Leaf Ascorbic Acid Research Articles

Resilient mechanism of strigolactone (GR24) in regulating morphological and biochemical status of maize under salt stress

Strigolactones (SLs), relatively recent plant growth regulators, bolster plant resilience in challenging environmental conditions and augment signaling networks. Salinity, a well-established abiotic stressor, threatens global crop cultivation and productivity. We hypothesized that the synthetic SL analogue GR24 could alleviate salinity stress in maize by reducing oxidative damage and enhancing various growth and physiological attributes. To explore this hypothesis, we subjected two maize hybrids, PB-ProA-2018 and PB-ProA-2019, to seed priming with three GR24 concentrations (non-soaked, water-soaked, 0.001, 0.01, 0.1 mg/L) for 16 h. Seeds were then germinated in sand culture under two salt stress levels [ 0 (Control) and 100 mM NaCl] and nourished with Hoagland's nutrient medium. Salt stress significantly stunted maize growth attributes. The pre-soaking seed treatment with 0.01 mg L⁻1 GR24 demonstrated a significant enhancement in plant growth metrics, yielding a 31.3% increase in root length and a 62% augmentation in total leaf area per plant, in comparison to non-soaked yet stressed plants. Salt stress led to increased activities of catalase and peroxidase, along with higher levels of leaf ascorbic acid, malondialdehyde, H₂O₂, glycine betaine, and free proline, compared to control seedlings. Pre-soaking with 0.01 mg L−1 GR24 further upregulated superoxide dismutase (SOD) by 29.6%, peroxidase (POD) by 68.3%, catalase (CAT) by 25%, ascorbic acid by 23.1%, free proline by 42.3%, and total phenolics content by 13%, compared to stressed counterparts. Notably, the 0.01 mg L−1 GR24 concentration exhibited superior efficacy in mitigating salt stress effects, with PB-ProA-2019 outperforming PB-ProA-2018 among the maize hybrids. These findings advance our understanding of SLs' potential in alleviating salinity stress in maize, offering valuable insights for crop resilience enhancement.

Effect of strigolactone on growth, photosynthetic efficiency, antioxidant activity, and osmolytes accumulation in different maize (Zea mays L.) hybrids grown under drought stress

ABSTRACT Drought alters plant physiology, morphology, and biochemical pathways, necessitating effective mitigation strategies. Strigolactones (SLs) are phytohormones known to enhance plant growth under abiotic stress. However, their specific impact on drought stress in maize remains unclear. This study aimed to determine the optimal SL concentration for mitigating drought stress in two maize hybrids (HY-1898, FH-1046). Maize plants were subjected to 60% field capacity drought stress in a pot experiment. After 40 d, different concentrations (0, 0.001, 0.01, and 0.1 mg L−1) of the synthetic SL analogue GR24 were applied to evaluate their effects on growth features, photosynthesis attributes, and osmolyte accumulation in the maize hybrids. Results showed that exogenous SL application significantly increased photosynthetic pigments in maize hybrids under drought stress. Chlorophyll content, gas exchange characteristics, net CO2 assimilation rate, stomatal conductance, water use efficiency, and antioxidant activities were enhanced by GR24. Leaf ascorbic acid and total phenolics also increased with SL application. Organic osmolytes, such as glycine betaine and free proline, were elevated in both maize hybrids under drought stress. Yield-related parameters, including cob diameter, cob weight, number of seeds per cob, and number of seeds per plant, were significantly increased by GR24 under drought stress. Our findings highlight the potential of GR24 foliar application to mitigate drought stress and promote maize growth and grain yield in a concentration-dependent manner. The minimum effective SL concentration against drought stress was determined to be 0.01 mg L−1. Overall, foliar application of GR24 could serve as a sustainable approach for drought tolerance in agriculture.

Effect of Sodium Selenate and Selenocystine on Savoy Cabbage Yield, Morphological and Biochemical Characteristics under Chlorella Supply.

