The Influence of Cadmium, Microplastics, and Their Combination on the Growth and Photosynthetic Characteristics of Kandelia obovata

doi:10.7525/j.issn.1673-5102.2025.04.012

Abstract

Abstract:

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^-1） 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 Kandelia obovata. The aims were to explore the influence of Cd， MPs， and their combination on the growth and photosynthetic characteristics of K. obovata. The results showed that （1）the impact of PE-MPs on the growth of K. obovata was not significant. Under high Cd stress（50 mg⋅kg^-1）， PVC-L significantly restricted the growth of roots and leaves（P<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 P_n， stomatal conductance G_s， transpiration rate T_r， actual photochemical quantum yield（Y（Ⅱ））， electron transfer rate（E_TR）， photochemical quenching coefficient（q_P） and the proportion used for photochemical dissipation（P） of K. obovata leaves（P<0.05）， indicating that PVC-S can alleviate the toxic effects of Cd stress on the photosynthesis of K. obovata. Compared to Cd stress alone， the combined stress of Cd and PE showed no significant effects on chlorophyll fluorescence parameters of K. obovata. Overall， PE and its combined stress with Cd showed no significant effects on the growth and photosynthesis of K. obovata； 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.

Key words: Kandelia obovata, heavy metal, microplastics, plant growth

CLC Number:

Q949.761.7

Minwei CHAI, Yifan WU, Ruili LI, Lin ZHOU, Xiaoxue SHEN. The Influence of Cadmium, Microplastics, and Their Combination on the Growth and Photosynthetic Characteristics of Kandelia obovata[J]. Bulletin of Botanical Research, 2025, 45(4): 603-613.

Figures/Tables 7

Table 1

Fig.1

Fig.2

Table 2

Table 3

Fig.3

Table 4

Characteristics of leaf fluorescence parameters of Kandelia obovata exposed to combined cadmium and microplastics stresses

组别 Group	最大光化学量子产量F_v/F_m	实际光化学量子产量Y（Ⅱ）	电子传递速率E_TR	光化学淬灭系数q_P	非光化学淬灭系数N_PQ	PSⅡ调节性能量耗散的量子产量 Y（N_PQ）	PSⅡ非调节性能量耗散的量子产量Y（N_PQ）	光化学耗散的相对份额P	非光化学耗散的相对份额E_x	天线热耗散份额D
Cd0N-MPs	0.813±0.037^a	0.67±0.02^a	38.75±1.20^a	0.911±0.029^a	0.20±0.04^a	0.06±0.01^a	0.27±0.01^a	0.67±0.02^a	0.066±0.021^c	0.260±0.008^b
Cd0PE-L	0.811±0.011^a	0.64±0.03^ab	36.66±1.42^ab	0.880±0.035^ab	0.26±0.13^a	0.07±0.03^a	0.29±0.01^a	0.64±0.03^ab	0.087±0.025^bc	0.276±0.001^ab
Cd0PE-S	0.813±0.009^a	0.60±0.02^bc	34.74±0.95^bc	0.854±0.008^bc	0.37±0.10^a	0.11±0.03^a	0.29±0.01^a	0.60±0.02^bc	0.103±0.009^ab	0.293±0.025^a
Cd0PVC-L	—	—	—	—	—	—	—	—	—	—
Cd0PVC-S	0.811±0.002^a	0.59±0.02^c	33.63±1.25^c	0.816±0.028^c	0.30±0.05^a	0.10±0.01^a	0.32±0.02^a	0.59±0.02^c	0.132±0.020^a	0.283±0.004^ab
Cd5N-MPs	0.807±0.006^ab	0.56±0.02^a	31.99±1.15^a	0.814±0.024^a	0.42±0.04^a	0.13±0.01^a	0.31±0.02^a	0.56±0.02^a	0.127±0.016^a	0.317±0.005^a
Cd5PE-L	0.799±0.006^b	0.57±0.01^a	32.80±0.58^a	0.838±0.011^a	0.42±0.04^a	0.13±0.01^a	0.30±0.01^a	0.57±0.01^a	0.110±0.007^a	0.320±0.003^a
Cd5PE-S	0.809±0.003^a	0.62±0.04^a	35.44±2.29^a	0.855±0.044^a	0.27±0.09^a	0.08±0.03^a	0.30±0.01^a	0.62±0.04^a	0.104±0.031^a	0.280±0.018^b
Cd5PVC-L	—	—	—	—	—	—	—	—	—	—
Cd5PVC-S	0.804±0.009^ab	0.58±0.02^a	33.02±0.90^a	0.836±0.017^a	0.39±0.07^a	0.12±0.02^a	0.31±0.02^a	0.57±0.02^a	0.113±0.009^a	0.310±0.021^a
Cd50N-MPs	0.782±0.005^ab	0.44±0.02^c	25.40±1.31^c	0.763±0.029^ab	1.08±0.13^a	0.29±0.01^a	0.27±0.02^a	0.44±0.02^c	0.137±0.016^bc	0.422±0.012^a
Cd50PE-L	0.795±0.003^ab	0.48±0.01^b	27.34±0.53^b	0.768±0.004^b	0.80±0.07^a	0.23±0.01^b	0.29±0.01^a	0.48±0.01^b	0.143±0.004^ab	0.381±0.012^b
Cd50PE-S	0.777±0.019^b	0.47±0.01^b	27.13±0.67^b	0.755±0.009^b	0.67±0.29^ab	0.21±0.06^bc	0.32±0.06^a	0.47±0.01^b	0.153±0.006^a	0.376±0.012^b
Cd50PVC-L	—	—	—	—	—	—	—	—	—	—
Cd50PVC-S	0.804±0.003^a	0.56±0.02^a	31.92±1.24^a	0.825±0.009^a	0.47±0.05^b	0.14±0.01^c	0.30±0.02^a	0.56±0.02^a	0.118±0.003^c	0.327±0.020^c

