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1.
Nitrogen-efficient rice cultivars can reduce nitrate pollution   总被引:3,自引:1,他引:2  

Introduction  

Environmental pollution by un-utilized nitrogenous fertilizer at the agricultural field is one of the key issues of the day. Rice-based cropping system, the mainstay of Indian agriculture, is one of the main sources of unused N-fertilizer since rice utilizes only 30–40% of total applied N, and the rest goes to waste and creates environmental as well as economic loss.  相似文献   

2.
Environmental Science and Pollution Research - In recent years, ornamental plants have come under investigation as phytoremediation agents. In addition to reducing contaminant concentrations in...  相似文献   

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4.
Phytoremediation appears to be a promising technique for metal soil clean up, although its successful application on a large scale still remains a challenge. Field experiments for six scented Pelargonium cultivars, conducted on two Pb-contaminated calcareous and acidic soils, revealed vigorous plant growth, with no symptoms of morpho-phytotoxicity in spite of high Pb accumulation levels. Lead contents in the harvestable parts of all plants grown on the acidic and more contaminated soil were significantly higher than those grown on the calcareous soil. Three cultivars (Attar of Roses, Clorinda and Atomic Snowflake) are Pb-hyperaccumulator plants: they accumulated more than 1000 mg Pb kg−1 DW, with high biomass produced.  相似文献   

5.
In order to evaluate the ideal time of herbicide applications to desiccate soybean cultivars with determinate and indeterminate growth habits in preharvest, an experiment was carried out at the University of Ponta Grossa (PR), during 2002--2003. The experimental design used was a randomized blocks arranged in a factorial scheme 4 x 5 (herbicides and time of application), with three replications, using four soybean cultivars: Spring, V-Max, BR-16, and BRS-133. The herbicides glufosinate, diquat, and paraquat were used at the rate of 400 g ha(-1), when soybean was at stage of R6.0, R6.5, R7.0, R7.5, and R8.0. The assessments included yield, as well as yield components, considering each cultivar separately. The results show that desiccation should be done on cultivars with determinate growth habit at stages between R7.0 and R7.5, independent of herbicide used. For indeterminate growth habit cultivars, desiccation should be done later, because those pods formed after R6.5 stage are important to define yield; although herbicides have different mode of action, yield results were similar. In cultivars, desiccation should start when all pods in the middle of plants become yellow and grains are not held by fibers.  相似文献   

6.
The present experiment was aimed at assessing the impact of simulated acidic precipitation (SAR) on growth, biomass accumulation and yield of two cultivars of wheat (Triticum aestivum L.), Malviya 206 and 234, varying in cuticular thickness and leaf area. Wheat cultivars were exposed to simulated rain acidified to pH 5.6 (control), 5.0, 4.5, 4.0 and 3.0 from 30 days of age, twice a week for five weeks. The plants received ambient precipitation of unknown acidity, as well as the acid rain treatments. Growth parameters such as shoot height, root length, and leaf area were reduced significantly in treated plants at different growth stages. Above and below-ground biomass also decreased significantly in the plants treated with acidic precipitation. Relative to control, the number of grains per plant and yield per m(2) declined significantly at all SAR treatments. The hypothesis that the variety with thinner cuticle and greater leaf area would be more susceptible to acidic precipitation was not supported by the present study.  相似文献   

7.
Abstract

Wheat (Triticum aestivum L.) seedlings grown from seeds produced in “organic”; (non‐chemical) and “conventional”; cropping systems are characterized by a) similar rates of root and shoot growth, b) equal sensitivity to phytotoxicity by the herbicide glyphosate, and c) equivalent basal activity of the enzyme glutathione S‐transferase (both in the roots and in the shoots). In addition, treatment of these seedlings with glyphosate leads to significantly higher contents of this enzyme both in the shoots and in the roots. However, time‐course and dose‐response investigations indicate significant differences in the induction pattern of glutathione S‐transferase: the response of “conventional”; wheat seedlings takes place earlier and with higher efficiency, than that of the “organic”; ones.  相似文献   

