Microtubule changes during the development of generative cells in Hippeastrum vittatum pollen

Abstract

Summary.The three-dimensional organization of microtubules in generative cells during their development in pollen grains of Hippeastrum vittatum and the dynamic changes that occur were studied by collecting large quantities of fixed and isolated generative cells for immunofluorescence microscopy. The framework configuration and the arrangement pattern of the microtubule organization was investigated. The microtubule framework changed in shape from being spherical at an early stage to being long spindle-shaped at maturity: various transitional forms were observed: ellipsoidal, pear-shaped and short spindle-shaped. The microtubule arrangement making up this framework changed correspondingly from the original network, which was random in distribution, to axially oriented long bundles via an intermediate pattern composed of a mixture of networks with long bundles. However, cells with the same framework configuration might be heterogeneous in microtubule arrangements.

Comparison of flagellated and nonflagellated sperm in plants

“…In Hippeastrum, development of generative cells from spheroidal to elongate also correlated with a change in arrangement of microtubules from a meshwork to parallel microtubule bundles around the nucleus terminating in cell extensions (Zhou and Yang, 1991). In generative cells of Tradescantia, microtubule bundles were transverse to reticulate, while the generative cell was within the pollen grain (Palevitz and Cresti, 1989).…”

Genetic control of generative cell shape by DUO1 in Arabidopsis

“…At mid-bicellular pollen stage, we observed partial elongation of the GC (Figs. 1 d, 4 b–c), like GCs of some other species (Zhou and Yang 1991 ; Niu et al 1999 ; Zee and Ye 2000 ; Kliwer and Dresselhaus 2010 ; Oh et al 2010 ). In summary, the overall pattern of GC body morphogenesis in Arabidopsis follows that of other angiosperms (Fig.…”

“…Generative cell morphology is described mainly from ultrastructural studies and from immunofluorescence labelling of microtubules (MTs) in fixed samples (Sanger and Jackson 1971 ; Palevitz and Cresti 1989 ; Palevitz 1993 ; Zhou and Yang 1991 ; Russell et al 1996 ). This has allowed detailed 3-D reconstruction such as in Rhododendron , which has an elongated GC body of 17 × 3.5 µm length and width extending over 100 µm when coiled cytoplasmic projections (also known as extensions or ‘tails’) of the GC are included (Theunis et al 1985 ).…”