Phenotypic variation in floral traits of an invasive plant (<italic>Solanum rostratum</italic>) and its impact on reproductive fitness

Abstract

<p indent="0mm"><italic>Solanum rostratum</italic> is an invasive plant in China. Our objectives were to determine the phenotypic variations in flowers of <italic>Solanum rostratum</italic> populations and their effect on reproductive fitness. The number of fruits and seeds of 174 individuals and 10 phenotypic traits of 522 flowers were recorded in 6 natural <italic>Solanum rostratum</italic> populations. The results were analyzed using nested analysis of variance, coefficient of variation, correlation analysis, principal component analysis, and multiple regression analysis. Significant differences in phenotypic variations were observed among and within the <italic>Solanum rostratum</italic> populations. The variation was greater among populations (27.26%) than within populations (3.55%). The mean phenotypic differentiation coefficient was 82.31%, indicating that the variance among populations was the main source of the phenotypic variation and that <italic>S</italic>.<italic> rostratum</italic> has a strong ability to adapt to a changing environment. The average coefficient of variation (<italic>CV</italic>) was 13.13%, ranging from 7.45% to 29.79%. The <italic>CV</italic> of the distance between the stigma and the closest feeding stamen (DSF) was the highest, and the <italic>CV</italic> of the length of the pollinating stamen (<italic>LP</italic>) was the lowest. Combined with the results of the principal component analysis, DSF and the distance between the stigma and the pollinating stamen (DSP) were the main directions of phenotypic variation. Longitude had a greater effect on phenotypic variation than altitude, latitude, population size, or density. The floral traits of <italic>Solanum rostratum</italic> had a significant effect on the number of fruits, and the closer the distance between the stigma and the closest feeding stamen, the more fruits were produced.