Comparisons between the roles of the fruit tissues, osmoticum and abscisic acid in maintaining tomato seed development and storage protein synthesis

Abstract

AbstractFive distinct groups of storage proteins are synthesized by embryos during development in the fruit at 35 days after pollination (35 DAP); none of them is synthesized in germinating embryos 48 h after isolation (48 HASI) of the seeds from the fruit. Endo-β-mannanase, a marker of germination and seedling growth, is produced in the isolated seeds, but not in the developing seedin situ35 DAP. When seeds at this stage are removed from the fruit, but remain in intimate contact with the locular and sheath tissue, they continue to synthesize storage proteins for at least 48 HASI. Removal of the sheath from seeds isolated 35 DAP stops storage protein synthesis, and increases endo-β-mannanase activity. Both abscisic acid (ABA) and osmoticum at physiological concentrations maintain the synthesis of storage proteins in seeds isolated 35 DAP for at least 48 HASI, although osmoticum is more effective in preventing their eventual germination. Thus the effects of the sheath and the locular tissue are mimicked by both ABA and osmoticum in relation to the maintenance of storage protein synthesis in seeds 35 DAP and in the suppression of endo-β-mannanase activity for at least 48 HASI.