AUTHOR=Wang Yalin , Chen Xiuwen , Liu Junchu , Hong Yaping , He Qiankun , Yu Dan , Liu Chunhua , Dingshanbayi Huanjiang 

TITLE=Greater Performance of Exotic Elodea nuttallii in Response to Water Level May Make It a Better Invader Than Exotic Egeria densa During Winter and Spring

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00144

DOI=10.3389/fpls.2019.00144

ISSN=1664-462X

ABSTRACT=<p>The strategy of producing rapid initial growth and establishing early in the growing season is important, and it is employed by invasive macrophytes. <italic>Elodea nuttallii</italic> and <italic>Egeria densa</italic>, two Hydrocharitaceae species, became weeds after invading many countries in recent years. Comparative studies on their invasive traits in relation to native species during winter and spring are limited. In the present study, we compared the growth performance of these two exotic species with a perennial native species, <italic>Potamogeton maackianus</italic>, in different water depths (1, 2, and 3 m) during winter (January and February) and spring (March and April). Three morphological traits (shoot number, root number and shoot length), total biomass, relative growth rate (RGR) and two physiological photosynthetic traits (total chlorophyll content and the maximum quantum yield of PSII [<italic>F</italic>v/<italic>F</italic>m]) were measured for each macrophyte. All three species could overwinter as entirely leafy plants. Biomass, RGR, morphological traits and physiological traits were all different among species. However, water depths had a significant effect only on morphological traits. At all water depths, <italic>E. nuttallii</italic> had significantly higher values for morphological traits, total biomass and RGR than <italic>P. maackianus</italic>, while <italic>E. densa</italic> had significantly fewer roots and a lower total chlorophyll content than <italic>P. maackianus</italic>. Except for <italic>F</italic>v/<italic>F</italic>m at a 3 m water depth, morphological and physiological photosynthetic traits, biomass and RGR of <italic>E. nuttallii</italic> were significantly higher than those of <italic>E. densa.</italic> In addition, a large number of adventitious roots developed from <italic>E. nuttallii</italic> but not from the other two species. These results indicate that the advantages of <italic>E. nuttallii</italic> to grow in winter and spring may make it more prone to expansion than <italic>E. densa</italic> in China.</p>