首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The effects of selenium (Se) (VI) soil fertilization with 2 μg Se L?1 or foliar spraying twice with 20 mg Se L?1 in the form of sodium (Na) selenate on the physiological and biochemical characteristics of cabbage plants were studied. The ability of the plants to take up Se and translocate it to different parts of the plants was also studied. Despite the high concentration of Se in the foliar solution, there was no effect on photosynthesis, transpiration rate, photochemical efficiency of PSII, or electron transport system activity. The amount of chlorophyll and anthocyanins were unchanged. At harvest, the concentration of Se in control plants was lower than 100 ng Se g?1 dry weight (DW), while plants treated with 20 mg Se L?1 contained 5500 ng Se g?1. Selenium enriched cabbage could be used in human nutrition. The tolerance of cabbage to Se could be explained by the formation of insoluble compounds that are not available for the plant.  相似文献   

2.
The effects of selenium (Se) cadmium (Cd) interactions on plant growth and metabolism are not fully clear. In the present study, we assessed whether Se could alleviate the toxic effects of Cd on growth and metabolism of maize. Seeds of maize variety FH-985 were sown in pots filled with sand treated with CdCl2 (0, 50 and 100 µM) and Se (0, 2 and 4 mg L?1) through Hoagland’s nutrient solution. Low Se (2 mg L?1) increased germination percentage and rate, while high Se (4 mg L?1) increased fresh and dry biomass under Cd stress. Interestingly, all Se concentrations were effective in alleviating the toxic effects of Cd on photosynthetic pigments, whereas higher Se mitigated the Cd-induced oxidative stress and increased flavonoids both in the shoots and roots while phenolics in the roots. The results demonstrated that root zone Se altered tissue-specific primary metabolism in maize. Furthermore, low Se mitigated the Cd-induced decrease in total proteins in the root. Overall, Se-mediated decrease in the oxidative stress in the shoots while increase of secondary metabolites in the roots helped the plants to grow faster at early growth stage and caused increase in the biomass under different Cd regimes.  相似文献   

3.
In a greenhouse experiment, wheat cultivars PDW 291, PBW 550, and TL 2908 were grown in alkaline sandy-loam soil treated with sodium selenate at 0, 2, and 4 mg selenium (Se) kg?1 soil. Selenate-treated wheat plants accumulated greater Se in roots, stems, leaves, and grains and showed growth retardation, snow-white chlorosis, decreased shoot length and chlorophyll, and reduced leaf area and produced less number of grains as compared to control plants. Maximum reduction in these parameters was observed in selenate-treated TL 2908 plants and most of the plants died before maturity with almost no grain formation with 4 mg Se kg?1 soil. Selenium accumulation resulted in decreased reducing sugar, starch, and protein contents in grains whereas total free amino acids increased significantly in all the three cultivars. Selenium accumulation in wheat showed metabolic disturbances and its accumulation in grains was beyond toxic levels, thus making it unfit for consumption.  相似文献   

4.
Terminal drought stress (drought at reproductive growth stage) has been considered a severe environmental threat under changing climatic scenarios and undoubtedly inhibits sunflower production. A field study was conducted to explore the potential role of foliar applied boron (B) (0, 15, 30, 45 mg L?1) at late growth periods of sunflower in alleviating the adversities of terminal drought stress (75, 64, 53 mm DI) grown from inflorescence emergence to maturity stages. The plant water relations such as leaf relative water content (RWC), water potential (Ψw), osmotic potential (Ψs), and turgor pressure (Ψp) were increased significantly with B foliar sprays while exposed to terminal drought stress. Foliar B application considerably improved the nitrogen and B concentrations in leaf and seed tissues, and also chlorophyll a and b pigments under terminal drought stress conditions. Drought-induced proline accumulation prevented the damages caused by drought stress, nevertheless, B foliar spray increased its contents. Compared to well-watered conditions, terminal drought stress substantially declined the growth performance in terms of reduced leaf area index (LAI), crop growth rate (CGR), net assimilation rate (NAR), and total dry matter (TDM) production; however, foliar B supply (30 mg L?1) might be helpful for improving drought tolerance in sunflower with reduced growth losses.  相似文献   