Table 4

References 43

[1]	SHI C， YU L Y， CHAI M W，et al.The distribution and risk of mercury in Shenzhen mangroves，representative urban mangroves affected by human activities in China［J］.Marine Pollution Bulletin，2020，151：110866.
[2]	RAHMAN S U， HAN J C， ZHOU Y，et al.Adaptation and remediation strategies of mangroves against heavy metal contamination in global coastal ecosystems：a review［J］.Journal of Cleaner Production，2024，441：140868.
[3]	CHEN Z L， LEE S Y.Contribution of microplastics to carbon storage in coastal wetland sediments［J］.Environmental Science & Technology Letters，2021，8（12）：1045-1050.
[4]	RICO A， REDONDO-HASSELERHARM P E， SCHELL T，et al.Microplastic burial potential and ecological risks in mangrove forests of the Amazon River delta［J］.Science of the Total Environment，2024，957：177666.
[5]	GUO J J， HUANG X P， XIANG L，et al.Source，migration and toxicology of microplastics in soil［J］.Environment International，2020，137：105263.
[6]	刘加强，崔陆，周子振，等.土壤中微塑料：类型、载体效应、迁移行为和潜在风险综述［J］.生态学报，2024，44（9）：3586-3599.
	LIU J Q， CUI L， ZHOU Z Z，et al.Microplastics in soils：a review of types，carrier effects，migration behavior，and potential risks［J］.Acta Ecologica Sinica，2024，44（9）：3586-3599.
[7]	MAI L， HE H， BAO L J，et al.Plastics are an insignificant carrier of riverine organic pollutants to the coastal oceans［J］.Environmental Science & Technology，2020，54（24）：15852-15860.
[8]	DENG J， GUO P Y， ZHANG X Y，et al.Microplastics and accumulated heavy metals in restored mangrove wetland surface sediments at Jinjiang Estuary（Fujian，China）［J］.Marine Pollution Bulletin，2020，159：111482.
[9]	刘倡君，罗专溪，闫钰，等.九龙江口红树林湿地表层沉积物中微塑料赋存特征与重金属的关系［J］.环境科学，2022，43（1）：239-246.
	LIU C J， LUO Z X， YAN Y，et al.Occurrence characteristics of microplastics in mangrove sediments in the Jiulong River estuary and the association with heavy metals［J］.Environmental Science，2022，43（1）：239-246.
[10]	吴萍，张杏锋，高波，等.微塑料对超富集植物少花龙葵Cd累积的影响［J］.环境科学与技术，2022，45（1）：174-181.
	WU P， ZHANG X F， GAO B，et al.Effects of polyethylene on Cd accumulation of hyperaccumulator Solanum photeinocarpum ［J］.Environmental Science & Technology，2022，45（1）：174-181.
[11]	WANG F Y， ZHANG X Q， ZHANG S Q，et al.Effects of co-contamination of microplastics and Cd on plant growth and Cd accumulation［J］.Toxics，2020，8（2）：36.
[12]	ZHANG Z Q， LI Y， QIU T Y，et al.Microplastics addition reduced the toxicity and uptake of cadmium to Brassica chinensis L［J］.Science of the Total Environment，2022，852：158353.
[13]	王泽正，杨亮，李婕，等.微塑料和镉及其复合对水稻种子萌发的影响［J］.农业环境科学学报，2021，40（1）：44-53.
	WANG Z Z， YANG L， LI J，et al.Single and combined effects of microplastics and cadmium on the germination characteristics of rice seeds［J］.Journal of Agro-Environment Science，2021，40（1）：44-53.
[14]	刘沙沙，杨越，吴静华.微（纳）米塑料介导下多环芳烃的毒性效应研究进展［J］.肇庆学院学报，2022，43（2）：61-65.
	LIU S S， YANG Y， WU J H.Toxic effects of polycyclic aromatic hydrocarbons mediated by micro （nano） plastics［J］.Journal of Zhaoqing University，2022，43（2）：61-65.
