Reversion of deleterious effects of salt stress by activation of ROS detoxifying enzymes via foliar application of 24-epibrassinolide in rice seedlings

Abstract

We evaluated the effects of foliar application of 24-epibrassinolide (EBL) on growth, oxidative metabolism and water relations of rice seedlings cv. J-104, stressed with 100 mmol L -1 NaCl for 7 days and recovered without NaCl in the nutrient solution during the next 15 days. Measurements were made at the beginning, at the end and after recovery from salt stress. Salinity decreased growth but the effects were observed during the recovery period. Foliar application of EBL restored growth in salt stressed seedlings. Water relations were affected by salt stress but spraying EBL only restored turgor potential. Proline concentration increased after recovery in salt stressed seedlings and application of EBL reverted this effect by 35 %. Lipid peroxidation and protein oxidation increased with salt stress and seedlings sprayed with EBL showed lower damage to membranes and proteins than salt stressed plants without EBL application. Antioxidant enzymes responded variably to salt stress, peroxidases and SOD either decreased or were little affected by salt stress, whereas catalase activity increased with salinity. The effect of EBL on antioxidant enzymes was in general to increase activities of catalase, ascorbate peroxidase and SOD. The protective effects of EBL of salt stressed rice seedlings may be associated with a decrease of oxidative stress probably modulated by proline accumulation via catalase and SOD, evidenced by a reduction of lipid peroxidation and proteins oxidation, and maintenance of chlorophylls concentration.

Unraveling the roles of brassinosteroids in alleviating drought stress in young Eucalyptus urophylla plants: Implications on redox homeostasis and photosynthetic apparatus

“…Decreases in O 2 − and H 2 O 2 levels in plants sprayed with 100 nM EBR are related to the increases in the activities of SOD, CAT, APX, and POX enzymes promoted by the steroid (Figures 2 and 5). The lower level of O 2 − is associated with the increased activity of the SOD enzyme, which is responsible for converting O 2 − into H 2 O 2 and O 2 (Gill & Tuteja, 2010; Reyes Guerrero et al, 2015), while the reduction in H 2 O 2 concentrations is linked to APX activity. This enzyme is responsible for dismutation of H 2 O 2 into H 2 O and O 2 , contributing to cell detoxification and reducing oxidative stress (El‐Beltagi & Mohamed, 2013; Gratão et al, 2005).…”

“…This molecule can mitigate oxidative stress (Talaat et al, 2015) by stimulating the activity of antioxidant enzymes (Ali et al, 2008) and increasing growth (Shahbaz et al, 2008). In addition, EBR regulates the tolerance mechanisms to salinity stress (Reyes Guerrero et al, 2015), low and high temperatures (Cui et al, 2016; Wu et al, 2014), heavy metal toxicity (Ramakrishna & Rao, 2015), nutrient uptake (Karlidag et al, 2011), and nutrient deficiency (Wang, Li, & Zhang, 2015).…”

Sweet Pepper (Capsicum annuum L.) Fruits Contain an Atypical Peroxisomal Catalase That Is Modulated by Reactive Oxygen and Nitrogen Species

“…Nevertheless, castor bean endosperm catalase activity has been found to increase after treatment with H 2 O 2 . The effects of a diverse range of pro-oxidant situations, which either stimulate or depress catalase enzyme activity, have been reported [74,75,76,77,78]. The low concentrations of H 2 O 2 used to inhibit the pepper fruit enzyme are somewhat atypical, as spectrophotometric determination of catalase commonly requires higher levels of H 2 O 2 [3].…”

Salt pretreatment alleviated salt-induced photoinhibition in sweet sorghum

“…Besides soil remediation, it is feasible to combat salinity by improving crop salt tolerance (Lea et al 2004;Schroeder et al 2013). Eco-physiological methods seem more convenient and easier to be applied in agricultural practice, in contrast to genetic engineering and conventional breeding (Yan et al 2013c;Guerrero et al 2014). For example, salt pretreatment with sublethal level of salinity has been evidenced as an available way for enhancing crop salt tolerance (Amzallag et al 1990;Umezawa et al 2000;Djanaguiraman et al 2006;Tajdoost et al 2007;Saha et al 2012).…”