Improvement of somatic embryogenesis in wild cherry (Prunus avium). Effectof maltose and ABA supplements

Three different types of morphogenesis were identified in embryogenic cultu res of Prunus avium grown on a proliferation medium containing 0.54 mu M NA A, 0.46 mu M kinetin and 0.44 mu M BA: a friable hyperhydric callus, repeti tive embryogenesis and an embryogenic tissue. Translucent and white somatic embryos were produced from the three types of morphogenesis but mainly fro m the embryogenic tissue. These somatic embryos showed histological and cyt ological teratological features such as highly differentiated cells with sh runken cytoplasm and destructured nuclei. For the four lines studied, somat ic embryo production was improved by transferring the embryogenic tissue to developmental media without auxin and cytokinin but supplemented with malt ose alone or maltose and 10 mu M ABA. Three weeks after transfer, the line showing the most embryogenesis produced 1404 somatic embryos per gram of em bryogenic tissue. A concentration of 263 mM maltose significantly increased the number of white somatic embryos for L 10 line, while translucent somat ic embryo production was improved by 88 mM maltose for L 16 line. The combi nation of maltose and ABA produced different effects with each line. When u sed with 88 mM maltose, 10 mu M ABA significantly increased white somatic e mbryo production for two lines but decreased the production for one line. W hen combined with 263 mM maltose, ABA had no effect on white somatic embryo production but significantly decreased the number of translucent somatic e mbryos. Cells of white somatic embryos contained protein storage reserves a nd numerous lipid bodies, while those of translucent embryos did not contai n storage reserves or lipid bodies. After a two-month cold treatment conver sion rate of white and translucent somatic embryos reached 8.5% and 35.2% r espectively.