[15]	WANG B B， WANG P H， ZHAO S B，et al.Combined effects of microplastics and cadmium on the soil-plant system：phytotoxicity，Cd accumulation and microbial activity［J］.Environmental Pollution，2023，333：121960.
[16]	CAO Y X， ZHAO M J， Ma X Y，et al.A critical review on the interactions of microplastics with heavy metals：mechanism and their combined effect on organisms and humans［J］.Science of the Total Environment，2021，788：147620.
[17]	HUANG F Y， CHEN L， YANG X，et al.Unveiling the impacts of microplastics on cadmium transfer in the soil-plant-human system：a review［J］.Journal of Hazardous Materials，2024，477：135221.
[18]	李荣玉，邱国玉，沈小雪，等.镉胁迫下铵态氮对红树植物秋茄（Kandelia obovata）生理生态特征的影响［J］.植物研究，2018，38（5）：653-660.
	LI R Y， QIU G Y， SHEN X X，et al.Effects of ammonium nitrogen on physiological and ecological characteristics of Kandelia obovata under cadmium stress［J］.Bulletin of Botanical Research，2018，38（5）：653-660.
[19]	CHAI M W， LI R L， LI B，et al.Responses of mangrove （Kandelia obovata） growth，photosynthesis，and rhizosphere soil properties to microplastic pollution［J］.Marine Pollution Bulletin，2023，189：114827.
[20]	NACARIO P B，ALFAFARA P A M， CENIZA N A M，et al.Uptake，growth，and oxidative stress responses of Rhizophora mucronata （Poir.in Lam.） propagules exposed to high-density polyethylene microplastics［J］.Marine Pollution Bulletin，2025，212：117569.
[21]	DAI M Y， LU H L， LIU W W，et al.Phosphorus mediation of cadmium stress in two mangrove seedlings Avicennia marina and Kandelia obovata differing in cadmium accumulation［J］.Ecotoxicology and Environmental Safety，2017，139：272-279.
[22]	CHAI M W， LI R L， DING H，et al.Occurrence and contamination of heavy metals in urban mangroves：a case study in Shenzhen，China［J］.Chemosphere，2019，219：165-173.
[23]	FULLER S， GAUTAM A.A procedure for measuring microplastics using pressurized fluid extraction［J］.Environmental Science & Technology，2016，50（11）：5774-5780.
[24]	FEI Y F， HUANG S Y， ZHANG H B，et al.Response of soil enzyme activities and bacterial communities to the accumulation of microplastics in an acid cropped soil［J］.Science of the Total Environment，2020，707：135634.
[25]	郝再彬，苍晶，徐仲.植物生理实验［M］.哈尔滨：哈尔滨工业大学出版社，2004.
	HAO Z B， CANG J， XU Z.Plant physiological experiment［M］.Harbin：Harbin Industrial University Press，2004.
[26]	GENTY B， BRIANTAIS J M， BAKER N R.The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence［J］.Biochimica et Biophysica Acta（BBA）-General Subjects，1989，990（1）：87-92.
[27]	张守仁.叶绿素荧光动力学参数的意义及讨论［J］.植物学通报，1999，16（4）：444-448.
	ZHANG S R.A discussion on chlorophyll fluorescence kinetics parameters and their significance［J］.Chinese Bulletin of Botany，1999，16（4）：444-448
[28]	KLUGHAMMER C， SCHREIBER U.Saturation pulse method for assessment of energy conversion in PSⅠ［J］.PAM Application Notes，2008，1：11-14.
[29]	DEMMIG-ADAMS B， ADAMS W W， BARKER D H，et al.Using chlorophyll fluorescence to assess the fraction of absorbed light allocated to thermal dissipation of excess excitation［J］.Physiologia Plantarum，1996，98（2）：253-264.
