摘要
通过室内水培试验,研究了不同浓度镉处理(0,25,50,100,200μmol/L)对黄瓜幼苗叶片光合及叶绿素荧光特性的影响。结果表明:镉胁迫第4天,净光合速率、气孔导度和蒸腾速率已显著下降,但细胞间隙CO2浓度变化不大;叶绿素相对含量仅在200μmol/L镉胁迫时下降;叶绿素荧光参数Fv/Fm、Yield和ETR变化不大,表明200μmol/L以下镉处理光合下降的主要原因是气孔因素。在胁迫第8天,所有镉处理净光合速率、气孔导度、蒸腾速率进一步下降,细胞间隙CO2浓度上升,叶绿素相对含量和除NPQ外的所有荧光参数也显著下降,表明此时光合下降与非气孔因素如叶绿素相对含量下降和原初光化学反应受到伤害等有关。50μmol/L镉胁迫导致除NPQ外的所有荧光参数出现一低谷值,原因可能与镉胁迫引起的严重Fe缺乏有关。
The effects of different concentrations of cadmium（0,25,50,100,200 μmol/L） on the photosynthesis and chlorophyll fluorescence characteristics of cucumber seedlings were studied with a solution culture.The results showed that net photosynthetic rate（Pn）,stomatal conductance（Gs） and transpiration rate（Tr） greatly decreased but intercellular CO2 concentration（Ci） showed no change at the 4th day of cadmium stress,relative chlorophyll content only decreased at 200 μmol/L cadmium treatment,while major PSII florescence parameters（the maximal photochemical efficiency of PSII Fv/Fm,the actual photochemical efficiency of PSII in the light Yield and electron transport rate ETR） did not change,indicating a stronger stomatal limitation in the decline of photosynthesis for those treatments with cadmium lower than 200 μmol/L.On the 8th day of cadmium,net photosynthetic rate,stomatal conductance and transpiration decreased more sharply with the increase of intercellular CO2 concentration（Ci）,relative chlorophyll content and major fluorescence parameters except NPQ also decreased,implying a stronger nonstomatal limitation such as decreased chlorophyll content and destroyed PSII primary reaction.The lower value of main fluorescence parameters except NPQ at 50 μmol/L cadmium treatment on the 8th day might be related with serious Fe deficiency caused by cadmium stress.
出处
《水土保持研究》
CSCD
北大核心
2011年第5期187-190,196,共5页
Research of Soil and Water Conservation
关键词
镉胁迫
黄瓜幼苗
光合作用
荧光特性
cadmium stress
cucumber seedling
photosynthesis
fluorescence
