Lead tolerance of water hyacinth (Eichhornia crassipes Mart. - Pontederiaceae) as defined by anatomical and physiological traits

Anais da Academia Brasileira de Ciências

Fabricio J. Pereira¹  Evaristo M. De Castro¹  Cynthia De Oliveira¹  MarinÊs F. Pires¹  Marcio P. Pereira¹  Silvio J. Ramos¹  Valdemar Faquin¹ 

关键词: heavy metals;    ecophysiology;    plant anatomy;    macrophytes;    metais pesados;    ecofisiologia;    anatomia vegetal;    macrófitas;   

DOI  :  10.1590/0001-3765201420140079

来源: SciELO

【 摘 要 】

This study aimed at verifying the lead tolerance of water hyacinth and at looking at consequent anatomical and physiological modifications. Water hyacinth plants were grown on nutrient solutions with five different lead concentrations: 0.00, 0.50, 1.00, 2.00 and 4.00 mg L–1 by 20 days. Photosynthesis, transpiration, stomatal conductance and the Ci/Ca rate were measured at the end of 15 days of experiment. At the end of the experiment, the anatomical modifications in the roots and leaves, and the activity of antioxidant system enzymes, were evaluated. Photosynthetic and Ci/Ca rates were both increased under all lead treatments. Leaf anatomy did not exhibit any evidence of toxicity effects, but showed modifications of the stomata and in the thickness of the palisade and spongy parenchyma in the presence of lead. Likewise, root anatomy did not exhibit any toxicity effects, but the xylem and phloem exhibited favorable modifications as well as increased apoplastic barriers. All antioxidant system enzymes exhibited increased activity in the leaves, and some modifications in roots, in the presence of lead. It is likely, therefore, that water hyacinth tolerance to lead is related to anatomical and physiological modifications such as increased photosynthesis and enhanced anatomical capacity for CO2 assimilation and water conductance.

【 授权许可】

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