Physiological and Biochemical Mechanisms of Seed Priming-Induced Chilling Tolerance in Rice Cultivars

Abstract

Rice belongs to tropical and subtropical environments and is extremely sensitive to chilling stress particularly during emergence and early stages of seedling development. Seed priming can be a good approach to enhance rice germination and stand establishment under chilling stress. The present study examined the role of different seed priming techniques viz., hydropriming, osmopriming, redox priming, chemical priming, and hormonal priming, in enhancing the chilling tolerance in rice. The most effective reagents and their pre-optimized concentrations based on preliminary experiments were used in this study. Two different rice cultivars were sown under chilling stress (18°C) and normal temperatures (28°C) in separate growth chambers. A non-primed control treatment was also maintained for comparison. Chilling stress caused erratic and delayed germination, poor seedling growth, reduced starch metabolism, and lower respiration rate, while higher lipid peroxidation and hydrogen peroxide accumulation in rice seedlings of both cultivars. Nevertheless, all the seed priming treatments effectively alleviated the negative effects of chilling stress. In addition, seed priming treatments triggered the activities of superoxide dismutase, peroxidase, and catalase, and enhanced the accumulations of glutathione and free proline in rice seedlings, which suggests that these measures help prevent the rice seedlings from chilling induced oxidative stress. Chemical priming with selenium and hormonal priming with salicylic acid remained more effective treatments for both rice cultivars under chilling stress than all other priming treatments. The better performance and greater tolerance of primed rice seedlings was associated with enhanced starch metabolism, high respiration rate, lower lipid peroxidation, and strong antioxidative defense system under chilling stress.

Effects of low temperature on photosynthetic characteristics in the super-high-yield hybrid rice ‘Liangyoupeijiu’ at the seedling stage

“…ROS are chemically aggressive, and attack the polyunsaturated fatty acid components of membrane lipids, resulting in lipid peroxidation (Shah et al, 2001). This process results in the disruption of the physical and functional properties of membranes (Hussain et al, 2016). In the present study, 'Liangyoupeijiu' had lower levels of lipid peroxidation than the control plants at low temperature, while cold stress resulted in higher lipid peroxidation levels in 'Shanyou63'.…”

Elicitor-Induced Biochemical and Molecular Manifestations to Improve Drought Tolerance in Rice (Oryza sativa L.) through Seed-Priming

“…Seed-priming of wheat with salicylic acid (SA) increased moisture content, dry matter yield, antioxidant activity and total chlorophyll content under drought stress (Singh and Usha, 2003), and selenium (Se) priming was reported to enhance drought tolerance in rapeseed by regulating enzymatic and non-enzymatic antioxidant activities (Hasanuzzaman and Fujita, 2011). Recently, seed-priming with selenium (Se) and SA was reported to be more effective in protecting rice plants against chilling stress (Hussain et al, 2016b). Thus, seed-priming with plant hormone and chemical compound is found to be effective in assuaging the damaging effects of abiotic stress in plants.…”

Individual and concurrent effects of drought and chilling stresses on morpho-physiological characteristics and oxidative metabolism of maize cultivars

“…Furthermore, the growth performance of hybrid maize was better than inbred cultivars under control as well as stress conditions (Figure 1,2 and 3). Early season drought coupled with chilling stress limited seed germination and early stand establishment that may be due to reduced intake of water during seed imbibition [4,18,19,21]. Drought and chilling-induced reductions in morphological traits of maize have also been reported previously [4,9,21].…”

“…Osmo-regulation by accumulation of different osmolytes plays significant role in turgor maintenance and protection of macromolecules in dehydrating cells under stressful conditions [15,16]. In order to control the overproduction of ROS, the plants have a highly efficient and sophisticated enzymatic and non-enzymatic antioxidative defense system [1,18,19]. Guo et al (2006) reported that drought and chilling tolerance in plants is strongly linked with the enhanced activities/levels of antioxidants under stress condition [20].…”