Effect of Salinity Stress on Antioxidant Defense System of Niger (<i>Guizotia abyssinica</i> Cass.)

Abstract

Salinity is one of the principal abiotic stresses that affect plant productivity by inducing osmotic stress, which in turn, causes oxidative stress. Plants respond to this oxidative stress by adjusting levels of antioxidants and associated components. 10-day old seedlings of Niger were evaluated for abiotic stress response in terms of antioxidants and antioxidant enzymes over 72 h in presence of up to 500 mM NaCl in combination with CaCl 2 . Stress markers: H 2 O 2 , lipid peroxidation, antioxidants; ASC and GSH and antioxidant enzymes such as POX, APX and GR were significantly elevated, while CAT was reduced. The response was concentration and time-dependent up to 300 mM NaCl and fluctuated beyond. Metabolic enzymes β-amylase and acid phosphatase exhibited moderate increase relative to controls. The parameters indicated tolerance of the plants to salinity up to 300 mM over 48 h.

Modulation of Antioxidant Enzymes System by Kinetin in Salt Stressed Shoots of Zea Mays

“…It is also proposed that increasing NaCl stress lead to increased H2O2 production and level of ascorbate peroxidase increased to detoxify H2O2 which also indicating their role in detoxification of H2O2 under high salinity stress 38 . NaCl mediated ascorbate peroxidase increase has been reported in leaves of Lycopersicon pennelli (100mM NaCl) 1 , leaves of barley (0 to 400mM NaCl for 3 days) 37 , Phaseolus vulgaris (400mM NaCl for 48 hours) 35 , nodal segments of chickpea (0-200mg/L NaCl) 15 , pea leaf of 7 cultivars (75mM NaCl for 14 days) 14 Yasar et al 2016 and 10-day old niger plants (0-500mM NaCl) 16 . On the contrary, NaCl mediated inhibition of APX has been reported in Lycopersicon esculentum (0 to 150mg NaCl for 7 days) 31 , Zea mays (50 and 100mM salt stress) 33 and Daucus carota (0-150 mM NaCl for 90 days) 9 .…”

“…Kavas et al (2015) 13 treated two 12-day old peanut cultivars with 0/100/ 300mM NaCl for 16 days and found decreased catalase activity in both. Naik et al (2016) 16 treated 10-day old niger plants with 0-500mM NaCl for 24/48/72 hours and reported reduction in catalase activity. 3 grew the maize plants in 100mM salt stress and reported decreased reduced GR activity in roots of salt-sensitive genotype and no change in roots of salt-tolerant genotype.…”

“…However, majority of reports are of increase. Salt stimulated GR increase has also been reported in a number of plants like Gossypium hirsutam (0-150mM NaCl for 30 days) 34 , Phaseolus vulgaris (5-day old plants with 400mM NaCl for 48 hours) 35 , Atriplex hortensis (260mM NaCl for 3 months) 32 , Zea mays (21 day old two maize varieties in 0/50mM/100mM NaCl for 15 days) 35 , Arachis hypogea (two 12-day old peanut cultivars with 0/100/ 300mM NaCl for 16 days) 13 , chickpea (0-200 mg L −1 NaCl) 15 , Brassica juncea (250mM NaCl stress for 6 hours) 17 and Guizotia abyssinica (0-500mM NaCl for 24/48/72 hours) 16 .…”

“…According to the previous studies whose result resemble with present study, it can be suggested that lipid peroxidation was due to high MDA level in plant which itself is produced due to accumulation of H2O2 and lipid peroxidation can also be induced via an enzymatic pathway by the activity of lipoxygenases, which have been observed to be induced by salt stress 39,1 . 15 , Pisum sativum 14 and Guizotia abyssinica 16 .…”

“…The NaCl stress is also expected to generate ROS. The antioxidant enzymes get stimulated, by endogenous or exogenous factors, to counteract the detrimental effects of ROS 12 , Arachis hypogea 13 , Pisum sativum 14 , chickpea 15 , Guizotia abyssinica 16 and Brassica juncea 17 .…”