Open AccessExclusion of male mitochondria and plastids during syngamy in barley as a basis for maternal inheritance
Author(s) -
Mogensen Hl
Publication year - 1988
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.85.8.2594
Subject(s) - extranuclear inheritance , cytoplasm , biology , sperm , egg cell , embryo , microbiology and biotechnology , vacuole , organelle , non mendelian inheritance , mitochondrion , genetics , plastid , gamete , mitochondrial dna , gene , chloroplast
It is known from genetic analyses that maternal inheritance of cytoplasmic organelles is the rule among plants and animals. Although recognized as one of several possible mechanisms for strictly maternal cytoplasmic inheritance, exclusion of sperm cytoplasm at the time of gametic fusion has remained poorly documented for the flowering plants. In the present investigation, enucleated, cytoplasmic bodies approximately the size of intact, prefusion sperm cells have been observed within degenerated synergids and adjacent to recently fertilized egg cells. A complete series of ultrathin sections (68 sections) through such a cytoplasmic body revealed 59 mitochondria, 3 plastids, 7 dictyosomes, and a large vacuole with no limiting membrane. This structure is interpreted as the entire male cytoplasm that was left outside the egg during fusion between egg and sperm. The observation of only one cytoplasmic body per embryo sac may indicate a preliminary fusion between sperm cells or, more likely, the existence of a fundamentally different mechanism of fertilization between the second sperm and the central cell.