Exogenous proline and glycinebetaine mitigate cadmium stress in two genetically different spring wheat (Triticum aestivum L.) cultivars

A pot experiment (completely randomized design with four replications) was conducted to appraise the role of exogenously applied proline and glycinebetaine in ameliorating the inhibitory effects of cadmium (Cd) in two wheat cultivars, namely Millat-2011 and Punjab-2011. The Cd stress caused a marked decrease in shoot fresh and dry masses, leaf chlorophylls, carotenoids, anthocyanins, and phenolic contents while increase in tissue malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents. Foliar spray of proline and glycinebetaine caused a significant change in growth and physiochemical attributes of two wheat cultivars under Cd stress. Although both proline and glycinebetaine were effective, plants treated with proline had markedly greater shoot and root fresh masses, leaf phenolics, lesser degradation of chlorophylls, and accumulation of MDA and H2O2 contents under Cd stress. Of the two wheat cultivars, Millat-2011 exhibited better tolerance to Cd toxicity in terms of greater leaf phenolics, lesser damage to photosynthetic pigments, and reduced accumulation of MDA and H2O2 contents.