Biofortification of Brassica oleracea with selenium (Se) is highly valuable both for human Se status optimization and functional food production with direct anti-carcinogenic activity. To assess the effects of organic and inorganic Se supply for biofortifying Brassica representatives, foliar applications of sodium selenate and selenocystine (SeCys2) were performed on Savoy cabbage treated with the growth stimulator microalgae Chlorella. Compared to sodium selenate, SeCys2 exerted a stronger growth stimulation of heads (1.3 against 1.14 times) and an increase of leaf concentration of chlorophyll (1.56 against 1.2 times) and ascorbic acid (1.37 against 1.27 times). Head density was reduced by 1.22 times by foliar application of sodium selenate and by 1.58 times by SeCys2. Despite the greater growth stimulation effect of SeCys2, its application resulted in lower biofortification levels (2.9 times) compared to sodium selenate (11.6 times). Se concentration decreased according to the following sequence: leaves > roots > head. The antioxidant activity (AOA) was higher in water extracts compared to the ethanol ones in the heads, but the opposite trend was recorded in the leaves. Chlorella supply significantly increased the efficiency of biofortification with sodium selenate (by 1.57 times) but had no effect in the case of SeCys2 application. Positive correlations were found between leaf and head weight (r = 0.621); head weight and Se content under selenate supply (r = 0.897-0.954); leaf ascorbic acid and total yield (r = 0.559), and chlorophyll (r = +0.83-0.89). Significant varietal differences were recorded for all the parameters examined. The broad comparison performed between the effects of selenate and SeCys2 showed significant genetic differences as well as important peculiarities connected with the Se chemical form and its complex interaction with Chlorella treatment.

Comparison of 18 Iranian caprifig cultivars based on some morphological and biochemical parameters

Caprifig is a valuable candidate for fig breeding programs as it typically grows naturally under non-optimal conditions. The present study was carried out to evaluate the biochemical/morphological characteristics of 18 caprifig cultivars indigenous to the Darab region/southern Iran with 4 replications in a completely randomized block design. From each cultivar, healthy uniform leaf samples and spring fruits were taken and analyzed. Our results showed that 'Naneghasem' had the highest leaf α-tocopherol and polyphenol concentration. The highest leaf ascorbic acid concentration was obtained from the Gol Khengi cultivar (17.03 μg g-1 fresh weight). Also, the contents of chlorophyll, carotenoids, and anthocyanins were significantly different among the studied cultivars. Various cultivars had different absorption potentials for essential elements as macro and micronutrients concentration in the leaves were statistically different in various caprifigs; 'Naneghasem' had the highest Ca (4.46 mg g-1 dry weight) and Fe (67.71 mg kg-1 dry weight) concentration and the highest leaf K concentration (22.46 mg g-1 dry weight) was observed in 'Mahali Layzengan'. In conclusion, 'Naneghasem' was evaluated as a cultivar which seems to be more morphologically- and biochemically-distant from other studied caprifig varieties and probably more adaptable/tolerant to environmental conditions.

Assessment of air pollution tolerance index of Murraya paniculata (L.) Jack in Kolkata metro city, West Bengal, India

Constant bursting of the city frontiers is taking a massive toll on natural vegetation, deteriorating thereby the purity of the clean air. Biomonitoring of airborne pollutants through creation of green belts has become the only alternative to provide natural filtering barrier. The present study was constructed to evaluate the air pollution tolerance index (APTI) of a commonly found evergreen plant species in Kolkata, Murraya paniculata, based on leaf attributes. PAHs accumulating ability of the plant species was also examined so as to establish the species' potential in monitoring of PAHs. M. paniculata was found to be tolerant (APTI: 19.78 ± 1.20–31.12 ± 0.72) towards air pollution with dust capturing potential between 0.85 ± 0.04–2.26 ± 0.02 mg cm−2. Correlation analysis unveiled the strong relationship of foliar dust with leaf ascorbic acid (r = 0.931), leaf extract pH (r = 0.985), leaf RWC (r = −0.822), total carotenoids (r = −0.862) and total chlorophyll (r = −0.76). APTI was found to be correlated positively to ascorbic acid and foliar pH and negatively to total chlorophyll and RWC. Changes in leaf surface micromorphology due to particulate pollution were also endorsed by SEM-EDX analysis. Findings revealed that Murraya paniculata has the tolerance and efficiency of trapping both lighter and heavier PAHs, proving its ability for biomonitoring of atmospheric pollution.

