In vitro culture and endogenous hormone levels in immature zygotic embryos, endosperm and callus cultures of normal and high-lysine barley genotypes

Endogenous hormone levels viz. indole-3-acetic acid (IAA), abscisic acid, g ibberellins 1, 3 and 20 (GAs), zeatin/zeatin riboside and N-6(Delta (2)-iso pentenyl) adenine/N-6(Delta (2)-isopentenyl) adenosine were determined in i mmature zygotic embryos and endosperm of the barley (Hordeum vulgare L.) cu ltivar 'Bomi' and its high-lysine mutant 'Riso 1508', 15 days post-anthesis by means of radio immunoassay. Higher levels of IAA and lower levels of GA s were found in embryo and endosperm of 'Bomi', when compared to the corres ponding values in 'Riso 1508'. The same immature zygotic embryos were used as initial explants to establish callus cultures. Non-embryogenic (NE) fria ble callus cultures were obtained in both genotypes; additionally, in culti var 'Bomi', a NE 'compact' callus was also produced, but in lower amounts. No differences in the levels of any of the endogenous hormones analysed cou ld be detected between NE friable callus cultures of both genotypes, while the cytokinin levels varied when compared to the 'compact' cultures. The re sults obtained point to a lack of correlation between the endogenous hormon e levels in the initial explants and the morphogenetic properties of the cu ltures derived from them, at least in this particular case.