Improvement of rice (Oryza sativa) germination and seedling growth under cadmium stress conditions using different seed priming agents

Abstract

The non-essential heavy metal cadmium (Cd) prevents rice seed germination and seedling growth when it is present in micromolar concentrations. To mitigate the effects of Cd toxicity on rice, seed priming, a pre-germinated seedling approach, may improve seed and seedling performance. In 2019, an experiment was conducted in Turkey to evaluate seed germination and seedling growth of rice. The experiment was comprised of five concentrations of Cd stress (0, 50, 100, 200 and 400 ppm) on three rice cultivars (Osmancık 97, Halilbey, and Kızıltan) and three seed priming techniques such as hydropriming, priming using 2% KNO3 (potassium nitrate), and priming using 100 mg/L salicylic acid. The complete randomized design was arranged to be conducted with three replications in this investigation. The findings demonstrated that each Cd dose had detrimental effects on seed germination and seedling growth in all rice varieties. All varieties showed different reactions to priming treatments. Hydropriming showed the most positive impact on germination, while priming with KNO3 exhibited negative effects for all rice varieties. The Cd content of plant roots were higher than the shoots. It was observed that the lowest Cd content was detected in the shoots and roots of plants which were pre-treated with SA as compared to other priming applications. More than 50 ppm of cadmium was harmful because it lowered morphological features. However, seed hydropriming partially corrected these effects. For Cd stress resistance, the rice genotype Kızıltan continued to outperform the other cultivars studied.