Pollen Morphology and Its Systematic Significance in the Ericaceae (original) (raw)

Chapter 1: GENERAL INTRODUCTION Chapter 2: MATERIALS AND METHODS Chapter 3: POLLEN MORPHOLOGY AND ITS SYSTEMATIC SIGNIFICANCE 20 GENERAL POLLEN MORPHOLOGY OF THE ERICACEAE 20 Table 2-1: Some common pollen terminology. Terms are generally based on Punt et al. (1994). Apocolpium: A region at the pole of a zonocolpate pollen grain delimited by lines connecting the apices of the colpi (Fig. 2-2 A). Colpor(oid)ate: A compound aperture characterized by an ectoaperture, a distinct and/or indistinct endoaperture. Colporoidate: A compound aperture characterized by an ectoaperture, an indistinct endoaperture. Colpororate: A compound aperture characterized by an ectoaperture, a shorter lalongate (equatorially elongate) or lolongate (vertically elongate) endoaperture (Fig. 2-1). Colpus (L or 2f): An elongated aperture with a length/breadth ratio greater than 2 (Fig. 2-1). Colpus membrane: The aperture membrane of a colpus (Fig. 2-2 B). Costa (pl. costae): A thickening of the nexine/endexine bordering an endoaperture, or following the outline of an ectoaperture (Fig. 2-2 C). Decussate tetrad: A multiplanar tetrad of pollen grains arranged in two pairs lying across one another, the pairs (dyads) more or less at right angles to each other. Ectexine: The outer part of the exine, which stains positively with basic fuchsin in optical microscopy and has lower electron density TEM sections (Fig. 2-2 D). Endexine: The inner part of the exine which remains relatively unstained with basic fuchsin in optical microscopy and has a higher electron density TEM sections (Fig. 2-2 D). Endocrack: An irregular groove occurring in the inner surface of the nexine/endexine and readily apparent in acetolysed pollen (Fig. 2-2 E). Equatorial diameter (E or d): A line, lying in the equatorial plane, perpendicular to the polar axis and passing through it (Fig. 2-1). Exine: The outer layer of the wall of pollen, which is highly resistant to strong acids and bases, and is composed primarily of sporopollenin (Fig. 2-1). Heterodynamosporus tetrad (pseudomonad): All four pollen grains of the tetrad not of same size (Fig. 2-2 F). Intine: The innermost of the major layers of the pollen grain wall underlying the exine and bordering the surface of the cytoplasm. Isodynamosporus tetrad: All four pollen grains of the tetrad of same size (Fig. 2-2 G). Mesocolpium: The area of a pollen grain surface delimited by lines between the apices of adjacent colpi or the margins of adjacent pores (Fig. 2-2 H).