Cadmium-induced stress on the seed germination and seedling growth of Brassica napus L., and its alleviation through exogenous plant growth regulators

Abstract

Because of its prolific growth, oilseed rape (Brassica napus L.) can be grown advantageously for phytoremediation of the lands contaminated by industrial wastes. Therefore, toxic effect of cadmium on the germination of oilseed rape, the capability of plants for cadmium phytoextraction, and the effect of exogenous application of plant growth regulators to mitigate phytotoxicity of cadmium were investigated. For the lab study of seedlings at early stage, seeds were grown on filter papers soaked in different solutions of Cd 2? (0, 10, 50, 100, 200 and 400 lM). In greenhouse study, seedlings were grown in soil for 8 weeks, transferred to hydroponic pots for another 6 weeks growth, and then treated with plant growth regulators and cadmium. Four plant growth regulators viz. jasmonic acid (12.5 lM), abscisic acid (10 lM), gibberellin (50 lM) and salicylic acid (50 lM); and three levels of Cd 2? (0, 50 and 100 lM) were applied. Data indicated that lower concentration of Cd 2? (10 lM) promoted the root growth, whereas the severe stresses (200 or 400 lM) had negative effect on the establishment of germinating seedlings. Plants treated with any of the tested plant growth regulators alleviated cadmium toxicity symptoms, which were reflected by more fresh weight, less malondialdehyde concentration in leaves and lower antioxidant enzyme activities. The application of abscisic acid to the plants cultivated in the medium containing 100 lM Cd 2? resulted in significantly lower plant internal cadmium accumulation.

Effects of Cadmium Stress on Alternative Oxidase and Photosystem II in Three Wheat Cultivars

“…Correspondingly, the CY12 cultivar suffered more severe damages than CM42 or CM47. This result conforms to previous studies that excess of Cd in nutrient solution can cause iron defi ciency and decrease plant fresh weight (PerfusBarbeoch et al, 2002;Meng et al, 2009). Likewise, water contents and chlorophyll levels of leaves were higher in CM42 and CM47 than in CY12, though decreased in all three cultivars after Cd stress, implying different cadmium absorption and translocation mechanisms in different cultivars.…”

“…Plants can accumulate Cd during plant growth, and Cd has numerous negative effects on plant cells, such as membrane distortion, changes in nitrogen metabolism, disturbance of water status, production of toxic metabolites and reactive oxygen species (ROS) (Perfus-Barbeoch et al, 2002;Krantev et al, 2008;Meng et al, 2009). Furthermore, it has been noticed that Cd accumulates mainly in roots but not in leaves (Tiryakioglu et al, 2006).…”

Detection of physiological and genotoxic damages reflecting toxicity in Kalanchoe clones

“…The data reveals that the accumulation of Cd was mainly seen in all parts of the plant and was progressive when increasing amount of exogenous Cd was applied. Different application levels of Cd (up to 800 µM) were used in researches related with Cd toxicity (Yang et al, 2004;Nedjimi and Daoud, 2009;Goncalves et al, 2009;Meng et al, 2009). By previous studies performed by Wagner (1993), and Sanita di Toppi and Gabrielli (1999), Cd concentrations (in mM) were found to be between 0.04-0.32 in unpolluted and 0.32-1 in moderate level of polluted soils, respectively.…”

Role of jasmonic acid in improving tolerance of rapeseed (Brassica napus L.) to Cd toxicity

“…In China, especially in the Zhejiang Province, rapeseed and rice are grown in rotation. Irrigation with contaminated water greatly pollutes the fields with heavy metals, especially Cd, that affect crops and pose serious threats to human health (Meng et al, 2009). Cd is one of the most toxic elements worldwide and has the highest pollution index in China (Niu et al, 2013).…”