[30]	杨杰，李连祯，周倩，等.土壤环境中微塑料污染：来源、过程及风险［J］.土壤学报，2021，58（2）：281-298.
	YANG J， LI L Z， ZHOU Q，et al.Microplastics contamination of soil environment：sources，processes and risks［J］.Acta Pedologica Sinica，2021，58（2）：281-298.
[31]	WANG F Y， ZHANG X Q， ZHANG S Q，et al.Interactions of microplastics and cadmium on plant growth and arbuscular mycorrhizal fungal communities in an agricultural soil［J］.Chemosphere，2020，254：126791.
[32]	陈欣，郭薇，李济之，等.土壤微塑料影响植物生长的因素与机制研究进展［J］.农业环境科学学报，2024，43（3）：488-495.
	CHEN X， GUO W， LI J Z，et al.Research progress on the influencing factors and mechanisms of soil microplastics on plant growth［J］.Journal of Agro-Environment Science，2024，43（3）：488-495.
[33]	URBINA M A， CORREA F， ABURTO F，et al.Adsorption of polyethylene microbeads and physiological effects on hydroponic maize［J］.Science of the Total Environment，2020，741：140216.
[34]	QI Y L， YANG X M， PELAEZ A M，et al.Macro- and micro- plastics in soil-plant system：effects of plastic mulch film residues on wheat （Triticum aestivum） growth［J］.Science of the Total Environment，2018，645：1048-1056.
[35]	JIANG X F， CHEN H， LIAO Y C，et al.Ecotoxicity and genotoxicity of polystyrene microplastics on higher plant Vicia faba ［J］.Environmental Pollution，2019，250：831-838.
[36]	DE SOUZA MACHADO A A， LAU C W， KLOAS W，et al.Microplastics can change soil properties and affect plant performance［J］.Environmental Science & Technology，2019，53（10）：6044-6052.
[37]	JAMES R A， MUNNS R， VON CAEMMERER S，et al.Photosynthetic capacity is related to the cellular and subcellular partitioning of Na⁺，K⁺ and Cl^- in salt-affected barley and durum wheat［J］.Plant，Cell & Environment，2006，29（12）：2185-2197.
[38]	GOGORCENA Y， LARBI A， ANDALUZ S，et al.Effects of cadmium on cork oak（Quercus suber L.） plants grown in hydroponics［J］.Tree Physiology，2011，31（12）：1401-1412.
[39]	李贞霞，李庆飞，李瑞静，等.黄瓜幼苗对微塑料和镉污染的生理响应［J］.农业环境科学学报，2020，39（5）：973-981.
	LI Z X， LI Q F， LI R J，et al.Physiological response of cucumber seedlings to microplastics and cadmium［J］.Journal of Agro-Environment Science，2020，39（5）：973-981.
[40]	WANG J L， LIU W T， WANG X，et al.Assessing stress responses in potherb mustard （Brassica juncea var. multiceps） exposed to a synergy of microplastics and cadmium：insights from physiology，oxidative damage，and metabolomics［J］.Science of the Total Environment，2024，907：167920.
[41]	ZOUARI M， AHMED C BEN， ZORRIG W，et al.Exogenous proline mediates alleviation of cadmium stress by promoting photosynthetic activity，water status and antioxidative enzymes activities of young date palm （Phoenix dactylifera L.）［J］.Ecotoxicology and Environmental Safety，2016，128：100-108.
[42]	YAN Z Z， TAM N F Y.Effects of lead stress on anti-oxidative enzymes and stress-related hormones in seedlings of Excoecaria agallocha Linn［J］.Plant and Soil，2013，367（1/2）：327-338.
[43]	BENAVIDES M P， GALLEGO S M， TOMARO M L.Cadmium toxicity in plants［J］.Brazilian Journal of Plant Physiology，2005，17（1）：21-34.

