LAUSR

Although environmental factors affecting the adventitious root (AR) have been examined, how nutrient status affects AR under waterlogging conditions remain unclear. In this study, plants' performance in responding to AR regulation based on nutrient supply was investigated in terms of plant morphology, physiology, and AR traits. Results indicated that Cleistocalyx operculatus possesses higher waterlogging tolerance than Syzygium cumini according to the waterlogging tolerance coefficient mainly because of the higher fresh weight, porosity, and length of AR in C. operculatus. Nutrient supply treatment under a waterlogging condition significantly decreased the fresh weight, length, number, porosity, cortex area of AR, and the ratio of cortex to stele area in both species relative to those in the waterlogging treatment but significantly increased the activities and stele areas of AR, and leaf nutrient content. This result showed that nutrient supply caused variations in the morphological and anatomical structures of AR were more beneficial to improve nutrient transportation than oxygen absorption under waterlogging conditions, supporting the nutrient-priority hypothesis. Moreover, nutrient supply under waterlogging conditions induced greater increase in stele area of ARs, fresh weight of a whole plant, total leaf area, leaf nitrogen level, total chlorophyll content, net photosynthesis rate, and maximum photochemical quantum yield of PSII in S. cumini than in C. operculatus, suggesting that S. cumini can transport more nutrients and easily adapts to increase in nutrient supply under waterlogging conditions. Thus, S. cumini have better performance in extracting and utilizing nutrients in the water for plant growth. The findings showed that terrestrial arbor plants have physiological and microstructural mechanisms that respond to nutrient supply under waterlogging conditions and provide novel insights into the phytoremediation of eutrophic water bodies in wetland systems.