Characterization of Leaf Gas Exchange and Anti-oxidant Defense of Rice (Oryza sativa L.) Cultivars Differing in Submergence Tolerance Owing to Complete Submergence and Consequent Re-aeration

Abstract

The impact of submergence on the photosynthesis and antioxidant capacities in three Indica rice cultivars namely FR 13A, IR 42, and Sabita having differential response to flooding were examined under 8 days (d) of complete submergence and subsequent re-aeration for 24 h. All upon three genotypes showed inhibition of CO 2 photosynthetic rate due to complete submergence; this was accompanied with the decrease in the Rubisco activity, stomatal conductance (g s ), and leaf chlorophyll (Chl) content. These parameters decreased further after 24 h of re-aeration. The decrease was more pronounced in sensitive cultivar, IR 42, and elongating type cultivar, Sabita. Sensitivity of elongating type cultivar under complete submergence was alike to submergence sensitive type cultivar. The activities of antioxidant enzymes such as superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase and levels of ascorbate were found to be significantly high in tolerant cv. FR 13A during submergence and subsequent re-aeration period. This study indicates that the suppression of CO 2 photo-assimilation under submergence was not only due to decrease of g s and leaf chlorophyll content but mainly due to the inhibition of rubisco activity. A greater protection of the photosynthetic system was observed through antioxidant system, since the degree of protection was more, when the levels of ascorbate and the activities of antioxidant enzymes were high.

Exogenous Application of Nitrogen and Cytokinin on Growth, Carbohydrate, and Antioxidant Metabolism of Creeping Bentgrass after De-submergence

“…Antioxidant enzymes play an important role in the removal of toxicity caused by an accumulation of reactive oxygen species under stress conditions. As shown in previous studies, the activities of antioxidant enzymes increased, decreased, and remained unchanged in different plant species, cultivars, and plant tissues under submergence stress (Liu and Jiang, 2015;Panda and Sarkar, 2013;Tan et al, 2010). In rice, submergence increased MDA content (Lal et al, 2015), but the tolerant cultivar had higher antioxidant enzyme activities and chlorophyll content and lower MDA content than that of the intolerant cultivars during submergence (Panda and Sarkar, 2013).…”

“…1). In rice, N application did not cause a significate reduction of SOD and CAT activities after submergence (Gautam et al, 2014a), but the tolerant cultivar had significantly higher SOD, CAT, POD, and APX activities than the intolerant cultivars (Panda and Sarkar, 2013). It seems that the antioxidant responses of plants to N or CK application are varied and complex, depending on species, cultivars, and experimental conditions.…”

Leaf photosynthesis and antioxidant response in selected traditional rice landraces of Jeypore tract of Odisha, India to submergence

“…The adverse effect of submergence on rice varies with cultivars, such as the developmental stage at which flooding occurs, duration and depth, and other hostile environmental parameters (Colmer and Pedersen 2008;Panda et al 2008;Das et al 2009;Afrin et al 2018). Various interrelated factors are also attributed to varying submergence susceptibility such as limited gas diffusion, reduced irradiance, decrease in adenylate energy charge, cytoplasmic acidification and decrease in membrane barrier function, which cause several visible injuries, damage photosynthetic apparatus and impair plant photosynthesis (Drew 1997;Ram et al 2002;Panda et al 2008;Panda and Sarkar 2013;Singh et al 2017). Maintaining normal photosynthetic characteristics during and after submergence is regarded as one of the adaptive strategy of submergence tolerant cultivar (Panda et al 2008;Panda and Sarkar 2013).…”

“…Various interrelated factors are also attributed to varying submergence susceptibility such as limited gas diffusion, reduced irradiance, decrease in adenylate energy charge, cytoplasmic acidification and decrease in membrane barrier function, which cause several visible injuries, damage photosynthetic apparatus and impair plant photosynthesis (Drew 1997;Ram et al 2002;Panda et al 2008;Panda and Sarkar 2013;Singh et al 2017). Maintaining normal photosynthetic characteristics during and after submergence is regarded as one of the adaptive strategy of submergence tolerant cultivar (Panda et al 2008;Panda and Sarkar 2013). Although, significant progress has been made for studying the impact of submergence on photosynthetic mechanism; there is no unified phenomenon available to explain the exact cause of the reduction of photosynthesis in rice.…”

“…(Damanik et al 2010). The tolerance level of rice genotypes to submergence is proportional to the potential to neutralize ROS (Gill and Tuteja 2010;Fukao et al 2011;Panda and Sarkar 2013). Data explaining this relationship between the complete submergence and oxidative damage are not sufficient enough in rice, particularly in traditional rice landraces.…”