A POSSIBLE ROLE FOR ETHYLENE DURING IAA-INDUCED POLLEN EMBRYOGENESIS IN ANTHER CULTURES OF SOLANUM CAROLINENSE L

Pollen embryogenesis in Solanum carolinense was induced by culturing anthers containing bicellular pollen grains on medium supplemented with indole-3-acetic acid (IAA). Pollen embryogenesis was also promoted by Ethrel and the ethylene precursor, aminocyclopropane carboxylic acid (ACC), although not to the same degree as IAA alone. Furthermore, IAA stimulated ethylene accumulation in culture to the same extent as did Ethrel and ACC. It is suggested that IAA induced pollen embryogenesis at least partially, through auxin-mediated ethylene production. However, since CoCl₂, an inhibitor of ethylene synthesis, reduced the amount of ethylene in IAA-treated cultures but did not eliminate the formation of pollen embryos, IAA also appears to have a direct effect on morphogenesis in anther cultures.