8.
The effects of a mixture of SO(2) and NO(2) at a concentration of 0.08 to 0.10 ppm (in microg m(-3): 164-205 for NO(2); 229-286 for SO(2)) were tested for four weeks on two old varieties of winter wheat, Little Joss and Holdfast, introduced in 1908 and 1938, respectively, grown in simulated autumn conditions. After two weeks, root dry weights of both varieties were significantly decreased but, although there was some leaf necrosis, shoot dry weights were unaltered. After a further two weeks, the dry weights of the shoots as well as the roots were significantly decreased. These effects, amounting to a combined 40% decrease in total dry weight, were greater than those in identical experiments carried out with the present day variety Avalon, in which the decrease was 20%. The results suggest that the modern cultivar Avalon is more tolerant of SO(2) and NO(2) than Little Joss and Holdfast, which were grown many years ago.  相似文献   

9.
Cadmium (Cd) stress may cause serious physiological, ultramorphological and biochemical anomalies in plants. Cd-induced physiological, subcellular and metabolic alterations in two transgenic cotton cultivars (BR001, GK30) and their parent line (Coker 312) were evaluated using 10, 100 and 1000 μM Cd. Germination, fresh biomass of roots, stems and leaves were significantly inhibited at 1000 μM Cd. Root volume tolerance index significantly increased (124.16%) in Coker 312 at 1000 μM Cd. In non-Cd stressed conditions, electron micrographs showed well-configured root meristem and leaf mesophyll cells. At 1000 μM Cd, greater ultramorphological alterations were observed in BR001 followed by GK30 and Coker 312. These changes were observed in nucleus, vacuoles, mitochondria and chloroplast. Dense precipitates, probably Cd, were seen in vacuoles, which were also attached to the cell walls. A considerable increase in number of nuclei, vacuoles, starch granules and plastoglobuli was observed in the electron micrographs of both roots and leaves at 1000 μM Cd. MDA contents were higher in roots of BR001 at 1000 μM Cd. Mean values of SOD activity in leaves of both BR001 and GK30 at 1000 μM Cd significantly increased as compared to the controls. POD activity in roots of BR001 and Coker 312 was greater at all Cd (10, 100, 1000 μM) levels over the control. Regarding APX, highest percent increase (71.64%) in roots of GK30 at 1000 μM Cd was found. Non-significant differences in CAT activity were observed at all levels of Cd stress in leaves of BR001 and GK30. Both transgenic cotton cultivars and their parental line invariably responded towards Cd stress. However, Coker 312 showed Cd-resistant behavior as compared to its progeny lines (BR001 and GK30).  相似文献   

10.
Intraspecific variation in six cultivars of clover Trifolium alexandrinum L., (Bundel, Wardan, JHB-146, Saidi, Fahli, and Mescavi) has been studied with ambient and elevated O3 (ambient?+?10 ppb O3) in open top chambers. Significant effect of elevated O3 was detected on different morphological, physiological, and biochemical parameters depicting differential response among the test cultivars. Results showed that the magnitude of O3 induced foliar injury symptoms varied in all the cultivars. Ozone significantly depressed photosynthetic rate, stomatal conductance, and photosynthetic efficiency, although variations were cultivar specific. Ozone treatment diminished total biomass of all the cultivars; reduction was highest in Wardan with least O3 resistance followed by Bundel, JHB-146, Saidi, Mescavi, and Fahli. According to the cumulative sensitive index, variations in the sensitivity showed that two cultivars (Wardan and Bundel) were sensitive to elevated O3, while other three cultivars (Fahli, Saidi, and Mescavi) were resistant, and JHB-146 showed intermediate sensitivity. Therefore, the present study supported the selection of sensitive cultivar of clover as a bioindicator for O3 under Indian conditions for the areas experiencing higher concentrations of O3.  相似文献   

11.
Net photosynthesis (Pn) and mean stomatal conductance (gs) of soybean (Glycine max (M.) L.) cvs 'Dare', 'Essex' and 'Williams 82' were inhibited by exposure to 200 nliters liter(-1) ozone (O(3)) for 4 h. Changes in gas exchange rates were not uniform over time, and a near steady state condition was attained after fumigation for 2 h. There was no recovery of Pn or gs for up to 2 h following termination of O(3) application. The cv 'Dare' was considered most sensitive to O(3) since, in this cultivar, gs was least responsive during the initial 2.5 h of fumigation and the estimated internal O(3) flux was about 10% greater than in the other cultivars. Polyacrylamide gel electrophoresis of soybean leaf extracts, followed by activity staining for superoxide dismutase (SOD), revealed the presence of numerous major and minor bands. Cynide sensitivity of several isoforms indicated the presence of both Cu-Zn and Mn SODs. In cv 'Essex', each metalloform accounted for 50% of the total SOD activity. No qualitative differences in SOD banding patterns were evident among the three soybean cultivars before or after O(3) treatment. Ozone fumigation for 4 h did not significantly alter SOD activity in any cultivar. The contribution of gs, as a flux limitation, and SOD activity are discussed as tolerance mechanisms to O(3) in soybean.  相似文献   

