Localization of Phosphorus and Cation Reserves in Lilium longiflorum Pollen

Abstract

Transmission electron microscopy of pollen from Lilium longiflorum Thunb. reveals electron-dense inclusions in storage body organelles ubiquitous in the cytosol. In ungerminated pollen, these inclusions are rounded in appearance and appressed to the inner surface of the smooth membrane of the storage body. During pollen germination, these inclusions become less rounded, smaller, and enclosed in storage bodies that have developed crenated membranes. Energy dispersive x-ray analysis reveals high levels of P, Mg, K, and Ca in the inclusions relative to other regions of the cytosol in which elemental signals can be obtained. The elemental composition and the degradation of inclusions during germination are offered as evidence for storage of phytin in these structures which are thus analogous to phytin storage globoids of seed tissues.

Energy Dispersive X-Ray Analysis

“…1984;Moore etal. 1987;Baldi et al 1987), perhaps because of the difficulty and uncertainties of analysis and the complicating factors (Hall and Gupta 1979) discussed briefly below. Semiquantitative and qualitative data is often adequate.…”

“…The reader is recommended to refer to Zierold and Hagler (1989), Newbury (1988), Bald (1987), Joy (1987), Newbury et al (1986), Morgan (1985), Revel et al (1984), Goldstein et al (1981), and Echlin (1978) who review aspects of the subject and give details of specimen preparation. Journals such as Scanning Microscopy (Scanning Electron Microscopy until 1987), Micron and Microscopia Acta (formerly Micron) and the Journal of Microscopy regularly publish new techniques for EDX analysis.…”

“…Liquid nitrogen can give excellent cryopreservation if the specimen is rapidly plunged into it (Bald 1987). Other widely used plunge coolants are propane (obtained from gas blow-torch cylinders; as it is inflammable, the liquefied gas is a hazard, particularly in basement laboratories) and chlorofluorocarbons (obtained from dust-blowing cans in most EM laboratories).…”

“…If cooling is not rapid, ice crystals will grow within the specimen and physically disrupt the tissue, concentrating ions in the part of the cell or tissue which is frozen last. Vitrifaction of the water in cells, where the freezing occurs so rapidly that no ice crystals form, can be achieved near a specimen surface and in single cells (Bald 1987).…”

“…Cryopreserved and sectioned specimens analyzed in the STEM can give excellent quantitative data on element amounts and locations. Robards (1985) has given a short review of cryopreparation methods, and Bald (1987) has reviewed the subject in depth.…”