Growth, biochemical quality and antioxidant capacity of coriander leaves under organic and inorganic fertilization programs

BackgroundSoil salinity buildup and soil degradation are emerging challenges in cropping systems practicing high chemical fertilization. Application of biostimulants and organic fertilizers are better deserve agricultural sustainability and are generally reflected in more nutritious foods than chemical fertilization.Materials and methodsIn this study, the growth, quality and antioxidant capacity of coriander (Coriandrum sativum L.) were evaluated under application of organic and biological compared to chemical fertilization in a pot experiment. Different soil fertilization treatments including vermicompost (20% pot volume), cow manure (20% pot volume), biophosphate (as seed inoculation), glycine amino acid (as a biostimulant at 300 mg/kg soil), mixed NPK fertilizer (at 600 mg/kg soil) and unfertilized control were applied to plants under a completely randomized design with four replications.ResultsThe results showed that application of organic fertilizers mainly vermicompost and glycine, and to lesser extent NPK fertilizer significantly increased many growth, yield and biochemical quality traits of coriander including root and shoot biomass, leaf SPAD value, ascorbic acid, mineral nutrients, flavonoids and antioxidant activity compared to control plants. Fertilization practices resulted in higher biomass production of root (all treatments) and shoot (all treatments except biophosphate) than control plants. Leaf minerals including N and K (in vermicompost, NPK and glycine treatments), leaf P and Fe (in vermicompost and glycine treatments), leaf Zn (in vermicompost treatment) were significantly increased compared to control plants. Application of manure recorded the lowest leaf Ca and total phenols, while the highest leaf Ca was in vermicompost and glycine-treated plants and the highest leaf phenols was in vermicompost treatment. Application of glycine resulted in the highest leaf ascorbic acid as well as catalase enzyme activity. Leaf antioxidant capacity was significantly higher in vermicompost, glycine and NPK treatments compared to control plants. Leaf carotenoids, peroxidase activity, the concentration of Mg, Cu and Mn were not significantly affected by treatments.ConclusionThe results indicate that cow manure and biophosphate treatments were not much effective on plant growth; however, vermicompost and glycine showed promising improvement of coriander growth and antioxidant capacity even more than NPK fertilization.Graphic

Ozone uptake at night is more damaging to plants than equivalent day-time flux

Main conclusionPlants exposed to equivalent ozone fluxes administered during day-time versus night-time exhibited greater losses in biomass at night and this finding is attributed to night-time depletion of cell wall-localised ascorbate.The present study employed Lactuca sativa and its closest wild relative, L. serriola, to explore the relative sensitivity of plants to ozone-induced oxidative stress during day-time versus night-time. By controlling atmospheric ozone concentration and measuring stomatal conductance, equivalent ozone uptake into leaves was engineered during day and night, and consequences on productivity and net CO2 assimilation rate were determined. Biomass losses attributable to ozone were significantly greater when an equivalent dose of ozone was taken-up by foliage at night compared to the day. Linkages between ozone impacts and ascorbic acid (AA) content, redox status and cellular compartmentation were probed in both species. Leaf AA pools were depleted by exposure of plants to darkness, and then AA levels in the apoplast and symplast were monitored on subsequent transfer of plants to the light. Apoplast AA appeared to be more affected by light–dark transition than the symplast pool. Moreover, equivalent ozone fluxes administered to leaves with contrasting AA levels resulted in contrasting effects on the light-saturated rate of CO2 assimilation (Asat) in both species. Once apoplast AA content recovered to pre-treatment levels, the same ozone flux resulted in no impacts on Asat. The results of the present investigation reveal that plants are significantly more sensitive to equivalent ozone fluxes taken-up at night compared with those during the day and were consistent with diel shifts in apoplast AA content and/or redox status. Furthermore, findings suggest that some thought should be given to weighing regional models of ozone impacts for extraordinary night-time ozone impacts.

