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

Abstract

<jats:p>Recovery from submergence stress is vital for plant regrowth. The objective of this study was to characterize plant growth, carbohydrate, and antioxidant metabolism of creeping bentgrass (<jats:italic>Agrostis stolonifera</jats:italic>) to foliar application of nitrogen and cytokinin (CK) after de-submergence. Creeping bentgrass (cv. Penncross and 007) were submerged under the water for 14 days and then foliar-sprayed at 1, 2, 3, 7, and 14 days after de-submergence with six types of chemical treatments, respectively: 1) water (W); 2) 10 m<jats:sc>m</jats:sc> urea (N10); 3) 20 m<jats:sc>m</jats:sc> urea (N20); 4) 10 µ<jats:sc>m</jats:sc> CK; 5) N10 with CK (N10CK); and 6) N20 with CK (N20CK). Leaves were harvested at 20 days after chemical applications for various measurements. Compared with the nonstressed plants, plant height (HT), chlorophyll index (Chl), leaf dry weight (DW), water-soluble carbohydrate content (WSC), activities of superoxide dismutase (SOD), and ascorbate peroxidase (APX) decreased, but catalase (CAT) and peroxidase (POD) activities, malondialdehyde (MDA), and total soluble protein (TSP) content increased in both cultivars exposed to 14 days of submergence. After de-submergence, plants treated with N alone (N10, N20) or combined with CK (N10CK, N20CK) generally had higher HT, DW, Chl, TSP, and a lower amount of MDA, compared with treatments of W or CK alone, whereas treatment using CK resulted in higher WSC for both cultivars. Foliar applications of N and CK had some effect on SOD, CAT, POD, and APX activities after de-submergence, but the effects were not consistent across chemicals and cultivars. The results indicated that foliar application of N or combined with CK promoted plant growth and reduced lipid peroxidation after de-submergence. The results also suggested a more positive role of foliar N application in comparison with a complex regulation of CK on creeping bentgrass regrowth after de-submergence.</jats:p>

Signal Dynamics and Interactions during Flooding Stress

“…Postsubmergence ROS damage is parallel to oxidative damage during hypoxic conditions, in which ROS disrupts the photosynthetic apparatus (Luo et al, 2011;Panda and Sarkar, 2012;Alpuerto et al, 2016) and, consequently, hinders photosynthetic recovery and the replenishment of carbohydrate reserves (Bhowmick et al, 2014;Gautam et al, 2016). During reoxygenation and reillumination, ROS and photoinhibition can further trigger desiccation stress (Setter et al, 2010), leaf senescence (Gautam et al, 2016;Liu and Jiang, 2016), and cell death (Tamang et al, 2014). Upon reoxygenation, ROS accumulation likely occurs due to a combination of reduced scavenging capacity and increased ROS production (Rhoads et al, 2006;Blokhina and Fagerstedt, 2010;Shapiguzov et al, 2012).…”

Association of Candidate Genes With Submergence Response in Perennial Ryegrass

“…Carbohydrate consumption and conservation play an important role in stress tolerance, and depletion of carbohydrates under submergence stress largely influenced plant growth and survival (Setter and Laureles, 1996; Sasidharan et al, 2013; Liu and Jiang, 2016). In C3 cool-season temperate grasses, fructan is a major component of non-structural carbohydrate reserve (Chatterton et al, 1989).…”

“…Numerous physiological and molecular alterations are involved in genotypic variations in response to submergence stress and recovery ( Vashisht et al, 2011 ; Yu et al, 2012 ; Van Veen et al, 2013 ; Campbell et al, 2015 ). Carbohydrate consumption and conservation play an important role in stress tolerance, and depletion of carbohydrates under submergence stress largely influenced plant growth and survival ( Setter and Laureles, 1996 ; Sasidharan et al, 2013 ; Liu and Jiang, 2016 ). In C3 cool-season temperate grasses, fructan is a major component of non-structural carbohydrate reserve ( Chatterton et al, 1989 ).…”

“…Antioxidant metabolisms may promote submergence tolerance and recovery upon reoxygenation in plants ( Tan et al, 2010 ; Liu and Jiang, 2015 , 2016 ). The increased shoot activities of catalase (CAT) and peroxidase (POD) were more pronounced in relatively slow-growing genotypes, while greater reductions in root activities of superoxide dismutase (SOD), CAT, POD and ascorbate peroxidase (APX) treatments and increased malondialdehyde concentrations were found in the fast growing genotypes of perennial ryegrass ( Liu and Jiang, 2015 ).…”

“…The increased shoot activities of catalase (CAT) and peroxidase (POD) were more pronounced in relatively slow-growing genotypes, while greater reductions in root activities of superoxide dismutase (SOD), CAT, POD and ascorbate peroxidase (APX) treatments and increased malondialdehyde concentrations were found in the fast growing genotypes of perennial ryegrass ( Liu and Jiang, 2015 ). Submergence also decreased activities of SOD and APX but increased CAT and POD activities in two creeping bentgrass cultivars ( Liu and Jiang, 2016 ). Moreover, reoxygenation after de-submergence can cause oxidative injury due to increased oxygen uptake and accelerated mitochondrial activities, potentially leading to lipid peroxidation and membrane leakage ( Blokhina et al, 2003 ).…”