Abstract
Various media were tested for in vitro germination of pollen grains of radish and Brassica campestris. The basal medium contained 50 mg·liter-1 H3BO3, 100 mg·liter-1 CaCl2 and the pH was adjusted to pH 5.8. Species of pollen grains tested were : radish (Raphanus sativus L.) 'Harumaki Minowase', 'Ryujin Miura', 'Motohashikei Taibyou Minowase', and four of Brassica campestris L. 'Hiroshimana' and 'Santousai' (non-heading chinese cabbage, pekinensis group), 'Mibuna' (japonica group), and Pak-choi 'Chingensai' (chinensis group). The results obtained were as follows ; 1. The basal medium containing 0.43M sucrose yielded the highest germination rate of radish pollen compared to that at 0.29 or 0.58M sucrose. 2. Among the media adjusted between pH 5.8∿12.0, pH 9.0 gave the best pollen germination. 3. Germination rate was improved by using buffer solutions of pH 8.0 and 8.5, such as Taps, Tris, MES, boric acid or phosphoric acid buffer compared to distilled water. Taps and Tris buffers were most effective, followed by boric acid and barbital buffers. 4. Cholic acid, cetylmethyl ammonium bromide and sodium lauryl sulfate promoted pollen germination of radish. 5. Pollen grains of mother plants of the same age grown under 10∿25°C during May∿June, and October∿December had the best germination rate, whereas those obtained between July∿September had the poorest rate.
