EMBRYO DEVELOPMENT OF BORAGO OFFICINALIS

Borage seed contains several long-chain fatty acids with -linolenic acid (GLA), a minor fatty acid of medicinal importance, as a major constituent. Seed development was complete about 20 days after pollination (DAP). Meiosis occurred 9 days before anthesis. The 4-cell stage, early heart-shape stage, cotyledon expansion, seed coat darkening, and abscission occurred at 1, 4, 5–16, 16–18, and 17–20 DAP, respectively. Developing borage embryos were analyzed at 2-day intervals, from 6 DAP until mature (18 DAP). Embryo accumulation of fatty acids (6.03 mg) and GLA (0.87 mg) accumulation reached a peak at 16 DAP. Somatic embryos and embryogenic-competent callus initiated from immature zygotic embryos produced GLA. There was a 3.6 fold increase in percent fatty acid and a 1.6 fold increase in percent GLA in cotyledonary somatic embryos relative to embryogenic callus.