POLLEN TUBES GROWTH FOLLOWING SELF- AND CROSSPOLLINATION IN Melaleuca alternifolia (Maiden & Betche) Cheel

Pollen tubes growth following controlled self-and croos-polination of several individual of tress of melaleuca alternifolia was observed under fluorescence microscope. Two experiment during 2004 and 2005 flowering season were carried out at M. alternifolia seed orchard at West Wyalong , New South Wales (Australia). Pollen tubes number was investigated at 4 , 7 , 9 and 14 days after pollination by fluorescence microscope. Ovule peneration by pollen tubes was investigated 14 days after pollination. They varied greatly between self-and cross-pollen tubes in the style, with less pollen tube found in the self-pollinated styles than cross-pollinated styles. The mean number of pollen tubes declined significantly as interval to harvesting of the style increased, from a maximum  at the days 4 after pollination. The availability of self-pollen tubes grow in the style of M.alternifolia shows that mechanism of self-incompatibility occurs in this species. The reduction of number of pollen tubes in the lower parts of style shows that the self-incompatibility systems operate in the stigma or the style. The rejection of self-pollen tubes at the ovarian level and the consequent low levels or intolerance of selfing maintains a high level of outcrossing in M.alternifolia.