Effects of high Zn and Pb concentrations onPhragmites australis(Cav.) Trin. Ex. Steudel: Photosynthetic performance and metal accumulation capacity under controlled conditions

Abstract

The response of Phragmites australis (Cav.) Trin. Ex. Steudel to zinc (Zn) and lead (Pb) was studied separately in two hydroponic tests, during a three weeks experiment. The effects on ecophysiology and biomass partitioning were evaluated during the metal treatments and at the recovery, and total metal content and accumulation capacity in different plant organs were assessed. Zn and Pb had different effects on the overall measured parameters, highlighting different mechanism of action. In particular, Zn concentration was higher in roots and, being a micronutrient, it was translocated into leaves, producing a reduction of assimilation rate, stomatal conductance (-71.9 and -81.3% respect to the control plant respectively), and a strong down regulation of photosystems functionality both at PSII and PSI level. Otherwise, Pb was accumulated mainly in the more lignified tissue such as rhizomes, with slightly effect on gas exchange. Chlorophyll a fluorescence highlighted that Pb inhibits the electron transfer process at the PSI donor side, without recovery after the removal of the metal stress. Despite these physiological limitations, P. australis showed a high capacity to accumulate both metals, and only slight reduction of biomass, being therefore a suitable species for phytoremediation interventions.

Accumulation of Heavy Metal Ions by Eichhornia Crassipes from Battery Industry Effluent under the Influence of Cattle Manure

“…In the present study, metal ions such as Ar, Pb, Ca, Fe and Zn concentration in root were 1.5 times more than shoot. Similar results were obtained for E. Crassipes with 3 to 15 time more concentration in roots [13,18]. Due to industrial effluent, accumulation of various metal ions and external disturbance might affect the accumulation capacity of the plant [10,12,19].…”

“…Root pressure and leaf transpiration are the two-important process controls the translocation of metal ions from root to shoot [16,17]. Due to physiological resistances, plants might not be able to accumulate large amount of metal ions [18]. In the present study, metal ions such as Ar, Pb, Ca, Fe and Zn concentration in root were 1.5 times more than shoot.…”

Assessment of cadmium tolerance and phytoextraction ability in young Populus deltoides L. and Populus × euramericana plants through morpho-anatomical and physiological responses to growth in cadmium enriched soil

“…Plant growth, gas exchange parameters (photosynthetic rate, stomatal conductance, substomatal CO2 concentration), chlorophyll content and chlorophyll a fluorescence parameters are often used as indicators of possible disturbances triggered by heavy metal contamination (Bernardini et al 2016a(Bernardini et al , 2016b. In addition, the rate of photosynthesis has often been correlated with biomass production, and thus might be used as an indicator of the growth potential of tree species and genotypes under pollutant exposure.…”

Gas exchange responses of two poplar clones (Populus euramericana (Dode) Guinier 561/41 and Populus nigra Linnaeus 63/135) to lead toxicity

“…WUE was calculated as the ratio of A to E (Pajević et al 2009). Mesophyll conductance (g m ) was defined as the ratio of A to C i (Bernardini et al 2015). In each poplar clone, the gas exchange measurements were conducted on three replicate plants for each treatment.…”

“…The pollution of soil with heavy metals has become a serious international problem during recent years (Bernardini et al 2015). Lead is not an essential nutrient in plant metabolism, and it is one of the hazardous heavy metal pollutants of the environment originating from various sources, like mining and smelting activities, burning of coal, effluents from storage battery industries, automobile exhausts, pesticides, and from additives to pigments and gasoline, as well as from the disposal of municipal sewage sludge enriched with Pb (Eick et al 1999;Verma, Dubey 2003).…”