5.
Selenium (Se) is an essential element for humans but is not considered as essential for plants. However, its beneficial role in improving plant growth and stress tolerances is well established. In order to study the role of Se in cadmium (Cd) toxicity in pepper (Capsicum frutescens cv. Suryankhi Cluster), this experiment was carried out in greenhouse conditions. Treatments comprised Cd [0, 0.25, and 0.5 mM cadmium chloride (CdCl2)] and Se [0, 3, and 7 µM sodium selenite (Na2SeO3)] with three replications. The result showed that Cd decreased chlorophyll a, chlorophyll b, and carotenoids, whereas Se supplementation diminished Cd toxicity on photosynthetic pigment. Selenium at 7 µM significantly increased the leaf area in the plants grown at 0.25 mM Cd. The application of Se at 3 µM with 0.25 mM Cd and Se at 3 µM and Se at 7 µM with 0.5 mM Cd increased the activity of catalase (CAT). Selenium at 7 µM decreased the proline content of pepper leaves exposed to Cd at 0.5 mM (30%). Selenium significantly enhanced the antioxidant activity of leaves, which was diminished by Cd toxicity. In general, Se has a beneficial effect on plant growth and is an antioxidant enzyme of pepper cv. Suryankhi Cluster under Cd stress and non-stress conditions.  相似文献   

6.
This study was conducted to evaluate the roles of glycine betaine (GB) in mitigating deleterious effect of salt stress on lettuce. Lettuce plants were subjected to two salinity (0 and 100 mmol l?1 NaCl) and four GB levels (0, 5, 10, 25 mmol l?1). Salinity resulted in a remarkable decrease in growth parameters, relative leaf water content and stomatal conductance. Plants subjected to salt stress exhibited an increase in membrane permeability (MP), lipid peroxidation (MDA), leaf chlorophyll reading value, H2O2 and sugar content. Exogenous foliar applications of GB reduced MP, MDA and H2O2 content in salt-stressed lettuce plants. Salt stress increased Na and generally decreased other nutrient elements. GB reduced Na accumulation, but significantly increased other element contents under salinity conditions. The study showed that gibberellic acid (GA) and salicylic acid (SA) content in salt-stressed plants were lower than those of nonstressed plants. However, salinity conditions generally increased the abscisic acid content. GB treatments elevated the concentrations of GA, SA and indole acetic acid (IAA) at especially 10 and 25 mmol l?1 GB under salt stress conditions. It could be concluded that exogenous GB applications could ameliorate the harmful effects of salt stress in lettuce.  相似文献   

7.
In vitro, applications of nanosilicon dioxide (SiO2) and chitosan were investigated for their effects on growth and proliferation of apple (Malus domestica Borkh. ‘Gala’) explants under osmotic stress induced by agar to simulate drought stress and under non-stressed conditions. The experiment included five levels of SiO2 (0, 25, 50, 100, and 200 mg L?1), two levels of chitosan (0 and 40 mg L?1), and two levels of agar (7 g L?1 and 9 g L?1) added to Murashige and Skoog medium. Under non-stressed conditions (7 g L?1 agar), application of SiO2 at 50 or 100 mg ?1 increased proliferation of apple explants. Use of 50 or 100 mg L?1 SiO2 or 40 mg L?1 chitosan increased growth of apple explants under osmotic stress (9 g L?1 agar). This research suggests that use of SiO2 or chitosan may improve plant growth and tolerance to stress.  相似文献   

8.
Influence of drought and salt stress on different morphological and physiological growth parameters in Capsicum annuum inoculated with our isolates was estimated during the present study. Bulkhorderia cepacia was reported to possess the maximal, whereas Citrobacter feurendii the least plant growth promoting efficacy under salt and drought stress. ACC Deaminase activity of purified B. cepacia, C. feurendii and Serratia marcescens was 12.8 ± 0.44, 12.3 ± 0.56 and 11.7 ± 0.53 μM αKB mg?1 min?1 respectively. Under drought stress, B. cepacia showed maximum tolerance as it produced 4.893 ± 0.06 mg/mg protein of exopolysaccharide followed by C. feurendii and S. marcescens that produced 4.23 ± 0.03 and 3.46 ± 0.05 mg/mg protein, respectively. Chlorophyll “a” concentration was recorded 5.7 gm L?1 in B. cepacia inoculated plant (without stress) and was sustained till 2.9 gm L?1 even under the highest tested drought period. Chlorophyll “a” concentration in the B. cepacia inoculated plant under the highest tested NaCl concentration was 3.2 gm L?1. Thus, bacterial inoculation mitigates the effects of salinity by the proliferation of root system, increasing plant biomass proving to be potential bioinoculum for alleviating abiotic stress.  相似文献   

