POLLEN-PISTIL INTERACTION IN A NON-PSEUDOGAMOUS APOMICT, COMMIPHORA-WIGHTII

Structural and cytochemical details of the pistil and the interaction of pollen and pistil were studied in a non-pseudogamous apomict, Commi phora wightii. The anthers in the male and bisexual flowers produce Fu nctional pollen grains. The stigma is of the wet and papillate type. T he style is typically solid with two strands of transmitting tissue th at traverse the entire length of the style. There is a marked reductio n in the area occupied by the transmitting tissue From the stigma to t he base of the style. The cells of the transmitting tissue are isodiam etric in transverse as well as longitudinal section and do not form lo ngitudinal files of elongated cells as reported for other taxa. Protei ns could not be localized in the intercellular matrix. Although pollen grains germinate on the stigma; pollen tubes do not grow beyond the p roximal one third of the style. Changed orientation of the cells of th e transmitting tissue and absence of proteins in the intercellular mat rix could account for the failure of the pistil to support pollen grow th. (C) 1998 Annals of Botany Company.