Calcium application enhances growth and alleviates the damaging effects induced by Cd stress in sesame (<i>Sesamum indicum</i>L.)

Heavy metal chromium (Cr) is considered to be a serious environmental contaminant due to its toxic effect on living organisms. To mitigate and reduce the negative impacts of Cr in rice plant, the effect of exogenous supplementary calcium was evaluated as it functions as a signaling molecule at cellular level. In this study, growth parameters, protein content, and membrane stability were found to be restored due to calcium under Cr stress. Further, Atomic absorption spectrophotometric analysis revealed that calcium inhibits Cr translocation from root to shoot in rice seedlings. This event was addressed by the enhanced accumulation of phytochelatin that leads to vacuolar sequestration of Cr in roots. Furthermore, increased activity of Catalase, Peroxidase, and Glutathione reductase along with elevated glutathione also assures that calcium enhances antioxidant defense mechanism to cope with Cr toxicity.

Section: Enzymessupporting

confidence: 53%

Calcium induces phytochelatin accumulation to cope with chromium toxicity in rice (Oryza sativaL.)

Mukta

Khatun

2019

“…2 A&B). Increased activity of antioxidant enzymes could be responsible for improved tolerance to Pb-toxicity by protecting membrane functions (Abd_Allah et al, 2017). According to Lu et al (2014), NR induces production of NO that is responsible for the activity of antioxidant enzyme.…”

Section: Discussionmentioning

confidence: 99%

Ascorbic acid improves the tolerance of wheat plants to lead toxicity

Alamri

Siddiqui

Al-Khaishany

et al. 2018

Among the heavy metals (HMs), lead (Pb) is considered as a toxic HM which adversely affects growth and development of crop plants. The present experiment was aimed to investigate the potential role of ascorbic acid (ASC) in the reversal of Pb-inhibited nitrogen and sulfur assimilation enzymes activity and activity of photosynthesis enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and growth response in wheat plants. Wheat seedlings were subjected to 0 mM (control) and 0.2 mM and 0.6 mM of ASC with and without 2 mM of Pb. Plants treated with Pb exhibited the following reduced growth characteristics (root length, shoot length, root fresh weight (FW), shoot FW, root dry weight (DW) and shoot DW). A decrease was also observed in the activity of Rubisco and ATP sulfurylase (ATP-S), relative water content (RWC), accumulation of total chlorophyll (Total Chl) and content of nutrients [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg)] in Pb-treated plants. However, an increase in Chl degradation and in the activity of O-acetylserine(thiol)lyase (OAS-TL) and accumulation of cysteine (Cys), malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) was observed in plants under Pb stress. On the contrary, exogenous application of ASC mitigated the Pb-toxicity-induced oxidative damage by enhancing the activities of antioxidant enzymes, such as superoxide dismutase, catalase and glutathione reductase. Improved activity of antioxidant enzymes suppressed the formation of MDA and H 2 O 2 , which was reflected in the form of improved growth characteristics. Moreover, ASC induced improvement in plants defense systems by reduced Chl degradation and improved the content of essential nutrients (N, P, K, Ca and Mg) and Cys, RWC and the activity of Rubisco, ATP-S, NR and OAS-TL. ARTICLE HISTORY

“…In addition, organic acids such as malate, oxalate, citrate and benzoate have been reported to exhibit the capacity to sequester the metallic cations (Gao et al 2012). Furthermore, calcium was also found to increase the tolerance of plants against stress, to promote growth and development and to enhance protection against heavy metals induced oxidative stress (Wan et al 2011;Ahmad et al 2015;Jan et al 2015;Abd_Allah et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Alleviation of copper toxicity in germinating pea seeds by IAA, GA₃, Ca and citric acid

Massoud

Karmous

Ferjani

et al. 2017

The ameliorating effects of four exogenous effectors were investigated in germinating pea seeds exposed to copper excess. The results showed that the application of IAA, GA 3 , Ca or citric acid alleviated Cu-induced inhibition of growth and simultaneously reduced the oxidative stress injury, particularly contents of hydrogen peroxide, malondialdehyde and carbonyl groups. The improving effects can probably be mediated by the decreases in lipoperoxidation and protein oxidation as evidenced by changes in antioxidant enzyme activities. In addition, the efficiency of this recovery was compared within two types of treatments. Obtained results demonstrated that the stress abruption by the addition of effectors after three days of Cu application (treatment of type II) seems to be more effective than the simultaneous application of 'Cu + effectors' at the beginning of germination (treatment of type I). Data could provide some clues to physiological and biochemical mechanisms of the response of germinating seeds to the addition of chemicals under heavy metal stress.