Fruit setting rate
Taking into account the man-made and natural damage to the processed inflorescences during the experiment, we selected 20 healthy inflorescences from the harvest samples for fruit-setting statistics (Fig 3).
Through a one-way analysis of variance, it was found that the fruit setting rate was significantly correlated with pollination methods (F=182.2, P<0.01; Figure 3a). Xenogamy (X, 47.0%) can significantly increase the fruit setting rate than natural conditions (OP, 35.8%), while the fruit setting rate under autogamy (SP, 5.7%) and geitonogamy (G, 8.3%) was significantly lower than that under open pollination (OP, 35.8%). The results revealed that V. negundo L. var. heterophylla has self-compatibility and can successfully produce offspring through selfing, but there was inbreeding depression during the seed maturation process.
The anemophily (WP, 0.5%, Fig 3a) was also observed which can produce offspring, although the fruit setting rate was very low. It was clear that V. negundo L. var. heterophylla cannot carry out spontaneously autogamy (SSP, 0%, Fig 3a), and the fruit setting rate under this pollination mode was always 0 and there was no apomixes. Only one of the four ovules of V. negundo L. var. heterophyllacan fully develop and bear fruit, and the fruit setting rate is constantly at 25%.