%0 Journal Article
%A Lin ZHOU
%A Minwei CHAI
%A Ruili LI
%A Xiaoxue SHEN
%A Yifan WU
%T The Influence of Cadmium, Microplastics, and Their Combination on the Growth and Photosynthetic Characteristics of <i>Kandelia obovata</i>
%D 2025
%R 10.7525/j.issn.1673-5102.2025.04.012
%J Bulletin of Botanical Research
%P 603-613
%V 45
%N 4
%X <p>
	Urban mangroves are faced with the environmental problem of combined pollution of heavy metals and microplastics（MPs）. Cadmium（Cd） has a relatively high ecological risk， with polyethylene（PE） and polyvinyl chloride（PVC） to be common microplastic pollutants in mangroves. A combined stress experiment of Cd（0， 5， 50 mg·kg<sup>-1</sup>） and microplastics （small particle size PE-S（13 μm）， large particle size PE-L（830 μm）， small particle size PVC-S（13 μm）， large particle size PVC-L（830 μm）） was carried out for mangrove plant <i>Kandelia obovata</i>. The aims were to explore the influence of Cd， MPs， and their combination on the growth and photosynthetic characteristics of <i>K. obovata</i>. The results showed that （1）the impact of PE-MPs on the growth of <i>K. obovata</i> was not significant. Under high Cd stress（50 mg·kg<sup>-1</sup>）， PVC-L significantly restricted the growth of roots and leaves（<i>P</i>&lt;0.05）. （2）The contents of nutrient elements Na，K，Ca，and Mg in leaves were affected by Cd stress， the types and sizes of MPs. （3）MPs and Cd had synergistic effect on the inhibition of chlorophyll content. The contents of chlorophyll a and carotenoids were the lowest under Cd5PVC-S stress， with the lowest content of chlorophyll b under Cd50PVC-S stress. Under Cd50 stress， PVC-S significantly improved net photosynthetic rate <i>P</i><sub>n</sub>， stomatal conductance <i>G</i><sub>s</sub>， transpiration rate <i>T</i><sub>r</sub>， actual photochemical quantum yield（<i>Y</i>（Ⅱ））， electron transfer rate（<i>E</i><sub>TR</sub>）， photochemical quenching coefficient（<i>q</i><sub>P</sub>） and the proportion used for photochemical dissipation（<i>P</i>） of <i>K. obovata</i> leaves（<i>P</i>&lt;0.05）， indicating that PVC-S can alleviate the toxic effects of Cd stress on the photosynthesis of <i>K. obovata</i>. Compared to Cd stress alone， the combined stress of Cd and PE showed no significant effects on chlorophyll fluorescence parameters of <i>K. obovata</i>. Overall， PE and its combined stress with Cd showed no significant effects on the growth and photosynthesis of <i>K. obovata</i>； PVC had a stronger synergistic effect on Cd stress， with PVC-S alleviating the negative effects of Cd on the photosynthesis， and PVC-L having stronger toxic effect.
</p>
%U https://bbr.nefu.edu.cn/EN/10.7525/j.issn.1673-5102.2025.04.012