Abscisic acid enhances tolerance to spring freeze stress and regulates the expression of ascorbate–glutathione biosynthesis-related genes and stress-responsive genes in common wheat

The present study showed that exogenous abscisic acid (ABA) pre-treatment remarkably increases the freeze tolerance of common wheat (Triticum aestivum L.) seedlings at the anther connective tissue formation phase (ACFP) and tetrad developmental phase. After 3-day freeze stress, ABA pre-treatment significantly increases the content of soluble sugar, soluble protein, and proline, activities of superoxide dismutase (SOD) and peroxidase (POD) and decreases hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels. Under freeze stress conditions, ABA treatment at the ACFP and tetrad developmental phase resulted in a marked increase in leaf ascorbic acid (ASA) and glutathione (GSH) levels. Temporal and spatial expression patterns of eight genes encoding ASA–GSH synthesis-related enzymes and eight stress-responsive genes were measured using quantitative real-time PCR (qRT-PCR). The results showed that ABA temporally regulated the transcript levels of these genes. Moreover, these genes were differentially expressed in ABA-treated wheat seedlings between the ACFP and tetrad developmental phase during freeze stress. These results implied that exogenous ABA increases the levels of GSH and ASA in freeze stressed wheat seedlings in time- and developmental phase-specific manners. Furthermore, we found that the ABA-independent and ABA-dependent pathways were not completely independent in this study and that ABA-independent stress-responsive genes were also induced by exogenous ABA in at least one stress exposure time point. Comparison of our results with the findings of previous studies showed that plant hormones induce an increase in GSH and ASA levels, possibly by differentially regulating the expression levels of genes encoding ASA–GSH synthesis enzymes. Our results provide the first insights on the molecular mechanism of ABA-induced spring freeze tolerance in wheat.

Toleransi Tanaman Lanskap Terhadap Pencemaran Udara di Kota Sidoarjo

Landscape plants is one of horticultural plants, wich has a few functions, such as for esthetics plant, giving shade on the road, hedges and absorbing air pollution. Judging from its existence, landscape plants are often facing problem, such as clash with air pollution, as a result of the process of photosynthesis on the plants are disrupted. This research is conducted in two locations in the city of Sidoarjo, at the Alun-alun Sidoarjo area as the control location (L0) and Aloha area as the polluted location (L1). Method to determine tolerance level through calculation of APTI (Air Pollution Tolerance Index) with parameters of leaf pH, water content, ascorbic acid and chlorophyll.

Abscisic acid modulates differential physiological and biochemical responses of roots, stems, and leaves in mung bean seedlings to cadmium stress.

Experiments were conducted to determine how exogenous abscisic acid (ABA) mediates the tolerance of plants to cadmium (Cd) exposure. Cd stress strongly reduced all the growth parameters of mung bean seedlings. Cd significantly increased ascorbate peroxidase (APX) and catalase (CAT) activities in roots and stems, and peroxidase (POD) activities in roots, stems, and leaves of mung bean seedlings. Cd caused remarkable increases in the levels of leaf chlorophyll and carotenoid, root polyphenols, and malondialdehyde (MDA) and proline in the three organs. However, Cd greatly decreased leaf CAT activity, root and leaf ascorbic acid (AsA) levels, and stem and leaf polyphenol levels. Foliar application of ABA partially alleviated Cd toxicity on the seedlings. ABA could restore most of the changed biochemical parameters caused by Cd, suggesting that ABA played roles in the protection of membrane lipid peroxidation and the modulation of antioxidative defense systems in response to Cd stress. Our results also implied the differential physiological and biochemical responsive patterns of roots, stems, and leaves to Cd and ABA in mung bean seedlings. The great changes in many biochemical parameters in roots suggested that roots were the first to be affected by Cd and play pivotal roles in response to Cd, especially in chelating Cd and reducing Cd absorption.

