl-glycerol molecules containing trans-.DELTA.3-hexadecenoic acid and the percentages of appressed membranes (grana stacks) within plastid stroma.