Effects of pH, MES, arabinogalactan-proteins on microspore cultures in white cabbage

The objective of this study was to improve induction of embryogenesis in white cabbage (Brassica oleracea var. capitata) microspore cultures. The effect of NLN-13 liquid medium pH on isolated microspore embryogenesis was investigated in five white cabbage genotypes. Relatively high pH (6.2 or 6.4) was more effective on microspore embryogenesis in most of the white cabbage genotypes than the pH of 5.8, especially for inducing microspore-derived embryos in recalcitrant genotype ??Zhonggan No. 8??. Based on this, 2??(N-Morpholino) ethanesulfonic acid (MES) and the arabinogalactan-protein from gum arabic were tested on four out of five genotypes to see if they could increase embryo yield in microspore cultures. Adding MES or gum arabic alone was effective for these four genotypes, but the frequency of embryos derived from microspores was still low. However, the combination of 10?mg?l^?1 gum arabic and 3?mM MES in NLN-13 at pH 6.4 significantly enhanced microspore embryogenesis efficiency (with embryo production of 4.57?C222.97 embryos per bud), especially with recalcitrant genotype ??Zhonggan No. 8?? for which it was increased by about 35-fold.