Impact of Vermicompost Fertilizer on Spinach Yield and Nutritional Components

Alternative fertilization practices, such the use of vermicompost (VC), have shown great potential to improve both the physical and biological attributes of soils and supplement the nutrient status of soils to improve fertility for vegetable crop production. Modification of soils with coffee vermicompost (CVC) has the potential to improve soil organic content, structure, and microbial activity. Generally, organic fertilizers with slow release nutrient capabilities efficiently use nitrogen and reduce nitrate levels in leafy green vegetables and have been shown to increase ascorbic acid (AA) content. A greenhouse study was conducted over two growing seasons (2011 and 2012) to assess the influence of four CVC rates (0, 25%, 50%, and 75% v/v of soil mix) on Spinacia oleracea growth parameters including fresh leaf weight, leaf area, plant height, leaf number, fresh leaf ascorbic acid (AA) and dry leaf nitrate (DLN). Spinach leaf number and fresh leaf weight increased with CVC rate for both growing seasons and were best described by increasing linear relationships. Surprisingly, spinach AA content remained the same whether DLN content was high or low; and AA and nitrate content were both at highest levels with the 75% v/v CVC treatment in both years. These results indicated that applications of an alternative fertilizer such as CVC can improve spinach yield and that AA content does not always decrease with higher VC application rates, even as nitrate content increases.

Use of Nitric Oxide and Hydrogen Peroxide for Better Yield of Wheat (Triticum aestivum L.) under Water Deficit Conditions: Growth, Osmoregulation, and Antioxidative Defense Mechanism.

The present experiment was carried out to study the influences of exogenously-applied nitric oxide (NO) donor sodium nitroprusside (SNP) and hydrogen peroxide (H2O2) as seed primers on growth and yield in relation with different physio-biochemical parameters, antioxidant activities, and osmolyte accumulation in wheat plants grown under control (100% field capacity) and water stress (60% field capacity) conditions. During soaking, the seeds were covered and kept in completely dark. Drought stress markedly reduced the plant growth, grain yield, leaf photosynthetic pigments, total phenolic content (TPC), total soluble proteins (TSP), leaf water potential (Ψw), leaf turgor potential (Ψp), osmotic potential (Ψs), and leaf relative water content (LRWC), while it increased the activities of enzymatic antioxidants and the accumulation of leaf ascorbic acid (AsA), proline (Pro), glycine betaine (GB), malondialdehyde (MDA), and H2O2. However, seed priming with SNP and H2O2 alone and in combination mitigated the deleterious effects of water stress on growth and yield by improving the Ψw, Ψs, Ψp, photosynthetic pigments, osmolytes accumulation (GB and Pro), TSP, and the antioxidative defense mechanism. Furthermore, the application of NO and H2O2 as seed primers also reduced the accumulation of H2O2 and MDA contents. The effectiveness was treatment-specific and the combined application was also found to be effective. The results revealed that exogenous application of NO and H2O2 was effective in increasing the tolerance of wheat plants under drought stress in terms of growth and grain yield by regulating plant–water relations, the antioxidative defense mechanism, and accumulation of osmolytes, and by reducing the membrane lipid peroxidation.

