POLLEN TUBE GROWTH AND SEED PRODUCTION IN SELF AND CROSS POLLINATION IN TELOPEA SPECIOSISSIMA

A crossing study and an analysis of pollen tube growth were conducted in Telopea speciosissima to identify mechanisms that may promote the high outcrossing rates observed in this species, and that also result in the absence of viable seed set following self-fertilization.
The crossing study indicated that seed set after self- pollination had reduced fresh weight compared to outcrossed treatments.
Pollen tube growth following hand pollination was assessed in selfed and outcrossed flowers using fluorescence microscopy.
Self-pollinated flowers exhibited far fewer pollen tubes than did the outcrossed flowers.
Only a small number of pollen tubes reached the ovary after self-pollination.
Moreover, survival and germination rates of the seeds from self-pollinated flowers were poor.
Penetration of pollen tubes through the ovular micropyle region was observed 10 days after cross-pollination.
These results indicate that T. speciosissima has a mixed breeding system with preferential outcrossing but is also capable of self-pollination leading to a reduction in seed yield and viability.

VIII International Protea Research Symposium

G.A. Reynoso-Castillo, K. Nomura, S. Fukai, A. Hasegawa, M. Goi

outcrossing, micropyle, fluorescence microscopy, Telopea speciosissima

https://doi.org/10.17660/ActaHortic.2008.805.13