The cultivation of bulbs for exports in Hokkaido

III. On the pollen tube development and growth of the Easter lily (Lilium longiflorum)

Abstract

1. Influences of temperature and sugar concentration of the germinating bed upon the pollen tube development and growth of the easter lily were investigated.
2. The optimum temperature for the pollen tube development is recognised to be about 30°C and when lowered to 11°C they cannot develop their tubes, in 40°C on the other hand, most of them will burst in a few hours and if some others may germinate their tube growths are almost impossible.
3. The optimum sugar concentration for the pollen tube development is ascertained to be about 8% and though they can germinate freely in a wide range of 2-16% their germinating percentages and tube growths gradually decrease.
4. Pollen tube developments on the stigma are considered to be much the same in both cases of self pollination and cross pollination, but in the former the rapidity of the pollen tube growth in the stylar cavity is a half of the latter for the first 24-40 hours after pollination and when they have travelled down about one half to two thirds of the whole length of the style, most of tubes are arrested decidedly.