Silicon alleviates salt stress and increases antioxidant enzymes activity in leaves of salt-stressed cucumber (Cucumis sativus L.)

The antioxidant activities against superoxide radicals (O2•-), hydrogen peroxide (H2O2), hydroxyl radicals (OH•), and singlet oxygen (‘O2) was evaluated in fruit juice from different cultivars of thornless blackberries (Rubus sp.), blueberries (Vaccinium spp.), cranberries (Vaccinium macrocarpon Aiton), raspberries (Rubus idaeus L. and Rubus occidentalis L.), and strawberries (Fragaria x ananassa Duch.). Among the different cultivars, juice of ‘Hull Thornless' blackberry, ‘Earliglow' strawberry, ‘Early Black' cranberry, ‘Jewel' raspberry, and ‘Elliot' blueberry had the highest antioxidant capacity against superoxide radicals (O2•-), hydrogen peroxide (H2O2), hydroxyl radicals (OH•), and singlet oxygen (‘O2). In general, blackberries had the highest antioxidant capacity inhibition of O2•-, H2O2, and OH•. Strawberry was second best in the antioxidant capacity assay for these same free radicals. With regard to ‘O2 scavenging activity, strawberry had the highest value, while blackberry was second. Cranberries...

Scavenging capacity of berry crops on superoxide radicals, hydrogen peroxide, hydroxyl radicals, and singlet oxygen.

The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, and 30/22 degrees C) on phenolic acid, flavonol, and anthocyanin content and their antioxidant activities against peroxyl radicals (ROO(*)), superoxide radicals (O(2)(*)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radicals (OH(*)), and singlet oxygen ((1)O(2)) in fruit juice of Earliglow and Kent strawberry (Fragaria x ananassa Duch) cultivars was studied Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside (2913-9451 microg/g fresh wt), pelargonidin 3-rutinoside (247-509 microg/g fresh wt), and pelargonidin 3-glucoside-succinate (622-2440 microg/g fresh wt) were the predominant anthocyanins in strawberry fruit juice The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins Strawberry growth in high temperature conditions significantly enhanced the content of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate in strawberry juice Plants grown in the cool day and cool night temperature (18/12 degrees C) generally had the lowest phenolic acid, flavonols, and anthocyanins An increase in night temperature from 12 to 22 degrees C, with the day temperature kept constant at 25 degrees C, resulted in a significant increase in phenolic acid, flavonols, and anthocyanins These conditions also resulted in a significant increase in antioxidant capacity The highest day/night temperature (30/22 degrees C) yielded fruit with the most phenolic content as well as ROO(*), O(2)(*)(-), H(2)O(2), OH(*), and (1)O(2) radical absorbance capacity Fruit of Kent cv strawberry had higher values of phenolic acid, flavonols, anthocyanins, and antioxidant capacities than fruit of Earliglow cv strawberry under all temperature regimes

Effect of plant growth temperature on antioxidant capacity in strawberry.

Scavenging of reactive oxygen species in NaCl-stressed rice (Oryza sativa L.)—differential response in salt-tolerant and sensitive varieties

The influence of silicon (Si) (2.5 mM), sodium chloride (NaCl) (100 mM), and Si (2.5 mM) + NaCl (97.5 mM) supply on chlorophyll content, chlorophyll fluorescence, the concentration of malondialdehyde (MDA), H2O2 level, and activities of superoxide dismutase (SOD; E.C.1.15.1.1.), ascorbate peroxidase (APx; E.C.1.11.1.11.), catalase (CAT; E.C.1.11.1.6.), guaiacol peroxidase (G-POD; E.C.1.11.1.7.) enzymes, and protein content were studied in tomato (Lycopersicon esculentum Mill c.v.) leaves over 10-day and 27-day periods. The results indicated that silicon partially offset the negative impacts of NaCl stress with increased the tolerance of tomato plants to NaCl salinity by raising SOD and CAT activities, chlorophyll content, and photochemical efficiency of PSII. Salt stress decreased SOD and CAT activities and soluble protein content in the leaves. However, addition of silicon to the nutrient solution enhanced SOD and CAT activities and protein content in tomato leaves under salt stress. In contrast...

Elspeth A. MacRae

Papers

Estimation of hydrogen peroxide in plant extracts using titanium(IV)