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First published online July 24, 2003; 10.1104/pp.103.022632 Plant Physiology 133:145-160 (2003) © 2003 American Society of Plant Biologists Communication between the Maternal Testa and the Embryo and/or Endosperm Affect Testa Attributes in Tomato1,[w]Department of Horticulture (A.B.D., D.Z., L.M.A.D., R.R.T., J.A.P., J.W.B., J.C.S.) and Center of Membrane Sciences, Department of Chemistry (J.L.D., D.A.B.), University of Kentucky, Lexington, Kentucky 40546; and Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (A.A.L.)
Two tomato (Lycopersicon esculentum) mutants with dark testae displaying poor germination rate and percentage on both water and 100 µM gibberellin4 + 7 were recovered. The mutants were allelic (black seed1-1; bks1-1 and bks1-2), inherited in Mendelian fashion as a recessive gene residing on chromosome 11. They are not allelic to bs (brown seed) -1, -2, or -4, which impair seed germination and possess dark testae. The bks/bs mutants accumulated dark pigment in the cell layers of the testa above the endothelium, which itself accumulated proanthocyanidins similar to wild type. The poor germination performance of bks mutant seeds was because of impediment of the mutant testae to radicle egress. Imbibition on gibberellin4 + 7 did not ameliorate germination percentage or rate. The toughening of the bks testa and associated poor germination were partially overcome when seeds were not dried before germination or were dried under N2. The seeds of the bks mutant have elevated activity of at least one enzyme responsible for the detoxification of reactive oxygen species. The bks mutant is epistatic to 12 anthocyaninless mutants of tomato. Bio- and physicochemical analysis of the bks testa determined that it accumulated a melanic substance. Inheritance of bks/bs mutations contrasts with that of the anthocyaninless mutants, which are inherited according to the genotype of the maternally derived testa. This suggests that the testa manufactures components before its demise that can maximize testa strength, whereas the endosperm/embryo produces factors that are conveyed to the testa, mitigating this process.
1 This work was supported by the Department of Horticulture (University of Kentucky, Lexington) and by Hatch funds. [w] The online version of this article contains Web-only data. 2 These authors contributed equally to the paper. * Corresponding author; e-mail adownie{at}uky.edu; fax 859-257-7874. Received February 25, 2003; returned for revision April 28, 2003; accepted June 7, 2003. This article has been cited by other articles:
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