Functional Trait Variations in Zizania latifolia: Insights into Climate Adaptation

The global warming could have significant impact on plant adaptation to local environments. Widespread species provides a useful model to examine the population dynamic under climate change. However, it is still unclear how widespread aquatic species response to rapidly changing environments. Wild-rice Zizania latifolia is an emergent macrophyte widely distributed across East Asia. Here, 28 Z. latifolia natural populations covering above 30 latitudes were transplanted in a common garden. The growth, photosynthesis and reproduction traits were quantified and compared among populations, and pairwise relationships among geographic and genetic variables were estimated. Results showed that, in the common garden, the high-latitude populations grew in small size indicating weaker competitiveness in warmer temperatures; the low-latitude populations had no sexual reproduction, suggesting that low-latitude individuals stood little chance to migrate successfully to higher latitude. Significant positive correlations among the distances of genetic, geographic and morphological traits for populations indicated that both isolation by distance and isolation by environment models affected the genetic pattern of populations, and phenotypic traits of Z. latifolia populations might be genetically determined. All our data suggest that Z. latifolia would be inadaptable to the global warming, indicating that this species would be at least at risk of local extinction in the warmer future.