Gamete Selection In Liriodendron: Anatomic Evidence During Pollen Germination And Tube Growth

Gamete selection is common in most plants, and plays a very important role in plant mating system. In this paper, the gamete selection mechanism of Liriodendron was explored based on cytology evidence. 6 adult trees (3 from L. chinense and 3 from L. tulipifera) were chosen as mating parents according to earlier results of reproductive fitness in Liriodendron. For each mother tree, polles from two father trees that had significant difference in male reproductive fitness were mixed in same quantity and dyed with different component of Pyronin B fluorescence, then pollinated to the mother tree. Afterwards, the differences between two kinds of pollen were compared during pollen germination and pollen tube growth, thus, the gamete selection mechanism was deduced. The main results are as follows.The pollen viability of Liriodendron in recent 3 years was investigated. For pollen viability, no significant difference was existed between 2 species and among parents within species in Liriodendron, while significant difference was existed in 3 years. Pollens of Liriodendron could be stored at 4℃condition for only two days.The pollen fluorescence dye system of Liriodendron was also optimized, that is: PH = 8.01, 50 ppm fluorescence dying liquor, staining time 10min.Based on the observation during pollen germination and pollen tube prolonged, it could conclude that interspecies pollen competition is obvious in Liriodendron. Both L. Chinense and L. tulipifera tends to mate with intra-species gametes. During the growth of pollen tube, those lag pollen tube could not get the nutrition supply, thus lost its reproductive opportunity.This paper provided a brand new idea and method for the field of gamete selection and the male reproduction fitness. It also provided evidence for the Gamete Selective mechanism of Liriodendron.