AUTHOR=Yang Fan , Zhang Juan , Cisse El-Hadji Malick , Li Da-Dong , Guo Lu-Yao , Xiang Li-Shan , Miao Ling-Feng 

TITLE=Competitive Relationship Between Cleistocalyx operculatus and Syzygium jambos Under Well-Watered Conditions Transforms Into a Mutualistic Relationship Under Waterlogging Stress

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.869418

DOI=10.3389/fpls.2022.869418

ISSN=1664-462X

ABSTRACT=<p>Competition and abiotic stress such as waterlogging (WL) represent main factors limiting plant growth and determining plant resistance and distribution patterns in wetland ecosystems. One of the basic steps for wetland restoration is to plant trees to ensure a quicker recovery and prevent erosion. Plant survival and adaptation are considered criteria of principal priority for the screening of plant species for wetland ecosystem restoration. WL influences plant species in wetlands <italic>via</italic> the deterioration of the plant root environment which leads to oxygen deficiency that affects plant growth, photosynthesis, respiration, and other metabolic processes. A suitable plant species was determined according to tolerance to WL during wetland vegetation recovery activities. Thus, two tree species (<italic>Cleistocalyx operculatus</italic> and <italic>Syzygium jambos</italic>) that showed a certain waterlogging tolerance were chosen to study their behaviors in different planting model and environmental conditions. Given that interspecific relationship should be considered during plant community construction, the eco-physiological adaptable mechanisms between these woody plants under well-watered condition and waterlogging stress were explored. Results showed that both species were waterlogging-tolerant species due to their ability to adapt to submergence conditions for 120 days. Moreover, <italic>C. operculatus</italic> possessed stronger tolerance to waterlogging stress because of a significant adventitious roots biomass accumulation. A competitive relationship was found between <italic>C. operculatus</italic> and <italic>S. jambos</italic> under well-watered condition, and <italic>C. operculatus</italic> showed better growth performance benefited from morphological responses (plant height, number of blade and leaf area) and endogenous hormone variations. In comparison, <italic>S. jambos</italic> suffered some negative effects when the well-watered mixed planting was used. However, the competitive relationship under well-watered condition was transformed into mutualistic relationship under waterlogging stress. The mixed planting under waterlogging condition significantly improved the tolerance of <italic>C. operculatus</italic> and <italic>S. jambos</italic> to waterlogging stress, compared with the monoculture., Especially, <italic>S. jambos</italic> showed improvements in root length, root surface area, and redox equilibration between lower levels of relative conductivity, malondialdehyde, and <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn><mml:mrow><mml:mo>⋅</mml:mo><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula> and had increased levels of non-enzymatic antioxidant components, such as reduced glutathione and soluble proteins. The interspecific relationship between <italic>C. operculatus</italic> and <italic>S. jambos</italic> was altered by waterlogging stress, and both showed improved tolerance to waterlogging stress. This study can provide a glimmer of light on suitable plant species selection and plant community construction during the revegetation activities in wetland zones. <italic>C. operculatus</italic> and <italic>S. jambos</italic> represent potential candidates in wetland restoration in a mixed planting model.</p>