MEGAGAMETOPHYTE DEVELOPMENT IN LOTUS CORNICULATUS, L. CONIMBRICENSIS, AND THEIR PROTOPLAST FUSION HYBRID

Abstract

The development of early ovules, megasporogenesis, and megagametogenesis in Lotus corniculatus L. (2n = 4x = 24), L. conimbricensis L. (2n = 2x = 12), and their protoplast fusion hybrid were studied. The protoplast fusion hybrid plant was known to be completely male sterile and appeared female sterile. The objectives of this study were to examine the development of the ovules and megagametophytes of the protoplast fusion hybrid of L. corniculatus × L. conimbricensis and to compare the development of the ovules and megagametophytes of the fusion hybrid with that of the parent types. The normal development of the ovules and megagametophytes of L. corniculatus, L. conimbricensis, and their protoplast fusion hybrid were similar to those of several other species of Fabaceae. Approximately 24% of the protoplast fusion hybrid ovules developed into apparently normal megagametophytes beyond the critical reduction divisions. The abortion of ovules in the protoplast fusion hybrid occurred at any stage of megasporogenesis or megagametogenesis, but most abortions appeared to be due to postmeiotic failures. Evidence that normal‐appearing megagametophytes of the fusion hybrid are capable of being fertilized and forming zygotes is needed.