处理组 Treatment group	处理方式 Treatment method
Cd0N-MPs	不添加MPs和Cd
Cd0PE-L	830 μm PE（5%）
Cd0PE-S	13 μm PE（5%）
Cd0PVC-L	830 μm PVC（5%）
Cd0PVC-S	13 μm PVC（5%）
Cd5N-MPs	Cd（5 mg·kg^-1）
Cd5PE-L	Cd（5 mg·kg^-1）+830 μm PE（5%）
Cd5PE-S	Cd（5 mg·kg^-1）+13 μm PE（5%）
Cd5PVC-L	Cd（5 mg·kg^-1）+830 μm PVC（5%）
Cd5PVC-S	Cd（5 mg·kg^-1）+13 μm PVC（5%）
Cd50N-MPs	Cd（50 mg·kg^-1）
Cd50PE-L	Cd（50 mg·kg^-1）+830 μm PE（5%）
Cd50PE-S	Cd（50 mg·kg^-1）+13 μm PE（5%）
Cd50PVC-L	Cd（50 mg·kg^-1）+830 μm PVC（5%）
Cd50PVC-S	Cd（50 mg·kg^-1）+13 μm PVC（5%）

指标 Indicators	变异来源 Sources
指标 Indicators	PE	Cd	PE×Cd	PVC	Cd	PVC×Cd
根生物量 Root biomass	0.75	1.52	1.17	17.02^**	1.22	1.32
茎生物量 Stem biomass	3.10	2.07	0.02	1.34	16.55^***	0.11
叶生物量 Leaf biomass	0.26	6.72^*	0.27	—	—	—
总生物量 Total biomass	0.72	2.22	0.59	22.62^***	2.75	2.88
根冠比 Root-shoot ratio	0.30	2.27	0.77	2.72	8.68^**	4.47^*
叶Na含量 Leaf Na content	22.77^**	17.60^**	0.40	—	—	—
叶K含量 Leaf K content	3.12	1.23	3.36	—	—	—
叶Ca含量 Leaf Ca content	0.10	13.16^**	1.56	—	—	—
叶Mg含量 Leaf Mg content	0.05	19.05^**	7.28^*	—	—	—
叶叶绿素a含量 Leaf chlorophyll a content	1.21	5.43^*	4.15^*	—	—	—
叶叶绿素b含量 Leaf chlorophyll b content	1.65	4.56^*	3.21	—	—	—
叶类胡萝卜素含量 Leaf carotenoids content	0.30	8.33^**	2.22	—	—	—
叶总叶绿素含量 Leaf total chlorophyll content	1.48	4.99^*	3.94^*	—	—	—
叶净光合速率 Leaf P_n	8.23^**	64.70^***	0.55	—	—	—
叶气孔导度 Leaf G_s	12.43^***	23.57^***	41.79^***	—	—	—
叶蒸腾速率 Leaf T_r	0.34	34.97^***	44.10^***	—	—	—
叶水分利用效率 Leaf E_WU	0.56	132.51^***	103.47^***	—	—	—
叶最大光化学量子产量 Leaf F_v/F_m	0.18	10.65^**	3.11	—	—	—
叶实际光化学量子产量 Leaf Y（Ⅱ）	0.08	79.17^***	5.18^*	—	—	—
叶电子传递速率 Leaf E_TR	0.08	79.17^***	5.18^*	—	—	—
叶光化学淬灭系数 Leaf q_P	0.43	33.04^***	1.25	—	—	—
叶非光化学淬灭系数 Leaf N_PQ	0.62	15.15^***	1.51	—	—	—
叶PSⅡ调节性能量耗散的量子产量 Leaf Y（N_PQ）	0.73	29.24^***	2.46	—	—	—
叶PSⅡ非调节性能量耗散的量子产量 Leaf Y（N_O）	0.72	0.92	0.81	—	—	—
光化学耗散的相对份额 Leaf P	0.08	79.17^***	5.18^*	—	—	—
非光化学耗散的相对份额 Leaf E_x	0.68	15.75^***	0.64	—	—	—
天线热耗散份额Leaf D	2.01	73.90^***	6.02^*	—	—	—

