Photosynthetic function, lipid peroxidation, and α-tocopherol content in spinach leaves during exposure to UV-B radiation

1997 ◽  
Vol 77 (3) ◽  
pp. 453-459 ◽  
Author(s):  
J. M. DeLong ◽  
K. L. Steffen
Keyword(s):  
Lipid Peroxidation ◽  
Spinacia Oleracea ◽  
Membrane Lipids ◽  
Photochemical Efficiency ◽  
Ultra Violet ◽  
Thylakoid Membranes ◽  
Tocopherol Content ◽  
Lipid Matrix ◽  
Spinacia Oleracea L ◽  
Spinach Leaves

Spinach (Spinacia oleracea L. 'Meridian') plants were irradiated for 9 h d−1 for 12 d with ultra-violet-B (UV-B) radiation [13.5 kJ m−2 d−1 of biologically effective UV-B radiation (UV-BBE) + 350 µmol m−2 s−1 of photosynthetically active radiation (PAR)] or PAR (350 µmol m−2 s−1) to determine if incipient UV-B-induced inhibition of photosynthetic function occurred in photosystem 2 (PS2) reaction centers or in the lipid matrix of thylakoid membranes. Chlorophyll concentrations (leaf area basis) in UV-B-irradiated spinach leaves were significantly lower than in PAR plants after 4, 8 and 12 d of exposure. A significant UV-B-induced rise in initial fluorescence (Fo) at days 8 and 10 was accompanied by a decline in the photochemical efficiency (Fv/Fm) ratio, indicating a reduction in the efficiency of PS2 energy harvesting and trapping. When based upon the chlorophyll content of thylakoid membranes, UV-B radiation did not alter lipid per-oxidation but did increase α-tocopherol content compared with the PAR treatment during the first 8 of the 12 exposure days. These data suggest that incipient UV-B damage to the photochemical apparatus did not occur in PS2 reaction center complexes nor in the lipid matrix of the thylakoid membranes. Photosynthetic function was more susceptible to UV-B-induced impairment than thylakoid membrane lipids were to UV-B radiation damage. Key words: ultra-violet-B radiation, chlorophyll fluorescence, lipid peroxidation, α-tocopherol

scholarly journals Processing Line Effects on Storage Attributes of Fresh-cut Spinach Leaves

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1308-1311 ◽  
Author(s):  
D. Mark Hodges ◽  
Charles F. Forney ◽  
Wendy Wismer
Keyword(s):  
Lipid Peroxidation ◽  
Electrolyte Leakage ◽  
Spinacia Oleracea ◽  
Chlorophyll B ◽  
Storage Quality ◽  
Processing Line ◽  
Hue Angle ◽  
Fresh Cut ◽  
Spinach Leaves

The degree of damage that may occur through harvesting and packing represents one of the major factors that can affect quality of fresh-cut produce. The purpose of this study was to examine the effects of different steps in a representative fresh-cut processing line on storage quality of spinach (Spinacia oleracea L.). To this end, spinach leaves were removed at successive points on the line: 1) before entry into the line (control); 2) after a shaking procedure but before initial rinsing with 10 °C water + 5 mg·L-1 chlorine dioxide; 3) after centrifugal drying; and 4) after commercial packaging. After removal from the different points in the line, the spinach samples were stored at 10 °C for 16 days, during which time malondialdehyde (MDA) concentration (lipid peroxidation assay), electrolyte leakage (membrane leakiness), chlorophyll content (a, b, and total), and color attributes (L, saturation, hue angle) were measured. Both lipid peroxidation and electrolyte leakage increased with time of storage and with stage of procesing. Electrolyte leakage increased most in material removed after the shaking procedure, but prior to hydrocooling. Overall total chlorophyll loss during storage did not change with time of removal from the processing line, although overall chlorophyll b content decreased in stored material 8 days following centrifugal drying and packaging. A more rapid loss in chlorophyll a relative to chlorophyll b over the first 8 days of storage was reflected in hue angle measurements regardless of the point of removal. The processing line under study, thus had both beneficial and detrimental effects on storage quality of spinach. Detrimental effects associated with centrifugal drying and packaging procedures could be modified to improve quality.

scholarly journals Effect of three organic fertilizers treatments on sensory evaluations of baby spinach (Spinacia oleracea L.)

