Normalizing development of cultured Triticum aestivum L. embryos. I: Low energy tensions and exogenous ABA

Wheat (Triticum aestivum L.) embryos form in dynamically-regulated ovular environments. Our objectives were to improve development of cultured immature wheat embryos by simulating, in vitro, abscisic acid (ABA) levels and O 2 tensions as found in wheat ovules during zygotic embryogenesis. We characterized from intact wheat kernels embryo respiration, embryo morphology and embryo and endosperm+ABA levels at 13, 19 and 25 d post-anthesis (DPA). Young (13 DPA) embryos were then excised and cultured in vitro, where they were exposed to 0.2 or 2.0 mmol m -3 ±ABA and 2.1, 2.5 or 7.4 mol m -3 (6, 7 and 21%, respectively) gaseous O 2