Relative tolerance of different species of Brassica to cadmium toxicity: Coordinated role of antioxidant defense and glyoxalase systems

Abstract

The present study was carried out to examine the metal accumulation and tolerance abilities of three Brassica species (B. napus, B. campestris, and B. juncea) seedlings exposed to two levels of cadmium (Cd) stress (0.25 and 0.5 mM CdCl 2 for three days). Of the Brassica species studied, B. juncea accumulated the highest amount of Cd in a dose-dependent manner, and in every case, the Cd content was higher in the roots than the shoots. Cadmium stress reduced seedlings biomass, leaf relative water content (RWC), and chlorophyll (chl) content, whereas proline (Pro), MDA, and H 2 O 2 content and lipoxygenase (LOX) activity increased in all species. Under Cd stress, ascorbate (AsA) content reduction was lower and glutathione (GSH) content increase was higher in B. juncea compared with other species. Monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), and superoxide dismutase (SOD) activities increased significantly in B. juncea under Cd stress compared with the other species. Catalase (CAT) activity did not decrease in B. juncea due to Cd stress, compared with the other species. Dehydroascorbate reductase (DHAR) activity decreased with both levels of Cd stress in all species except for B. juncea under 0.25 mM CdCl 2 stress. Glyoxalase system components performed better in B. juncea than the other species under Cd stress. Methylglyoxal (MG) increased substantially under both levels of Cd stress, but MG content was lower in B. juncea compared with the others. Considering the antioxidant defense and glyoxalase systems performance B. juncea is relatively tolerant species to Cd toxicity though it accumulated highest Cd.

Comparative Study of Growth, Cadmium Accumulation and Tolerance of Three Chickpea (Cicer arietinum L.) Cultivars

“…Water homeostasis is not only important for the life processes of plants but also the whole living organism on earth. Different environmental abiotic stresses affect the plant tissues by reducing their leaf relative water content [43]. The root is the first site of contact for TM and significantly higher metals content accumulated in them than shoot of the plants, which may be the reason that affected the absorption of water, and in turn, reduce water content in the root [44].…”

Improved physiological defense responses by application of sodium nitroprusside in Isatis cappadocica Desv. under cadmium stress

“…All the plants were grown for 12 days on Hoagland medium and, on Day 13, treatments were applied. The Cd concentrations (100, 200, 400 μM CdCl 2 ) were selected based on previous studies on similar plants of the Brassicaceae family (Ali et al ., 2014, Al Mahmud et al ., 2017, Kapoor et al ., 2019), applied alone and in combination with 200 μM SNP. The following treatments were tested: (1) nutrient solution alone (control); (2) nutrient solution + SNP; (3) 100 μM CdCl 2 ; (4) 100 μM CdCl 2 + SNP; (5) 200 μM CdCl 2 ; (6) 200 μM CdCl 2 + SNP; (7) 400 μM CdCl 2 ; and (8) 400 μM CdCl 2 + SNP.…”

Metabolic profiles in the xylem sap of Brassica juncea exposed to cadmium

“…Due to its unique physiological mechanism and structural characteristics, B. juncea can adapt to environments with high content of heavy metals, as well as enrich Cd, Pb, Zn, Ni, Cu, Cr, Se, and other heavy metals from soil. Compared with other plants, B. juncea has a stronger enrichment ability and tolerance to Cd (Mahmud et al, 2017; Tan et al, 2021). Thus, selecting B. juncea as experimental material for studying the detoxicating and transport mechanism of heavy metals in plants is particularly vital.…”