Seed Priming Alters the Production and Detoxification of Reactive Oxygen Intermediates in Rice Seedlings Grown under Sub-optimal Temperature and Nutrient Supply

Abstract

The production and detoxification of reactive oxygen intermediates (ROIs) play an important role in the plant response to nutrient and environmental stresses. The present study demonstrated the behavior of growth, ROIs-production and their detoxification in primed and non-primed rice seedlings under chilling stress (18°C) and nitrogen-(N), phosphorus-(P), or potassium-(K) deprivation. The results revealed that chilling stress as well as deprivation of any mineral nutrient severely hampered the seedling growth of rice, however, seed priming treatments (particularly selenium- or salicylic acid-priming), were effective in enhancing the rice growth under stress conditions. The N-deprivation caused the maximum reduction in shoot growth, while the root growth was only decreased by P- or K-deprivation. Although, N-deprivation enhanced the root length of rice, the root fresh weight was unaffected. Rate of lipid peroxidation as well as the production of ROIs, was generally increased under stress conditions; the K-deprived seedlings recorded significantly lower production of ROIs than N- or P-deprived seedlings. The responses of enzymatic and non-enzymatic antioxidants in rice seedlings to chilling stress were variable with nutrient management regime. All the seed priming were found to trigger or at least maintain the antioxidant defense system of rice seedlings. Notably, the levels of ROIs were significantly reduced by seed priming treatments, which were concomitant with the activities of ROIs-producing enzymes (monoamine oxidase and xanthine oxidase), under all studied conditions. Based on these findings, we put forward the hypothesis that along with role of ROIs-scavenging enzymes, the greater tolerance of primed rice seedlings can also be due to the reduced activity of ROIs-producing enzymes.

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

“…Plants have developed a complex antioxidative defense system, consist of non-enzymatic and enzymatic components to overcome the excessive production of ROS [18,19,42], however, the balance between ROS generation and antioxidant enzyme activities is critical in all plant species under stress conditions [12,43]. Among various anti-oxidants, the SOD involves in the [11,19,36]. In present study, antioxidant enzymes i.e., SOD, POD, CAT, GSH-PX, GR and GST activities were triggered under the drought, chilling and chilling + drought stress conditions (Figure9,10).…”

“…In addition, non-enzymatic antioxidants like GSH, vitamin C (Vc) and vitamin E (V E ) were also been found crucial for stress tolerance in crop plants [11,19]. For instance, the GSH can directly detoxify the O 2•−, •OH, H 2 O 2 and therefore, contributes in stress tolerance in plants [18,42,43,52].…”

“…Previously, Guo et al (2006) stated that the GSH contents were increased under chilling stress but decreased under drought stress in different rice cultivars [20]. Hussain et al (2016b) reported that the Vc and V E are involved in various metabolic processes as non-enzymatic scavenger to quench ROS under stress conditions [19].…”

“…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].…”

Boron supply alleviates Al-induced inhibition of root elongation and physiological characteristics in rapeseed (Brassica napusL.)

“…Corrales et al (2008) reported that B is needed for plants to protect roots from oxidative damage under Al stress by improving defense system. The plants have evolved defense system consisting of both enzymatic as well as non-enzymatic components in order to better handle this elevated oxidative stress (Hussain et al 2016). In the cascade of the enzymatic system, SOD is the first enzyme that transforms damaging free radicals to H 2 O 2 and O 2 , (Noctor and Foyer 1998).…”