Pollen Tube Growth in the Pistils Grafted with Style of Different Cultivar or with Cross or Self Pre-pollinated Styles of Lilium longiflorum

The self-incompatibility in Lilium longiflorum was investigated using the differently grafted pistils. Pistils of Lilium longiflorum cv. Georgia and Hinomoto were cut transversely into two parts at 15 or 25mm from stigma tips. They were then grafted in different combinations with silicone rubber tube (2.5mm in inner diameter). Pollen tube growth in the grafted pistils was somewhat reduced as compared with that in the intact style, but the incompatibility responses of the pollen tubes could be studied in the grafted styles.In the pistils grafted with different cultivar, the appearance of self-incompatible responses was observed on the style from the same cultivar. The ovary end portion of the grafted styles seemed to be more influential.In the pistils grafted with cross-pre-pollinated pistil segment, the incompatible pollen tube growth was faster than in the pistils grafted with non- or self-pre-pollinated pistil segments. The necessary condition for the rapid growth of pollen tube was generated in the styles after cross-pollination, with a qrobable velocity of 0.5cm/h from the stigma to the ovary.In self-pre-pollinated pistils, the necessary condition for the rapid growth of pollen tube seemed not to be generated in the style and further any inhibitor for the pollen tube growth was not produced.