Low doses of Pb affected Lactuca sativa photosynthetic performance

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• 作者：S. Silva ; G. Pinto ; C. Santos
• 关键词：Additional key wordsabiotic stress ; chlorophyll fluorescence ; gas exchange ; phytotoxicity ; toxic metal
• 刊名：Photosynthetica
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：55
• 期：1
• 页码：50-57
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Physiology;
• 出版者：The Institute of Experimental Biology of the Czech Academy of Sciences
• ISSN：1573-9058
• 卷排序：55

文摘

The effects of soil and water contamination by lead (Pb) and the consequences on plant growth and yield are of great concern worldwide. Limits of the Pb concentration in water have been established by governmental institutions but these differ from each other. In this study, Lactuca sativa (var. Reine de Mai) plants were exposed to low Pb(NO₃)₂ doses (0.05–20 mg L−1), including the recommended limit values for irrigation water by the Food and Agriculture Organization (FAO). After 28 d of exposure, lettuce plants did not present visible morphological alterations or growth impairment, but CO₂ assimilation rate (P_N), photochemical quenching, and effective quantum efficiency of PSII were negatively affected, while intercellular CO₂ concentration, stomatal conductance, or transpiration rate were not influenced. Our results suggested that limitations on photosynthesis occurred from different reasons than due to the decrease of internal CO₂ availability, alterations of photophosphorylation, and/or electron transport rate. Thus, this lettuce cultivar showed photosynthetic susceptibility to low doses of Pb, even at lower concentrations than those maximal allowed for irrigation water by FAO. Furthermore, P_N seemed to be the most sensitive biomarker for evaluation of Pb susceptibility.