Differential responses of Myriophyllum alterniflorum DC (Haloragaceae) organs to copper: physiological and developmental approaches

Abstract

International audienceCopper is an essential element for the function of metabolic pathways in many living organisms like photosynthesis in plants. But, for the last decades, anthropogenic sources and release of Cu lead to environmental pollution particularly in aquatic ecosystems. The aquatic plant, Myriophyllum alterniflorum, known as a bioindicator of metal pollution, could be used as biomonitor. The aim of this study is to evaluate biomarkers responses of watermilfoil during Cu pollution at high environmental levels (100 μg l−1 CuSO4) in controlled conditions. Morphological and anatomical features like a new double endodermis (DE) layer were evidenced in response to Cu treatment. Moreover, physiological parameters like pigments contents, osmotic potential and proline content present a differential response to Cu stress in young and old leaves of watermilfoil. Finally, despite a rapid and strong phytoaccumulation of Cu, only young leaves are slightly affected in their cell membrane integrity as indicated by MDA content. In comparison with the Cu effect on other aquatic macrophytes, M. alterniflorum develops particular protection mechanisms like the ROS scavenging using proline rather than carotenoids, the reduction of water loss with the DE and the heavy metal elimination through senescence to protect preferentially the photosynthetic components of the young leaves and the main-stem elongation. Due to its Cu sensitivity, M. alterniflorum appears as important in the field of environmental studies using plant biomarkers

Short-term physiological responses to copper stress in Salvinia auriculata Aubl.

“…This element can be found naturally in water bodies (Delmail et al, 2011) up to a maximum value of 0.009 mg L -1 (≅ 0.141 µM) for freshwater according to Resolution 357/05 of the National Council for the Environment in the Brazil -CONAMA (Brasil, 2005). Though, this metal is between one of the most frequently discharged elements into the environment (Moore, 2011).…”

Antioxidative defense mechanism of the ruderal Verbascum olympicum Boiss. against copper (Cu)-induced stress

“…Previous studies investigating the physiological and antioxidative responses to heavy metal toxicity have generally been on cultivated plants [1,5,39,47]. There are very few studies that investigate Cu-induced stress responses in wild plants.…”

Plant Ageing, a Counteracting Agent to Xenobiotic Stress

“…Among such antioxidants, the most important are the scavengers mainly constituted with -tocopherol (or vitamin E) and carotenoids ( -caroten, xantophylls) (Figs. 2 and 3) (Delmail et al, 2011c(Delmail et al, , 2011d. Considering all these elements, the reactive oxygen species are considered as phytotoxic compounds.…”

“…Reactive oxygen species which initiate the oxidation are produced through several mechanisms in all cell compartments (Delmail et al, 2009;Thompson et al, 1987). Some reactive oxygen species are less deleterious to the plant cell than others but they can act as initiator of the production of more toxic compounds (Delmail et al, 2011c(Delmail et al, , 2011d.…”

“…Indeed, morphological structures as non-glandular trichomes which are not implied in any physiological process, could store many xenobiotics. Moreover, potentially abscised organs as mature leaves are used to eliminate toxics from the living parts to protect the young organs from any disturbance of the photosynthetic pathways (Delmail et al, 2011c(Delmail et al, , 2011d. This chapter will focus on xenobiotics having anthropogenic origins and will address organic and inorganic xenobiotics.…”