12.
Hasan SA  Hayat S  Ahmad A 《Chemosphere》2011,84(10):1446-1451
The present study was conducted with an aim to gain better insight of brassinosteroid generated response on the effects of cadmium on photosynthetic machinery and active oxygen metabolism in two tomato cultivars (K-25 and Sarvodya). These tomato cultivars were subjected to graded cadmium levels in soil (0, 3, 6, 9 or 12 mg kg−1 soil) with their foliage being sprayed with 0 or 10−8 M of 28-homobrassinolide/24-epibrassinolide (HBL/EBL) at 59 d stage. The results suggested that photosynthetic parameters, leaf water potential and activity of several enzymes (nitrate reductase and carbonic anhydrase) decreased significantly in both the cultivars, to a lesser extent in K-25 than Sarvodya with the increasing levels of cadmium in the soil. However, the activity of antioxidant enzymes and proline content increased in response to metal treatment as well as the application of brassinosteroids (HBL/EBL). Overall, exogenous application of brassinosteroids improved the activity of photosynthetic machinery and that of antioxidant defense system in both the cultivars, and also nullified the damaging effect of metal on these parameters.  相似文献   

13.
The effects of the photochemical oxidant air pollutant ozone (O(3)) on growth and yield of three garden crops, broccoli (Brassica oleracea L.), lettuce (Lactuca sativa L.), and onion (Allium cepa L.) were studied in an open-top chamber experiment conducted in the field in southern California. Four cultivars each of leaf lettuce, broccoli, and globe onion were exposed to charcoal-filtered air (CF), non-filtered (NF) air, or NF plus 1.5 times ambient O(3) concentration from 4 weeks after germination in January or February until harvest. Exposures lasted 31 days for lettuce, 55 to 78 days for broccoli, and 105 days for onion. Results showed that despite severe O(3) injury to outer leaves, lettuce yields were not affected by O(3). Broccoli also was resistant to O(3) and no growth reduction was observed at ambient O(3) concentrations. Onions were more susceptible to O(3), but only one cv. 'Rio Bravo' had significant yield losses (ca. 5%) at ambient O(3) levels. These results suggest that, in general, concentrations of O(3) in the winter and spring may be below the threshold for adverse effects on yields of broccoli, lettuce and onion.  相似文献   

14.
Soybean [Glycine max (L.) Merr.] cultivars Essex and Forrest that exhibit differences in ozone (O(3)) sensitivity were used in greenhouse experiments to investigate the role of leaf extracellular antioxidants in O(3) injury responses. Charcoal-filtered air and elevated O(3) conditions were used to assess genetic, leaf age, and O(3) effects. In both cultivars, the extracellular ascorbate pool consisted of 80-98% dehydroascorbic acid, the oxidized form of ascorbic acid (AA) that is not an antioxidant. For all combinations of genotype and O(3) treatments, extracellular AA levels were low (1-30nmolg(-1) FW) and represented 3-30% of the total antioxidant capacity. Total extracellular antioxidant capacity was twofold greater in Essex compared with Forrest, consistent with greater O(3) tolerance of Essex. The results suggest that extracellular antioxidant metabolites in addition to ascorbate contribute to detoxification of O(3) in soybean leaves and possibly affect plant sensitivity to O(3) injury.  相似文献   

15.
Samantary S 《Chemosphere》2002,47(10):1065-1072
Biochemical investigations were carried out in Cr-tolerant and Cr-sensitive cultivars of mung bean (Vigna radiata L.) with different concentrations of hexavalent chromium (as K2Cr2O7) in hydroponics culture. Seeds were germinated and grown in the presence or absence of chromium under controlled environmental conditions. Protein, pigment and enzyme analysis were conducted in both Cr-tolerant and Cr-sensitive cultivars of mung bean after 72 h of treatments. Chlorophyll and protein contents were reduced in Cr-sensitive cultivars more than those of the tolerant ones. The enzyme activity varied among the Cr-tolerant and Cr-sensitive ones. Activities of catalase, peroxidase, glucose-6-phosphate dehydrogenase and superoxide dismutase were greater in Cr-sensitive than tolerant cultivars.  相似文献   

