Calcium Mitigates Arsenic Toxicity in Rice Seedlings by Reducing Arsenic Uptake and Modulating the Antioxidant Defense and Glyoxalase Systems and Stress Markers

Abstract

The effect of exogenous calcium (Ca) on hydroponically grown rice seedlings was studied under arsenic (As) stress by investigating the antioxidant and glyoxalase systems. Fourteen-day-old rice (Oryza sativa L. cv. BRRI dhan29) seedlings were exposed to 0.5 and 1 mM Na2HAsO4 alone and in combination with 10 mM CaCl2 (Ca) for 5 days. Both levels of As caused growth inhibition, chlorosis, reduced leaf RWC, and increased As accumulation in the rice seedlings. Both doses of As in growth medium induced oxidative stress through overproduction of reactive oxygen species (ROS) by disrupting the antioxidant defense and glyoxalase systems. Exogenous application of Ca along with both levels of As significantly decreased As accumulation and restored plant growth and water loss. Calcium supplementation in the As-exposed rice seedlings reduced ROS production, increased ascorbate (AsA) content, and increased the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT), glutathione peroxidase (GPX), superoxide dismutase (SOD), and the glyoxalase I (Gly I) and glyoxalase II (Gly II) enzymes compared with seedlings exposed to As only. These results suggest that Ca supplementation improves rice seedlings tolerance to As-induced oxidative stress by reducing As uptake, enhancing their antioxidant defense and glyoxalase systems, and also improving growth and physiological condition.

Manganese-induced salt stress tolerance in rice seedlings: regulation of ion homeostasis, antioxidant defense and glyoxalase systems

“…Simultaneous application of Mn with salt stress improved MG detoxification by increasing the activities of Gly I and Gly II. These results are supported by previous studies (Hasanuzzaman et al 2014a;Rahman et al 2015;Nahar et al 2016b) in which up-regulation of Gly I and Gly II increased MG detoxification and increased oxidative stress tolerance.…”

Upregulation of antioxidant and glyoxalase systems mitigates NaCl stress inBrassica junceaby supplementation of zinc and calcium

“…Supplementation of Ca further enhanced the Gly I and Gly II activity and the results corroborates with the findings of Rahman et al (2016). External supplementation of Ca stimulates glyoxalase enzyme activity and reduces MG content (Rahman et al 2015a, Rahman et al 2015b.…”

“…Singla-Pareek et al (2007) reported that overexpression of Gly II gene in rice enhances tolerance to MG and salt stress. Enhanced activities of Gly I and Gly II reduces MG levels under different abiotic stresses (Rahman et al 2015a. Supplementation of Ca further enhanced the Gly I and Gly II activity and the results corroborates with the findings of Rahman et al (2016).…”

β-Aminobutyric Acid Pretreatment Confers Salt Stress Tolerance in Brassica napus L. by Modulating Reactive Oxygen Species Metabolism and Methylglyoxal Detoxification

“…β-aminobutyric acid treatment increased the Gly I and Gly II levels in salt treated rapeseed plants, which induces MG detoxification. However, the glyoxylase system composed of Gly I and Gly II regulates the enhanced production of MG under various environmental stresses including salinity [55,56], drought [20,57,58], toxic metals [59,60] and heat exposure [61,62]. Previously, Reddy and Sopory [63] observed that overexpression of the Gly I gene decreased the endogenous MG and enhanced the tolerance against MG and salt stress.…”