Haemoglobin expression in germinating barley

Polyclonal antibodies to purified recombinant barley haemoglobin (Hb) have been raised in rabbits and used to investigate its expression in monocotyledonous plants. Very little or no Hb expression was observed in dry barley seeds but germination resulted in the expression of Hb which peaked at 2-3 days after imbibition. Hb expression was also observed in maize, wheat, wild oat and Echinochloa crus-galli seeds during germination. Dissection of tissues from the barley seedlings showed that most of the haemoglobin was expressed in the root and seed coat (aleurone layer), with very little in the coleoptile. Imbibition of half-seeds or excised embryos resulted in the expression of haemoglobin. ATP measurements of barley embryos showed that ATP levels quickly increase after imbibition. alpha-Amylase activity was also determined in embryos to correlate Hb expression with a well-characterized germination response. The results demonstrate that Hb expression is a normal consequence of germination.