组别 Group	元素质量分数 Element mass fraction/（mg·g^-1）				Na∶K
组别 Group	Na	K	Ca	Mg	Na∶K
Cd0N-MPs	10.60±2.46^a	24.30±1.01^a	11.24±1.45^a	7.63±0.73^a	0.44±0.12^a
Cd0PE-L	6.01±0.90^a	17.99±2.14^b	12.05±1.63^a	7.04±0.82^a	0.34±0.07^a
Cd0PE-S	7.82±1.53^a	12.05±1.17^c	9.27±0.36^a	5.87±0.45^a	0.61±0.09^a
Cd0PVC-L	—	—	—	—	—
Cd0PVC-S	7.00±1.87^a	13.57±2.71^c	9.43±0.41^a	6.18±1.11^a	0.51±0.07^a
Cd5N-MPs	11.08±3.76^a	16.82±1.03^b	9.54±2.04^a	6.41±1.39^a	0.66±0.21^a
Cd5PE-L	11.72±1.51^a	22.23±1.54^a	10.79±3.17^a	6.94±1.29^a	0.53±0.05^a
Cd5PE-S	7.23±2.19^a	22.35±4.20^ab	11.90±0.52^a	8.10±0.35^a	0.34±0.16^a
Cd5PVC-L	—	—	—	—	—
Cd5PVC-S	7.84±0.30^a	19.25±±1.07^ab	9.18±1.53^a	6.45±0.49^a	0.41±0.02^a
Cd50N-MPs	8.58±1.93^b	23.28±1.34^a	10.28±0.98^a	6.56±0.66^a	0.37±0.08^a
Cd50PE-L	14.69±1.55^a	23.57±1.70^a	7.94±2.62^ab	6.28±0.27^a	0.63±0.09^a
Cd50PE-S	11.24±1.10^ab	16.90±5.20^b	6.05±0.45^b	5.31±0.28^b	0.70±0.19^a
Cd50PVC-L	—	—	—	—	—
Cd50PVC-S	8.63±2.51^b	11.96±1.14^b	10.21±1.40^a	7.14±0.50^a	0.70±0.25^a