Roadside air pollution in a tropical city: physiological and biochemical response from trees

BackgroundThe economic growth and social interaction of many developing countries have been enhanced by vehicular transportation. However, this has come with considerable environmental cost. The vehicular emissions of gases such as carbon monoxide (CO), sulphur dioxide (SO2), nitrogen oxide (NOx) and volatile organic compounds (VOC’s) among others are associated with vehicular transportation. The resultant effect can lead to respiratory infections in humans, as well as growth inhibition and death of animals and plants. An investigation was conducted to evaluate the impact of vehicular air pollutants on some selected roadside tree species in the Kumasi Metropolis, Ghana. Ficus platyphylla, Mangifera indica, Polyalthia longifolia and Terminalia catappa, which were abundant and well distributed along the road sides, were selected for the study. Three arterial roads in the Kumasi Metropolis, namely Accra Road (Arterial I), Offinso Road (Arterial II) and Mampong Road (Arterial III), were considered as different traffic volumes experimental sites. The KNUST campus was selected as a control site. Diurnal analysis of CO, NO2, SO2 and VOC was monitored in the sample sites. Three replicates of each tree species were defined at a distance 10 m away from the edge of the road. Physiologically active leaves (20 to 25) from each tree species replicate were harvested for physiological and biochemical determination.ResultsThe ambient air quality data showed higher levels at the arterial road sites, which were severely polluted based on air quality index. The biochemical studies revealed reductions in leaf total chlorophyll and leaf extract pH whilst leaf ascorbic acid and relative water contents increased at the arterial road sites.ConclusionIt was found that the plants’ tolerant response level to vehicular air pollution was in the order T. catappa > F. platyphylla > M. indica and P. longifolia. Based on anticipated performance index, it was revealed that M. indica, F. platyphylla and T. catappa might be performing some level of air cleaning functions along the arterial roads. Whilst P. longifolia was poor and unsuitable as a pollution sink.

Growth and nutrient level of water spinach (Ipomoea aquaticaForssk.) in response to LED light quality in a plant factory

Water spinach (Ipomoea aquatica Forssk.) is widely cultured as an edible green leafy vegetable in Asian countries. Its leaves contain adequate quantities of vitamins, minerals, plant fiber, amino acids, and antioxidant components. It has also been used as a traditional medicine for treating swelling, food poisoning, and antioxidant-related disorders. A plant factory with an artificial lighting system as a fully environment controllable facility has been used for year-round high quantity and quality production of leafy vegetables, herbs, and medicinal plants. This study aimed to investigate the growth and nutrient level in water spinach plants as affected by different LED light qualities in the plant factory. Plants were grown under six light conditions (white, white with far red, blue, red, blue+red, and blue+red with far red), at a PPFD of 200 µmol m(-2) s(-1) for 3 weeks after transplanting. The highest shoot weight, root biomass production, total leaf area, side-shoot development, and ascorbic acid content in shoot were observed in blue light treatment. Different light qualities influenced biomass distributions in plant leaf and stem. Red light increased plant stem length and stem dry mass with a decrease in leaf dry mass. Higher blue ratio (>50%) lights enhanced antioxidant activity in plant shoots, mainly due to a significant increase in stem rather than in leaves.

Urate-lowering effect of Manilkara zapota aqueous leaf extracts in a murine model of hyperuricemia

Background: Hyperuricemia and diseases related to hyperuricemia have been recognized among Filipinos in different countries. Diseases related to hyperuricemia such as gout and increased risks of cardiovascular diseases have given an avenue for methods on lowering uric acid levels. Aims and Objectives: Manilkara zapota, commonly known as Chico, has been reported to have the potential to reduce the uric acid level and thus was tested using aqueous leaf extracts of the plant. Materials and Methods: The plant was administered at a low dose of 1g/kg body weight (BW) and a high dose of 3g/kg BW on 10–16-week-old male ICR mice for 28 days. Three control groups were used for comparison of results: The sham group was administered with sterile distilled water and was not treated with KBrO3, a positive control group was administered with ascorbic acid instead of the leaf extract and was treated with KBrO3, and a negative control group was administered with sterile water and was also treated with KBrO3. Hyperuricemia was induced using KBrO3 on the last day to detect for uric acid lowering activity. Results: Analysis shows that the negative control group had the highest mean of uric acid levels after hyperuricemia induction resulting to a significant difference from among the other groups. The mean uric acid levels of the groups treated with the leaf extract and ascorbic acid after hyperuricemia induction did not have any significant difference from each other. Conclusion: There is a urate-lowering activity from Manilkara zapota aqueous leaf extracts that are possibly due to the presence of flavonoids.

