外源磷对镉和磺胺甲恶唑复合污染下的香根草生长和光合特性的影响  

Effects of exogenous phosphorus on photosynthetic characteristics of Chrysopogon zizanioides(L.)Roberty under combined cadmium and sulfamethoxazole pollution

作　　者：殷寿延 杨思林[2] 孙仕仙 YIN Shouyan;YANG Silin;SUN Shixian(Yunnan Key Laboratory of Plateau Wetland Conservation,Restoration and Ecological Services,Kunming,Yunnan 650224,China;College of Ecology and Environment(College of Wetlands),Southwest Forestry University,Kunming,Yunnan 650233,China)

机构地区：[1]云南省高原湿地保护修复与生态服务重点实验室,云南昆明650224 [2]西南林业大学生态与环境学院(湿地学院),云南昆明650233

出　　处：《湖南农业大学学报(自然科学版)》2025年第1期51-61,共11页Journal of Hunan Agricultural University(Natural Sciences)

基　　金：国家自然科学基金项目(42167057、41867027);云南省科技计划项目(202201AS070028、202301AS070042、202001AT070117);云南省“万人计划”青年拔尖人才专项(80201442)。

摘　　要：以温室盆栽模拟湿地环境种植香根草,通过添加0.3 mg/kg的镉(Cd)和10 mg/kg的磺胺甲恶唑(SMX)形成复合污染湿地环境,再以60、120、180、240、360 mg/kg的外源磷添加设置5个不同磷水平的Cd-SMX复合污染组(CS1、CS2、CS3、CS4、CS5),以未添加污染物和磷的为对照组(CK),试验持续42 d,分别于试验1、2、3、5、7、14、28、42d时测定香根草地上部和地下部鲜质量、叶绿素质量分数、光合作用参数及叶绿素荧光参数,研究外源磷对Cd-SMX复合污染下的香根草生长和光合特性的影响。结果表明:在试验前期(1~7d时),在外源磷添加和Cd-SMX复合污染下的香根草较CK的呈现一定“毒性兴奋效应”,复合污染促进香根草净光合速率(Pn)和表观光能利用效率(LUE)的提高,而后,因Cd和SMX累积,造成毒性作用,在处理后期,复合污染降低了香根草的光合作用能力,在42 d时,复合污染处理的香根草的PSⅡ实际光化学效率、PSⅡ最大光化学效率(F_(v)/F_(m))、潜在光化学效率(F_(v)/F_(o))、电子传递速率和光化学淬灭系数均显著低于CK的;磷的“生长促进效应”能维持香根草光合作用稳态,香根草叶的P_(n)、F_(v)/F_(m)、F_(v)/F_(o)、表观CO_(2)利用效率和LUE均能在42d时恢复至1 d时水平,其中,42d时CS4的香根草叶Pn为19.55μmol/(m^(2)·s),显著高于其他处理的,同时CS4的香根草茎叶丙二醛含量在复合污染下也最低,为0.93nmol/g。综合来看,在Cd-SMX复合污染的湿地环境下,Cd-SMX复合污染胁迫对香根草光合作用能力造成了一定程度的削弱,而添加240mg/kg的磷能促进香根草地上部茎叶的生长、增强其光合作用能力以抵抗Cd-SMX复合污染的双重胁迫作用。A greenhouse pot experiment simulated wetland conditions to study vetiver grass(Chrysopogon zizanioides(L.)Roberty)growth and photosynthetic responses under cadmium(Cd,0.3 mg/kg)and sulfamethoxazole(SMX,10 mg/kg)composite pollution.Five phosphorus levels(60,120,180,240,and 360 mg/kg)were tested,alongside a control(CK)without pollutants and phosphorus.The experiment lasted 42 days,with measurements taken on days 1,2,3,5,7,14,28,and 42,including the fresh biomass of the aboveground and belowground parts of vetiver grass,chlorophyll content,photosynthetic parameters,and chlorophyll fluorescence parameters.The objective was to investigate the effects of exogenous phosphorus on vetiver grass growth and photosynthetic characteristics under Cd-SMX composite pollution.Early stages(days 1-7)showed a“toxicity stimulation effect”with increased net photosynthetic rate(P_(n))and apparent light use efficiency(LUE)under composite pollution.However,Cd and SMX accumulation later caused toxic effects and reduced photosynthetic capacity,with key parameters including the actual photochemical efficiency of PSII,maximum photochemical efficiency of PSII(F_(v)/F_(m)),potential photochemical efficiency(F_(v)/F_(o)),electron transport rate,and photochemical quenching coefficient,significantly lower than those in the CK on day 42.Phosphorus’s“growth-promoting effect”helped maintain the photosynthetic stability of vetiver grass,with P_(n),F_(v)/F_(m),F_(v)/F_(o),apparent CO_(2) utilization efficiency,and LUE recovering to levels comparable to day 1 by day 42.Notably,P_(n) in the CS4 treatment reached 19.55μmol/(m^(2)·s),significantly higher than in other treatments.Meanwhile,the MDA content in the stems and leaves of vetiver grass under the CS4 treatment was the lowest under composite pollution,measuring 0.93 nmol/g.In summary,Cd-SMX composite pollution weakened vetiver grass’s photosynthetic capacity,but 240 mg/kg phosphorus enhanced its growth of aboveground stems and leaves and photosynthetic resilience,improving tolerance

关 键 词：香根草 外源磷 镉 磺胺甲恶唑 复合污染 富营养化 污染修复 光合特性 

分 类 号：X173[环境科学与工程—环境科学] Q945.11[生物学—植物学]