Quantitative Observations on the Pattern of Synergid Degeneration in Barley

Serial sections of 75 ovules taken from two pollinations were examined in order to determine the pattern of early synergid degeneration in Hordeum vulgare (Bonus). It was found that synergid degeneration occurs in various patterns in ovules from successful pollinations: either both synergids degenerate, or only one degenerates; in those ovules where only one synergid degenerates, the degenerate synergid is nearly always located either proximal or distal to the placental attachment of the ovule. The results suggest that 1) synergid degeneration depends upon successful pollination, 2) degeneration of both synergids is equally as likely to occur as degeneration of only one synergid, and 3) in those cases where only one synergid degenerates, there is a greater tendency for the degenerate synergid to be located toward the placenta.