Chloroplast Ultrastructure of Primary Needles in the Adventitious Shoots of Pinus taeda
Chloroplast ultrastructure of loblolly pine was investigated for the primary needles in 3-month-old and 7-month-old adventitious shoots, for those in the seedlings grown for the same length of the time as those shoots, and for 7-month-old brachyblasts. Two media were used to raise the shoots. For ultrastructural studies samples were fixed in 2% glutaraldehyde in 0.2 M sodium cocadylate, post-fixed in 1% buffered osmium tetroxide, dehydrated through an ethanol series, and embedded in Spurr's resin. Sections were stained with 2% saturated uranyl acetate and Reynold's lead citrate. There were no differences in chloroplast ultrastructure due to media. No fundamental differences were recognized in ultrastructure among mature brachyblasts and the primary needles of 7-month-old seedlings or in vitro adventitious shoots, while the last one showed the least development of grana. Chloroplasts showing irregular arrangement of lamellar system with or without development of grana were dominant in 3-month-old in vitro shoots, while such chloroplasts were rarely seen in the seedlings of the same age.
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Author(s): J. S. Yi, Harry E. Sommer
Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1987