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A pollen grain undergoes a series of biochemical changes during germination. The technique of cylindrical internal reflectance FTIR was used to examine spectral frequencies associated with respiration, lipid and protein structure, polysaccharide content, and phosphate-containing metabolizes in pollen from pecan, blue spruce, cattail, and pine. Samples of both pollen and germination medium were analyzed at timed intervals. A microscopic evaluation of percent germination was also made at each sampling time. Preliminary analyses indicate that changes in respiration occur as evidenced by the presence of gaseous CO2, and that quantitative changes in lipid and protein occur. FTIR spectroscopy provides a noninvasive method to directly and quantitatively measure metabolic changes associated with pollen germination.
A micropropagation protocol using shoot cultures is described for Lindera melissifolia, a federally listed endangered shrub endemic to the southeastern United States. Stock plants were harvested from native L. melissifolia populations growing in the lower Mississippi Alluvial Valley. In vitro proliferation was on woody plant medium supplemented with 1 μm zeatin. After 6 weeks, zeatin level was increased to 5 μm. Treatment of micropropagated shoots with a liquid auxin (2 indole-3-butyric acid : 1 1-naphthalenacetic acid) resulted in a low mean rooting percentage (≤44%) compared with rooting in the absence of auxins and on a pure peat medium ex vitro, which increased rooting to ≥80%. Time to rooting was 8 weeks. Plants were acclimatized for 2 weeks, then potted in a 2 peat : 1 perlite medium supplemented with superphosphate, 10N–10P–10K, and Milorganite. Micropropagated L. melissifolia stecklings have been successfully outplanted in both controlled and field studies at the Center for Bottomland Hardwoods Research (Stoneville, Miss.).