16.
The sensitivity to ozone of ten Bangladeshi wheat cultivars was tested by exposing plants to eight ozone exposure regimes (50, 60, 80, 100, 120, 135, 150, and 200 ppb for 14, 11, 8, 6, 5, 4, 3, and 1 days, respectively, for 8 h/day) in controlled environment chambers. Visible leaf injury, dry weight, chlorophyll, carotenoid content, leaf greenness (SPAD value), quantum yield of photosynthesis, and stomatal resistance were measured to evaluate response. Shoot biomass, total chlorophyll, leaf greenness, and carotenoid content were reduced in ozone-exposed plants. Based on the results of principal component analysis (PCA)-biplot analysis, the order of sensitivity to ozone was: Akbar?>>?Sufi?≥?Bijoy?≥?Shatabdi?>?Bari-26?≥?Gourab?>?Bari-25?≥?Prodip?≥?Sourav?>>?Kanchan. The most important parameters to discriminate cultivars with respect to ozone sensitivity were visible injury and chlorophyll b/a ratio, whereas quantum yield of photosynthesis was less important. Differences in stomatal resistance were not a significant factor in ozone response. Regression of cultivars’ PCA scores against year of release revealed no trend, suggesting that ozone tolerance was not incorporated during cultivar breeding.  相似文献   

17.
Field studies were conducted at USDA Beltsville Agricultural Research Center, Beltsville, Maryland, in 1984 and 1985 using open-top chambers to acquire information on the responses of 12 soybean (Glycine max L. Merr.) cultivars to O3 stress and to examine the interactions between maturity groups and O3 stress. Cultivars representing Groups III, IV, and V were exposed for approximately 3 months to charcoal-filtered air (CF) and nonfiltered air plus 40 nl litre(-1) O3 (NF + O3). Ozone was added 6 h d(-1), 5 d week(-1) for 13 weeks. The CF effectively reduced the accumulative oxidant exposure (AOX) to less than 1.0 microl litre(-1) h and the NF + O3 treatment approximately doubled the ambient AOX (16.7 microl litre(-1) h) to about 30 microl litre(-1) h. The AOX estimates the total O3 exposure above 30 nl litre(-1) during an entire growing season. Plant growth rates and relative growth rates were reduced by 17.0 and 14.4%, respectively, when averaged over cultivars. Based on growth rates, the Group III cultivars were the most affected by O3 stress. Averaged over cultivars, leaf expansion rates, leaf conductance, and transpiration rates were lower in the NF + O3 treatment compared to the CF control; however, wide variation was found with the stomatal results from field observations. Combined over years and cultivars, grain yield was reduced by an average of 12.5% by O3 stress with 3 of 12 cultivars showing significant reductions. Grain protein content was increased by 0.7% by O3 stress, but cultivar differences were equal to the differences caused by the O3 treatments. Grain oil content was unchanged by the O3 treatments. Group IV cultivars showed the greatest decrease in grain yield due to O3 stress. Multiple regression analyses were calculated using the difference between the CF and NF + O3 treatment as a measure of O3 stress. Significant positive relationships were found among net assimilation rates, plant growth rates, relative growth rates, and leaf expansion rates, which suggest that growth analysis characteristics would be useful in addition to yield in air pollution tolerance improvement studies with soybeans.  相似文献   

18.
Environmental Science and Pollution Research - Nowadays, public concerns regarding deleterious effect of lead (Pb) is on rise due to its abundance and toxic effect on plants and other living...  相似文献   

19.
The antiozonant EDU (ethylenediurea) was used to assess the impact of ambient O3 under field conditions on five cultivars of tropical wheat (Triticum aestivum L.). EDU solution (0 ppm and 400 ppm) was applied as soil drench (100 ml plant?1) 10 days after germination (DAG) at an interval of 12 days. EDU-treated plants showed significant increments in stomatal conductance, photosynthetic rate, variable fluorescence, total chlorophyll, ascorbic acid, proline and protein contents and protective enzymes (POX, SOD and APX) activities in HUW468, HUW510 and HUW234 cultivars, while, a reverse trend was observed for lipid peroxidation. EDU application restored grain yield significantly by maintaining higher levels of antioxidants, metabolites and enzymes in cultivars HUW468 and HUW510. Sonalika and PBW343 showed least response of measured parameters under EDU treatment suggesting their greater resistance to O3. EDU, thus proved its usefulness in screening suitable wheat cultivars for areas experiencing elevated concentrations of O3.  相似文献   

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