AUTHOR=Bai Jiankun , Meng Yuchen , Gou Ruikun , Dai Zheng , Zhu Xiaoshan , Lin Guanghui 

TITLE=The linkages between stomatal physiological traits and rapid expansion of exotic mangrove species (Laguncularia racemosa) in new territories

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1136443

DOI=10.3389/fmars.2023.1136443

ISSN=2296-7745

ABSTRACT=The fast-growing exotic mangrove species (Laguncularia racemose) have been widely introduced in new territories such as China to restore mangrove ecosystems. However, the invasiveness, as well as the mechanisms for the rapid expansion after the introduction are still not well studied. Here, we collected the data on leaf stomata straits, gas-exchange parameters, stable isotope ratios, carbon-nitrogen allocation from L.racemosa and the adjacent native mangroves in Hainan Island, China to reveal possible mechanisms for fast expansion of L.racemosa in new territories. We found that the higher stomatal density but smaller stomatal size of L.racemosa leaves increases stomatal conductance and shorten the diffusion path of CO2 hence enhancing photosynthetic rates. Moreover, the higher stomatal density of L.racemosa exerts a significant positive effect on transpiration, which thus accelerated the water transport and nutrient uptake to meet the advanced need for nutrients and water for fast-growing. The evidence from leaf δ13C and carbon-nitrogen allocation further proved that L.racemosa has a lower intrinsic water use efficiency but a higher rate of photosynthesis than native mangrove species. Our results suggest that stomatal morphological and physiological traits could exert a strong influence on rapid growth of L.racemosa compared to the adjacent native mangroves, which provides a new perspective for fast expansion of exotic mangrove species in China. These findings also suggest that L.racemosa has an invasive potential in native mangrove habitats, thereby the mangrove reforestation projects by introducing L.racemosa should be treated with caution.