Citric acid assisted phytoremediation of copper by Brassica napus L.

Use of organic acids for promoting heavy metals phytoextraction is gaining worldwide attention. The present study investigated the influence of citric acid (CA) in enhancing copper (Cu) uptake by Brassica napus L. seedlings. 6 Weeks old B. napus seedlings were exposed to different levels of copper (Cu, 0, 50 and 100µM) alone or with CA (2.5mM) in a nutrient medium for 40 days. Exposure to elevated Cu levels (50 and 100µM) significantly reduced the growth, biomass production, chlorophyll content, gas exchange attributes and soluble proteins of B. napus seedlings. In addition, Cu toxicity increased the production of hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) in leaf and root tissues of B. napus. Activities of antioxidant enzymes such as guaiacol peroxidase (POD), superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX) in root and shoot tissues of B. napus were increased in response to lower Cu concentration (50µM) but increased under higher Cu concentration (100µM). Addition of CA into nutrient medium significantly alleviated Cu toxicity effects on B. napus seedlings by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in CA-treated plants seems to play a role in capturing of stress-induced reactive oxygen species as was evident from lower level of H2O2, MDA and EL in CA-treated plants. Increasing Cu concentration in the nutrient medium significantly increased Cu concentration in in B. napus tissues. Cu uptake was further increased by CA application. These results suggested that CA might be a useful strategy for increasing phytoextraction of Cu from contaminated soils.

Zaheer IE ，Ali S ，Rizwan M ，Farid M ，Shakoor MB ，Gill RA ，Najeeb U ，Iqbal N ，Ahmad R ... -  《-》

EDTA enhanced plant growth, antioxidant defense system, and phytoextraction of copper by Brassica napus L.

Habiba U ，Ali S ，Farid M ，Shakoor MB ，Rizwan M ，Ibrahim M ，Abbasi GH ，Hayat T ，Ali B ... -  《-》

Citric acid improves lead (pb) phytoextraction in brassica napus L. by mitigating pb-induced morphological and biochemical damages.

Phytoextraction is an environmentally friendly and a cost-effective strategy for remediation of heavy metal contaminated soils. However, lower bioavailability of some of the metals in polluted environments e.g. lead (Pb) is a major constraint of phytoextraction process that could be overcome by applying organic chelators. We conducted a glasshouse experiment to evaluate the role of citric acid (CA) in enhancing Pb phytoextraction. Brassica napus L. seedlings were grown in hydroponic media and exposed to various treatments of Pb (50 and 100 μM) as alone or in combination with CA (2.5mM) for six weeks. Pb-induced damage in B. napus toxicity was evident from elevated levels of malondialdehyde (MDA) and H2O2 that significantly inhibited plant growth, biomass accumulation, leaf chlorophyll contents and gas exchange parameters. Alternatively, CA application to Pb-stressed B. napus plants arrested lipid membrane damage by limiting MDA and H2O2 production and by improving antioxidant enzyme activities. In addition, CA significantly increased the Pb accumulation in B. napus plants. The study concludes that CA has a potential to improve Pb phytoextraction without damaging plant growth.

Shakoor MB ，Ali S ，Hameed A ，Farid M ，Hussain S ，Yasmeen T ，Najeeb U ，Bharwana SA ，Abbasi GH ... -  《-》

Citric acid enhances the phytoextraction of chromium, plant growth, and photosynthesis by alleviating the oxidative damages in Brassica napus L.

Afshan S ，Ali S ，Bharwana SA ，Rizwan M ，Farid M ，Abbas F ，Ibrahim M ，Mehmood MA ，Abbasi GH ... -  《-》

Synergistic effects of chromium and copper on photosynthetic inhibition, subcellular distribution, and related gene expression in Brassica napus cultivars.

Li L ，Long M ，Islam F ，Farooq MA ，Wang J ，Mwamba TM ，Shou J ，Zhou W ... -  《-》