Resource allocation among sexual, clonal reproduction and vegetative growth of two Potamogeton species and their hybrid: Adaptability of the hybrid in relation to its parents

Resource allocation, as well as the tradeoffs among different reproductive components, plays an important role in the adaptability of plants to different environments. The hybrid may exhibit a higher adaptability in life history in heterogeneous environments because of the genetic variation derived from its parents. In this study, we exploited three levels of water depths and two types of sediments to investigate the resource allocation pattern of the first generation of the natural hybrid Potamogetonxintortifolius compared to its parents P. wrightii and P. perfoliatus. We also measured the ramet survivorship and the seed set of the hybrid P.xintortifolius. Our results showed that P.xintortifolius had higher ramet survival than its parents at 1.5-m water depth on clay sediment. The possible tradeoffs showed that in P.xintortifolius the tradeoff pattern between sexual and clonal reproduction was more pronounced in limiting environments. The individuals allocated more resources to sexual reproduction when the environment was limiting, which might confer a higher ability to utilize resources, to produce offspring and to found new populations. Although the seed set of P.xintortifolius was lower than its parents, it had a higher ability to increase its seed set when the environment was limiting (sandy sediment) than its parents, which might benefit its future survival. These results indicated that the F-1 hybrid P.xintortifolius was more able to adapt to limiting environments than one or both of its two parental taxa.Resource allocation, as well as the tradeoffs among different reproductive components, plays an important role in the adaptability of plants to different environments. The hybrid may exhibit a higher adaptability in life history in heterogeneous environments because of the genetic variation derived from its parents. In this study, we exploited three levels of water depths and two types of sediments to investigate the resource allocation pattern of the first generation of the natural hybrid Potamogetonxintortifolius compared to its parents P. wrightii and P. perfoliatus. We also measured the ramet survivorship and the seed set of the hybrid P.xintortifolius. Our results showed that P.xintortifolius had higher ramet survival than its parents at 1.5-m water depth on clay sediment. The possible tradeoffs showed that in P.xintortifolius the tradeoff pattern between sexual and clonal reproduction was more pronounced in limiting environments. The individuals allocated more resources to sexual reproduction when the environment was limiting, which might confer a higher ability to utilize resources, to produce offspring and to found new populations. Although the seed set of P.xintortifolius was lower than its parents, it had a higher ability to increase its seed set when the environment was limiting (sandy sediment) than its parents, which might benefit its future survival. These results indicated that the F-1 hybrid P.xintortifolius was more able to adapt to limiting environments than one or both of its two parental taxa