Lettuce (Lactuca sativa L.) growth, yield and quality response to nitrogen fertilization in a non-circulating hydroponic system

ABSTRACTThe objective of this study was to determine the effect of nitrogen fertilization rate on growth and quality of leafy lettuce grown during the winter season in non-circulating hydroponic system. Plants were subjected to seven nitrogen (N) concentrations, i.e. 0, 30, 60, 90, 120, 150 and 180 mg L−1 N using ammonium nitrate. Nitrogen treatments did not have a significant effect on leaf fresh and dry mass, root fresh and dry mass, number leaves and leaf area. Leaf ascorbic acid and total phenolic content, and antioxidant capacity peaked at 100 and 120 mg L−1 N, whereas leaf chlorophyll concentration linearly increased with increasing N application. The results indicate that a solution N concentration of 100 and 120 mg L−1 may be sufficient to improve growth, yield and quality parameters of leafy lettuce grown in non-circulating hydroponic system.

PAHs accumulation on leaves of six evergreen urban shrubs: A field experiment

Air pollution refers to the occurrence of toxic substances in the atmosphere which results in detrimental effects to human beings and living environments. Among the most common atmospheric pollutants, Polycyclic Aromatic Compounds (PAHs) are the most common substances originated by vehicles. The aim of the study was to investigate the accumulation of 16 PAHs in leaves of six evergreen shrubs frequently used in Italy for urban landscaping (Elaeagnus x ebbingei, Ilex aquifolium, Laurus nobilis, Ligustrum japonicum, Photinia x fraserii and Viburnum lucidum). The study was conducted in two sites: a public park and a high traffic square. Six samplings were performed in a period of 26 months during Winter. The plants tolerance was investigated considering leaf-extract pH, total chlorophyll, leaf ascorbic acid content and relative leaf water content. A morphological leaf characterization was also carried out considering stomatal density and cuticle width. Phenanthrene, fluoranthene, fluorene and pyrene were the major compounds yielded in the plant leaves accounting for about 83% of ΣPAHs, the contributions being 53%, 11.3%, 10.5% and 8.5%, respectively. Such compounds are related to vehicular emissions. The analysis of the PHAs accumulation and the evaluation of the plants tolerance also revealed that the efficiency in trapping 5- and 6-rings potentially carcinogenic PAHs such as benzo(b)fluoranthene, benzo(k)fluoranthene in plant leaves is highest for Elaeagnus x ebbingei, L. japonicum and L. nobilis while Elaeagnus x ebbingei and Photinia x fraserii resulted to be those most tolerant to air pollution. The role of plants in mitigating traffic pollution is confirmed.

Leaf Dust Accumulation and Air Pollution Tolerance Indices of Three Plant Species Exposed to Urban Particulate Matter Pollution from a Fertilizer Factory

Leaf Dust Accumulation and Air Pollution Tolerance Indices of Three Plant Species Exposed to Urban Particulate Matter Pollution from a Fertilizer Factory To assess the dust interception efficiency and air pollution tolerance index (APTI) of three plant species Cyperus alopecuroides, Pluchea dioscoridis and Ricinus communis near fertilize factory in Abo-Zabaal village (Egypt) the present study was undertaken. The air quality has been measured and air pollution index was calculated for the different sites. Also relative water content, total chlorophyll, leaf extract pH and ascorbic acid content were measured. The highest dust deposition was detected in Pluchea dioscoridis (0.29) and Ricinus communis (0.19) and the values were slightly higher in winter than in summer. The APTI highest values were observed in R. communis (25.3) and the lowest ones were recorded in C. alopecuroides (12.16) and the values were slightly higher in summer than in winter. Thus plants can be used to intercept dust particles which are of potential health hazards to humans..