2021 ◽  
Vol 27 ◽  
Author(s):  
C. Parwada ◽  
V. Chigiya ◽  
W. Ngezimana ◽  
J. Chipomho
Keyword(s):  
Spinacia Oleracea ◽  
Consumer Preferences ◽  
Organic Fertilizer ◽  
Organic Fertilizers ◽  
Teachers College ◽  
Spinacia Oleracea L ◽  
Sensory Evaluations ◽  
Hedonic Scale ◽  
Major Factors ◽  
Spinach Leaves

Sources of fertilizer are one of the major factors influencing baby spinach leaf texture, sweetness, bitterness and after-taste. However, the effects of fertilizer sources on baby spinach growth performance and consumer preferences are not known. A survey was carried out at the Seke Teachers’ College (SKC) community, Zimbabwe to determine the consumer preferences on the baby spinach grown on the organic fertilizer (cattle, poultry and goat manures) as well as on control inorganic  fertilizers (7% N, 14% P, 7% K). The study used 32 females and 30 males as panellists for sensory evaluations. Organoleptic tests were performed for the baby spinach leaves using a panel of 62 testers. An interval line scale (16 cm long) was used to measure the liking for sweetness, colour, bitterness and after-taste. A 9-point hedonic scale was used to decide the overall preferences. Organoleptic tests showed significant differences (P<0.05) in appearance and taste between the inorganic and organic fertilizers used. The baby spinach leaves grown on organic fertilizers was preferred more compared to that grown on inorganic fertilizer (control). Therefore, it is recommended to use organic fertilizers in baby spinach production in order to satisfy consumer preferences.

Characterization of Multiple Acid Phosphatases in Salt-Stressed Spinach Leaves

1987 ◽  
Vol 14 (2) ◽  
pp. 117 ◽  
Author(s):  
SM Pan
Keyword(s):  
Molecular Weight ◽  
Salt Stress ◽  
Gel Electrophoresis ◽  
Spinacia Oleracea ◽  
Acid Phosphatases ◽  
Multiple Forms ◽  
Spinacia Oleracea L ◽  
Hydroponically Grown ◽  
Spinach Leaves

Incremental salt stress brought about a clear enhancement of the activity of acid phosphatases in hydroponically grown spinach (Spinacia oleracea L.) leaves. Sephacryl S-200 chromatography of the enzyme fraction revealed multiple forms of acid phosphatases of high (300 000), intermediate (100 000), and low (35 000) molecular weight in control and salt-stressed spinach leaves. A similar zymogram of acid phosphatases, showing at least six bands in polyacrylamide disc gel electrophoresis, was observed for control and stressed leaves. However, promotive effects of incremental salt stress on the activity of acid phosphatases were more pronounced in high molecular weight acid phosphatases. Substrate specificity and differential effects of some ions on the multiple acid phosphatases were also examined for control and salt-stressed leaves.

scholarly journals Response of Baby Spinach (Spinacia oleracea L.) to Photoselective Nettings on Growth and Postharvest Quality

HortScience ◽  
2017 ◽  
Vol 52 (5) ◽  
pp. 719-724 ◽  
Author(s):  
Ambani R. Mudau ◽  
Puffy Soundy ◽  
Fhatuwani N. Mudau
Keyword(s):  
Antioxidant Activity ◽  
Spinacia Oleracea ◽  
Storage Period ◽  
Postharvest Quality ◽  
Flavonoid Content ◽  
C Storage ◽  
Spinacia Oleracea L ◽  
High Level ◽  
Spinach Leaves

Manipulation of microenvironments by means of photoselective nettings is widely used to improve the productivity and quality of high-value vegetables. The aim of this study was to investigate the effect of photoselective nettings on growth, productivity, and postharvest quality attributes of baby spinach. Baby spinach cv. Ohio was grown from seeds, and the trial was repeated. Plants were planted in an open field (control) and under closed nets, viz., black, pearl, yellow, and red nets. At harvest, baby spinach leaves were subjected to 4, 10, and 20 °C storage temperatures for 12 days. Crops grown under black nets and stored at 4 °C retained higher level of antioxidant activity (0.23 g·kg−1), whereas the least level of antioxidant activity was observed in baby spinach grown under red and yellow shade nets (0.01 g·kg−1). Similar trend was evident with flavonoid content where baby spinach leaves grown under black nets maintained high level of flavonoids at 4, 10, and 20 °C during storage period compared with other shade nets and the control. The study control showed a better potential in retaining antioxidant activity over red and yellow shade nets. Results showed that black shade nettings have the potential to reduce water loss, decay incidents, and maintain flavonoid content and antioxidant activity followed by pearl and yellow nets.

scholarly journals 126 Antioxidant Responses in Detached Leaves of Two Cultivars of Spinach (Spinacia oleracea L.) Differing in Their Senescence Rates

