The male germ unit in the pollen and pollen tubes ofPetunia hybrida: Ultrastructural,quantitative and three-dimensional features |
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Authors: | V T Wagner H L Mogensen |
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Institution: | (1) Present address: Université Lyon 1-Cl. Bernard, R.C.A.P. bât 741, 43 Boulevard du 11 Nov. 1918, F-69622 Villeurbanne Cedex 02, France;(2) Department of Biological Sciences, Northern Arizona University, Box 5640, 86011 Flagstaff, AZ, USA |
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Abstract: | Summary The male germ unit ofPetunia hybrida was examined quantitatively and qualitatively at the ultrastructutral level. Three-dimensional reconstructions, the determination of nuclear and cytoplasmic volumes and surface areas, and organelle counts were obtained from serial ultrathin sections and computer analysis. In the mature pollen grain, an elongated generative cell is found in direct physical association with and partially surrounded by the vegetative nucleus. The mature generative cell lacks plastids and has mitochondria equally distributed at both of its tapering ends. In the pollen tube, the sperm cells are physically associated by cytoplasmic connections to each other and to the surrounding vegetative cell membrane. At full style length, the lobed vegetative nucleus and sperm pair are found in close association near the end of the pollen tube. The two sperms of a pair are not strongly dimorphic. |
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Keywords: | Generative cell Organelle inheritance Preferential fertilization Sperm dimorphism Vegetative nucleus |
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