Chemical and Natural Plant Extract in Ameliorating Negative Impact of Tropospheric Ozone on Wheat Crop: A Case Study in a Part of Semiarid North West India

ABSTRACTCurrent rise in concentration of tropospheric ozone (O3) has deleterious effect on growth and yield of crops. Wheat is one of the most O3 sensitive crops. Application of Chemical antioxidants may be beneficial to lessen the harmful effects of O3 on crops. A two year study growing wheat (variety PBW550) was carried at the farms of Indian Agricultural Research Institute, New Delhi in 2010–11 and 2011–12 to evaluate the efficacy of some natural and environment friendly antioxidant chemicals in ameliorating the negative impacts of elevated ozone on growth and productivity of wheat. The treatments were i) charcoal filtered air (CF) ii) 1% ascorbic acid (AA), iii) 100 ppm quercetin (Q), iv) 10% marigold leaves extract (Tagetes patula var pusa arpita) (T) and v) elevated O3 control (C). Additional 25–35 ppb of O3 over the ambient levels was maintained in all open top chambers except the CF treatment. The seasonal daily average O3 concentration in ambient air was 38 ppb in 2010–11 and 29 ppb in 2011–12 during the crop growth period. The exogenous application of antioxidants increased the levels of endogenous leaf ascorbic acid. The activity of antioxidant enzymes (superoxide dismutase, catalase and peroxidase) was lowered by 5 to 34% in antioxidants sprayed plants as compared to elevated O3 control (C). The application of antioxidants increased the yield of wheat by 23–26% in AA, 13–15% in Q and 8–10% in T as compared to C. The micronutrient (Cu, Fe, Zn and Mn) content of wheat grains on application of exogenous ascorbic acid was higher. The application of antioxidant chemicals was effective in alleviating the negative impacts of elevated O3 on enzyme activity and nutritional quality of wheat which increased the growth and yield of the crop

Manipulation of the rice L-galactose pathway: evaluation of the effects of transgene overexpression on ascorbate accumulation and abiotic stress tolerance.

Ascorbic acid (AsA) is the most abundant water-soluble antioxidant in plants, and it plays a crucial role in plant growth, development and abiotic stress tolerance. In the present study, six key Arabidopsis or rapeseed genes involved in AsA biosynthesis were constitutively overexpressed in an elite Japonica rice cultivar. These genes encoded the GDP-mannose pyrophosphorylase (GMP), GDP-mannose-3',5'-epimerase (GME), GDP-L-galactose phosphorylase (GGP), L-galactose-1-phosphate phosphatase (GPP), L-galactose dehydrogenase (GDH), and L-galactono-1,4-lactone dehydrogenase (GalLDH). The effects of transgene expression on rice leaf AsA accumulation were carefully evaluated. In homozygous transgenic seedlings, AtGGP transgenic lines had the highest AsA contents (2.55-fold greater than the empty vector transgenic control), followed by the AtGME and AtGDH transgenic lines. Moreover, with the exception of the AtGPP lines, the increased AsA content also provoked an increase in the redox state (AsA/DHA ratio). To evaluate salt tolerance, AtGGP and AtGME transgenic seedlings were exposed to salt stress for one week. The relative plant height, root length and fresh weight growth rates were significantly higher for the transgenic lines compared with the control plants. Altogether, our results suggest that GGP may be a key rate-limiting step in rice AsA biosynthesis, and the plants with elevated AsA contents demonstrated enhanced tolerance for salt stress.