The Effect Of Different Pollen Sources On The Reproductive Success Of Aconitum Gymnandrum Maxim.

Plants rely on pollinators to pollinate,and produce seeds eventually.In this process,a plant may accepted its own pollen and others to mate.For example,self-pollination(pollen from the same flower)and geitonogamy(pollen from other flowers in the inflorescence),or cross pollen from other individuals of the same species,i.e.cross-pollination.The recognition of conspecific pollen by plants is determined by the self-incompatibility.Selfing can provide reproductive security,but also bring inbreeding depression.At the same time,flowering time has an important effect on the mating and reproductive success of plants,such as the position effect in inflorescence.In addition,Plants share pollinators may lead to pollen transfer,and the transfer of heterospecific pollen may have negative effects on plants.In this study,choosing the protandrous plant A.gymnandrum as the research material.Through field observation and hand-pollination experiments to answer the three questions:(1)whether the visiting behavior of the pollinators of A.gymnandrum in the natural population caused geitonogamy of the same plant,and whether affect the pollen number of stigmas and seed production.(2)whether the geitonogamy affects the reproduction of A.gymnandrum,and the degree of self-incompatibility and inbreeding depression.(3)the effect of heterospecific pollen on the reproductive success of A.gymnandrum.The results showed that:1)The pollination frequency of bumblebee in the same plant from top to bottom and random visiting accounted for 7.75%,so there was geitonogamy of the same plant.The amount of pollen at the base was significantly higher than that at the top,indicating that the pollination behavior of bumblebee could affect the pollen deposition at different positions of inflorescence.There was no significant difference in ovule fertilization rate,seed set and seed maturity rate between different positions.The seed weight and fruit weight at the base were significantly higher than those at the top,indicating that the seed weight had a position effect on the resources utilization.2)After cross-pollination,mixed pollination(self-pollen + cross-pollen),selfcross-pollination and self-pollination.The pollen germination rate of crosspollination is significantly higher than other pollinations,that suggest the pre-zygotic self-incompatibility inhibited the pollen germination and pollen tube growth of self-pollen.At the post-zygote stage,there was no significant difference in ovule fertilization rate,indicating that the expression of post-zygote late selfincompatibility were not significant.The seed set,seed maturity rate,seed weight,fruit weight and seed emergence rate between the four pollination treatments have no significant,indicating that the early inbreeding depression were not significant.When considered the flowering time in the inflorescence,the pollen germination rate of base flowers significantly lower than the top under self-cross-pollination and self-pollination,it shows that the early flowers present stronger self-incompatibility and tend to outcross.There were no significant differences in ovule fertilization rate,seed set,seed maturity rate,seed weight,fruit weight and seed emergence rate at the seeding and seedling emergence stage,indicating that the expression of post-zygote late self-incompatibility and early inbreeding depression were not significant,which had no significant influence on the success of seed reproduction.3)Heterospecific pollen-pollination(Pedicularis kansuensis Maxim.)experiment showed that,the pollen germination rate of 1/2 heterospecific pollen-pollination was significantly lower than conspecific pollen-pollination,There was no significant difference in pollen germination rate between others treatment groups,it showed that heterospecific pollen had a negative effect to pollen germination.The ovule fertilization rate,seed maturity rate and seed weight of two heterospecific pollen-pollination were significantly lower than conspecific pollen-pollination.The fruit weight of 1/2 heterospecific pollen-pollination was also significantly lower than conspecific pollen-pollination.Which showed that the heterospecific pollen had a negative effect on the seed reproductive success of A.gymnandrum.