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 411A-411
Author(s):  
D. Mark Hodges ◽  
Wendy V. Wismer ◽  
Charles F. Forney
Keyword(s):  
Hydrogen Peroxide ◽  
Lipid Peroxidation ◽  
Spinacia Oleracea ◽  
Total Glutathione ◽  
Antioxidant Responses ◽  
Spinacia Oleracea L ◽  
Detached Leaves ◽  
Hydrogen Peroxide Accumulation ◽  
Growth Chambers ◽  
Field Plots

The responses of certain antioxidants in detached leaves of two cultivars of spinach (Spinacia oleracea L.) differing in their senescence rates were assessed during storage in order to explore the significance of these antioxidants in senescence regulation and dynamics. To identify spinach cultivars differing in their senescence rates, 10 cultivars were grown in field plots, harvested at maturity, and their leaves detached and stored at 10 °C in the dark. At the point of harvest (d 0) and on d 5, 8, 12, and 15, samples were analyzed for lipid peroxidation (MDA), chlorophyll loss, and electrolyte leakage. The cultivars were also grown in laboratory growth chambers to corroborate field results. Two cultivars that were consistently identified as having relatively high (Spokane F1) and low (BJ 412 Sponsor) senescence rates were grown in growth chambers for 45 d, harvested at maturity, and their leaves detached and stored as above. At the point of harvest (d 0) and on d 4, 8, 12, 16, and 20, samples were analyzed for (i) activities of ascorbate peroxidase (ASPX; EC 1.11.1.11), catalase (CAT; EC 1.11.1.6), and superoxide dismutase (SOD; EC 1.15.1.1), and (ii) concentrations of MDA, total ascorbate, reduced ascorbate (AsA), oxidized ascorbate (DAsA), total glutathione, reduced glutathione (GSH) and oxidized glutathione (GSSG). Although MDA accumulated in leaves of both cultivars concomitant with time after detachment, levels became significantly higher in Spokane. Activities of ASPX declined in Spokane leaves following detachment but activities of SOD and levels of glutathione increased in this cultivar. GSH/GSSG increased in `Sponsor', but dramatically more so in `Spokane'. Ascorbate concentrations did not diminish in leaves of `Spokane' to the degree that they did in `Sponsor' tissue. DAsA/AsA values did not decrease in `Spokane' leaves following detachment, though they did in those of `Sponsor'. It is argued that declining activities of ASPX and levels of ascorbate and increasing activities of SOD manifested in accumulation of hydrogen peroxide in Spokane, leading to a greater potential for lipid peroxidation in this variety than for Sponsor. SOD activities and glutathione levels may have increased as a result of elevated oxidative stress in Spokane. Increased hydrogen peroxide accumulation in `Spokane' relative to `Sponsor' may have contributed to an increased rate of senescence in the leaves of this cultivar.

scholarly journals Melatonin and plant growth-promoting rhizobacteria alleviate the cadmium and arsenic stresses and increase the growth of Spinacia oleracea L.

2020 ◽  
Vol 66 (No. 5) ◽  
pp. 234-241 ◽  
Author(s):  
Mahnoor Asif ◽  
Arshid Pervez ◽  
Usman Irshad ◽  
Qaisar Mehmood ◽  
Rafiq Ahmad
Keyword(s):  
Lipid Peroxidation ◽  
Antioxidant Enzymes ◽  
Plant Growth ◽  
Spinacia Oleracea ◽  
Plant Growth Promoting Rhizobacteria ◽  
Exogenous Melatonin ◽  
Spinacia Oleracea L ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
The Impact

Melatonin (N-acetyl-5-methoxytryptamine) is a recently discovered natural product that helps the plant to cope with environmental stresses. In the same way, plant growth-promoting rhizobacteria colonise plant roots and enhance plant stress tolerance. To study the impact of exogenous melatonin and Bacillus licheniformis on the growth of Spinacia oleracea L. seedlings were treated with 100 µmol exogenous melatonin and B. licheniformis under cadmium (Cd) and arsenic (As) stresses by a pot experiment. Different plant growth parameters, antioxidant enzymes, and lipid peroxidation were studied. The results showed that melatonin application and B. licheniformis inoculation alleviated As and Cd toxicity by significantly reducing the negative impacts of stresses and increasing the fresh and dry weight as well as preventing the damage to the chlorophyll content of S. oleracea L. Moreover, supplementation of melatonin, and B. licheniformis, enhanced activities of antioxidant enzymes superoxide dismutase, peroxidase, catalase, thus acting as a line of defense against As and Cd stresses. Similarly, lipid peroxidation was also inhibited by exogenous melatonin and B. licheniformis inoculation. Exogenous application of melatonin and inoculating roots of S. oleracea L. with B. licheniformis found to ameliorate the harmful effects of As and Cd contamination.

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