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

Abstract

Endogenous hormone levels viz. indole-3-acetic acid (IAA), abscisic acid, gibberellins 1, 3 and 20 (GAs), zcatin/zeatin riboside and N6(Δ2-isopentenyl) adenine/ N6(Δ2-i sopentenyl) adenosine were determined in immature zygotic embryos and endosperm of the barley (Hordeum vulgare L.) cultivar `Bomi' and its high-lysine mutant `Risø 1508', 15 days post-anthesis by means of radio immunoassay. Higher levels of IAA and lower levels of GAs were found in embryo and endosperm of `Bomi', when compared to the corresponding values in `Ricø 1508'. The same immature zygotic embryos were used as initial explants to establish callus cultures. Non-embryogenic (NE) friable callus cultures were obtained in both genotypes; additionally, in cultivar `Bomi', a NE 'compact' callus was also produced, but in lower amounts. No differences in the levels of any of the endogenous hormones analysed could be detected between NE friable callus cultures of both genotypes, while the cytokinin levels varied when compared to the 'compact' cultures. The results obtained point to a lack of correlation between the endogenous hormone levels in the initial explants and the morphogenetic properties of the cultures derived from them, at least in this particular case.