Influencing Factors And Phenotypic Selection Of Fruit And Seed Production Of Sambucus Chinensis Lindl.(Caprifoliaceae)

Sambucus chinensis Lindl.belongs to Caprifoliaceae,Sambucus Linn.Which has a large number of extrafloral nectaries scattered in a cymose.It is widely distributed and strong adaptability to the environment.As a medicinal plant,the whole body can be used as medicine and has a high value for use.In this study,five populations of Sambucus chinensis were selected from ya'an and wenjiang for a two-year experiment.The experiment mainly focused on its basic morphological characteristics,flowering phenology,the effect of removing the extrafloral nectaries on fruit seed production,the effect of individual size and onset date on fruit seed production,the effect of inflorescences in different positions on seed setting rate in individual plants,and the function of phenotypic selection in different populations were studied.The results show us follows:(1)The floral characteristic of S.chinensis:It produces a large number of flowers(The number of flowers are 2136±1618.33).Inflorescences have a large number of extrafloral nectaries,which secrete a large amount of nectar,and vary significantly in color with the growing season.The plant height was 131.76±25.938(cm),the ground diameter was 1.044±0.1969(cm),and the inflorescence was multiple(up to 7 layers at most).(2)There were significant differences in plant height,ground diameter,onset date,number of flowers,number of fruits,seed set and number of seeds per fruit among the five populations(all P<0.05).(3)The effect of individual size of S.chinensis on fruit and seed production:The plant height of S.chinensis was significantly positively correlated with the number of fruits,that is,the higher the plant height,the more the number of fruits(R~2=0.117,P<0.05),but it was significantly negatively correlated with the seed set(R~2=0.026,P=0.001).Plant height and number of seeds per fruit were not correlated(R~2=0.005,P=0.181).The diameter analysis was a significant positive correlation with the number of fruits(R~2=0.365,P<0.05),and no correlation with seed set(R~2=0.003,P=0.280)and seed number per fruit(R~2=0.004,P=0.201).There was a significant positive correlation between the number of flowers and the number of fruits and seed set(number of fruits:R~2=0.862,P<0.05;seed set:R~2=0.072,P=0.001),that is,the more the number of flowers,the more the number of fruits,The higher the seed set,but not related to the number of seeds per fruit(R~2=0.005,P=0.143).(4)The effect of flowering time on fruit and seed production:The number of fruits of S.chinensis(R~2=0.202,P<0.05),seed set(R~2=0.044,P<0.05)and number of seeds per fruit(R~2=0.024,P=0.002)were significantly negatively correlated with onset date,indicating that the earlier the flowering time,the more the number of fruits,the higher the seed set,and the more seeds per fruit.(5)The effects of the extrafloral nectaries of S.chinensis on plant growth and development and reproductive fitness:The removal of extrafloral nectaries had no significant effect on plant height(P=0.417),ground diameter(P=0.505),onset date(P=0.355),the number of flowers(P=0.221),seeds number of per fruit(P=0.68),but had significant effect on the number of fruits(P=0.04)and seed set(P<0.001).(6)According to the position of flower heads,the inflorescence can be divided into three levels:the early,the middle,and the late,which represent different positions within individuals of S.chinensis.The female reproductive characteristics of different inflorescences in different populations showed similar trends,that is,there was a significant difference in the seed set of different inflorescence positions,and it showed a trend of decreasing from the early to the late(the early highest,follow by the middle,and the late lowest).(7)The phenotypic selection of S.chinensis:When the number of fruits was used as the fitness,the linear selection of plant height,ground diameter,the number of flower and onset date was significantly different among the populations(all P<0.001).Within the population,there is a significant positive direct linear selection effect on the number of flowers,and a direct linear selection effect with a significant negative effect on onset date,and almost no significant direct linear selection effect on plant height and ground diameter.