5 Conclusion
In the present study, warming exerted mixed effects on the reproductive
pattern of the four populations from different geographic sources.
First, the variation in turion number output was complex among different
populations and the turion biomass production maintained or increased
under warming. Second, warming induced a metamorphosis shift in turions,
as a lower percentage of oligophyllous turions and a higher percentage
of pleophyllous turions generated. Lastly, a complete loss of sexual
reproduction existed under warming. Generally, P. crispus showed
an optimization in reproductive strategy through the adaptive phenotypic
plasticity in reproductive pattern when facing warming scenario. The
geographic distance likely induces local adaptation and the formation of
different ecotypes of P. crispus . Since this mesocosm experiment
used asexual propagules from warm temperate region of China, future
studies should consider different propagule types and a larger scale of
geographic sources for these propagules. Furthermore, a transplant
experiment cross different climate zones may provide a global
perspective in the reproductive strategy of clonal macrophytes and thus
a deeper understanding in its evolutionary implications.