Effects Of Heavy Metals On Physiological And Anatomical Structure Of Invasive And Native Plants Leaves

Industrialization and urbanization of today's modern world cause the environmental contamination of heavy metals.These heavy metals contamination is a widespread problem for human health and plant growth around the world,particularly in developing countries.However,plant species may alter their morphological,physiological,and ecological adaptabilities in response to environmental changes.These responses can be measured through measuring leaf functional traits,among and within species as continuous variation happens around the environment of these traits.Therefore,this study aims to address the effects of separated and combined treatments of Cd and Pb on leaf functional traits.Furthermore,to study the physiological performance and anatomical structure of the invasive and native clonal and non-clonal plants.For experiment ?,we have chosen two pairs of clonal plant species from two genera each from different family with two heavy metal combination: Pb,Cd and Pb+Cd with different concentration Cd 0.20mg/kg,60mg/kg and Pb0.400kg/kg,1200mg/kg respectively.Heterogenic designed were used for this experiment.However,for experiment ? we have chosen twelve plant species from three groups,grasses,legumes and non-legumes.From each group we selected one invasive and one native with the concentration of Cd(80 mg/kg).the study revealed that:1.Under the stress condition of heavy metals,the leaf functional traits of invasive plants were significantly larger than native plants except from LMA(leaf mass per area).These findings indicate that invasive plants with greater leaf functional traits could be able to invade more quickly and capture more resources in a stressful environment.The findings also show that donor clonal ramets can enhance recipient ramets' heavy metal tolerance through clonal integration,which can be beneficial under heterogeneous abiotic stress conditions,such as heavy metals.Ramets in favorable conditions can also be used to develop escape strategies and produce longer stolons in order to move daughter ramets away from unfavorable conditions.These results conclude that invasive plants grow potentially and show satisfactory adaptation to metalliferous conditions than native plants.2.Anatomical properties of invasive and native plant leaves showed gradual changes in treatments samples as compared to control.Heavy metals Cd and Pb disrupted and elevated stomata in all native samples compared with invasive plants which indicated that native plants are much vulnerable to environmental stress and showed direct proportion to heavy metals than invasive plants.Besides this,Potential growth of invasive plants in stressful environments due to thickening of exodermal and endodermal cells,which may suggest adaptation and high tolerance to heavy metals compared to native species.As a result of the heavy metal stress,the morphological structure of epidermal cells and guard cells altered,resulting in an increase in stomatal density whereas a decrease in stomatal width,length and area.Hence,we expected that might be stomatal traits of invasive plants to be potentially good bio-indicators for heavy metals contamination in metalliferous environment.3.The invasive and native plants chlorophyll fluorescence parameters results indicated that Fv/Fm,Fv'/Fm',Ft and F° values decreased with increasing Cd concentration.By contrast?PSII and q P increased at stress conditions of Cd.However,the more decrement of chlorophyll fluorescence parameters was observed in native plants.Therefore,this shows that photosynthetic efficiency of native plants would be decreased,since these elevated levels of Cd have an inhibitory effect on plant physiological and biochemical parameters.4.That the Chl content and NBI values was significantly decreased.By contrast the Flav content significantly increased with high concentration of Cd in both plant species.These results conclude that invasive plants Dualex 4 parameter was less damaged as compared to native plants which shows that invasive plants could hyper accumulator of heavy metals and more resistant to metalliferous environment.We believe that the data presented in this study valuable for the exclusion of heavy metals by using invasive plants through bioremediation or phytoremediation process,and has proved to be effective for the elimination of heavy metals in contaminated soil.