Exogenous Selenium Mitigates Salt Stress in Soybean by Improving Growth,Physiology,Glutathione Homeostasis and Antioxidant Defense

The mechanism of selenium(Se)-induced salt tolerance was studied in moderately sensitive soybean(Glycine max L.)plants.To execute this view,soybean plants were imposed with salt stress(EC 6 dS m^(−1))applying NaCl.In other treatments,Se(0,25,50 and 75μM Na_(2)SeO_(4))was sprayed as co-application with that level of salt stress.Plant height,stem diameter,leaf area,SPAD value decreased noticeably under salt stress.Altered proline(Pro)level,together with decreased leaf relative water content(RWC)was observed in salt-affected plants.Salt stress resulted in brutal oxidative damage and increased the content of H_(2)O_(2),MDA level and electrolyte leakage.Exogenous Se spray alleviated oxidative damage through boosting up the antioxidant defense system by increasing the activity of antioxidant enzymes such as catalase(CAT),peroxidase(POD)and glutathione reductase(GR),as well as by improving non-enzymatic antioxidants like glutathione(GSH)and GSH/glutathione disulfide(GSSG).The upregulated antioxidant defense system,restored Pro and leaf RWC,higher SPAD value conferred better growth and development in Se-sprayed salt-affected soybean plants which altogether put forth for the progressive yield contributing parameters and finally,seed yield.Among different doses of Se,soybean plants sprayed with 50μM Na_(2)SeO_(4)showed better salt tolerance.

Drought-Mediated Modulation in Metabolomic Profiling of Nigella Sativa Leaf, Growth, Ecophysiology and Antioxidants

Abiotic stresses,including drought,have been found to affect the growth and medicinal quality of numerous herbs.The proposed study aims to study the effects of different drought regimes on the metabolic profile,growth,ecophysiology,cellular antioxidants,and antioxidant potential of Nigella sativa(Black cumin)leaf.Forty-day-old seedlings of N.sativa were exposed to three regimes of drought(control,moderate and high)for a week.UPLCMS/MS metabolic profile of the leaf reveals the presence of more than a hundred metabolites belonging to anthocyanins,chalcones,dihydro flavonoids,flavonoids,flavanols,flavones,flavonoid carbonoside,isoflavones,etc.Drought was found to alter the contents of identified metabolites.Drought stress-induced oxidative stress and increased production of hydrogen peroxide and superoxide anions.Physiological changes,activities of antioxidant enzymes,contents of antioxidants,and proline were significantly high under drought to protect against the low water regimes.Furthermore,stressed leaf extract had higher antioxidant potential.Thus,N.sativa leaf bears multiple metabolic pathways and can tolerate a higher degree of drought or osmotic stress.

Assessment of the Contribution of Foliar Trichomes towards Allelopathy

Plant trichomes vary in their structure and cellular composition.Glandular trichomes contain a bulk of specific(secondary)metabolites of diverse nature.Trichomes are connected with various adaptive processes,which include protection against herbivores and pathogens as well.Our study investigates the allelopathic contribution of structures present on the leaf surface of Nicotiana plumbaginifolia Viv.against seedling growth of Cicer arietinum L.The infusion obtained after dipping Nicotiana leaves in Dichloromethane(DCM)for 10 seconds(s)was the most phytotoxic among all the infusions.The observed inhibition in Cicer growth was not only dependent on type of infusion but also the concentration.Scanning electron microscopy of the leaf samples showed the modifications in trichomes under the influence of the different concentration of DCM.Glandular trichomes were most dehydrated at 10 seconds in DCM,suggesting their role for the observed allelopathy.Such study on the biochemistry of trichomes and their phytotoxicity may develop highly valuable objects for plant metabolic engineering.