9.
Interactions between Zn and Cd on the accumulation of these metals in coontail, Ceratophyllum demersum were studied at different metal concentrations. Plants were grown in nutrient solution containing Cd (0.05–0.25 mg l?1) and Zn (0.5–5 mgl?1). High concentrations of Zn caused a significant decrease in Cd accumulation. In general, adding Cd solution decreased Zn accumulation in C. demersum except at the lowest concentration of Zn in which the Zn accumulation was similar to that without Cd. C. demersum could accumulate high concentrations of both Cd and Zn. The influence of humic acid (HA) on Cd and Zn accumulation was also studied. HA had a significant effect on Zn accumulation in plants. 2 mg l?1 of HA reduced Zn accumulation at 1 mg l?1 level (from 2,167 to 803 mg kg?1). Cd uptake by plant tissue, toxicity symptoms and accumulation at 0.25 and 0.5 mg l?1, were reduced (from 515 to 154 mg kg?1 and from 816 to 305 mg kg?1, respectively) by addition of 2 mg l?1 of HA. Cd uptake reached a maximum on day 9 of treatment, while that of Zn was observed on day 15. Long-term accumulation study revealed that HA reduced toxicity and accumulation of heavy metals.  相似文献   

10.
Selenium (Se) is an essential nutrient for animals, humans, and microorganisms, but its role in the plants needs further exploration. It is considered beneficial at low levels, but is toxic at higher levels, and there is a fine boundary between these concentrations. Generally, Se levels less than 1 mg kg?1 have been found to be beneficial for the plants while higher levels cause toxicity in most of the agricultural crops. At low concentrations, Se can act as a plant growth regulator, antioxidant, anti-senescent, abiotic stress modulator, and defensive molecule against pathogens in plants. At higher concentrations, plants show various toxic symptoms, which include stunting of growth, chlorosis, withering, and drying of leaves, decreased protein synthesis premature and even death of the plant. The roles of selenium as enhancer and inhibitor of plant growth in various agricultural crops are discussed here with recent updates. Biofortification of some crops with Se using agronomic and genetic approaches is being explored to cultivate them in the regions having Se-deficiency in foods. Strategies of phytoremediation of Se in hyperaccumulators and transgenic plants overexpressing enzyme/proteins to increase Se tolerance are also described.  相似文献   

11.
Abstract

In this research the effect of foliar application of selenium (Se) at four levels (Na2OSe4; 0, 5, 10 and 20?mg L?1) was evaluated on some phytochemical characteristics of Sultana grapevine under different salinity levels (NaCl; 0 or 75?mM). The vines were fed twice a week with Hoagland nutrient solution and Se was foliar applied twice with 24 intervals. During growing period, plant height, leaf number and leaf area were recorded. Moreover, at the end of experiment, mature leaves from middle nods of canes were used for measurement of some phytochemical indices. According to results, Se application had a positive effect on plant height, leaf numbers, leaf area and photosynthetic pigments content especially at 5?mg L?1 and to some extent 10?mg L?1 Se levels. Under salinity stress, foliar application of Se at 5?mg L?1 considerably decreased vines leaves electrolyte leakage and lipid peroxidation values compared to non se-treated plants under salinity stress condition. Selenium had an additive effect on salinity stress (75?mM NaCl) induced accumulation of total phenol, total flavonoid, soluble sugars and proline content in leave of vines. Moreover, the interaction of salinity and Se at 5 and 10?mg L?1 improved leaves antioxidant enzymes activities in Sultana grapevine. Likewise, foliar application of Se improved leaf mineral content in 75?mM NaCl -treated vines. Totally, foliar application of selenium (Se at 5 or 10?mg L?1) increased salt tolerance through improvement in nutritional balance and by enzymatic and non-enzymatic antioxidant capacity in grapevine leaves.  相似文献   

12.
A pot experiment was conducted in a greenhouse to evaluate the effect of drought stress on growth and turf quality of 24 accessions of crested wheatgrass (Agropyron cristatum (L.) Gaertner.) and ‘Rembrandt’ tall fescue, and to find the most drought-tolerant accession(s) of crested wheatgrass. The grasses were treated in well-watered or exposed to drought stress by withholding water for 20 days. Visual turf quality of drought-stressed plants had no significant differences with well-watered plants until day 8 of drought and 1727 P10 had the highest turf quality at day 20 of drought. Cluster analysis classified the accessions and Rembrandt into five clusters comprised of drought tolerant (I), intermediate (II, IV and V) and susceptible (III) in response to soil drying. Turf quality, green tissue, relative water content and electrolyte leakage of cluster I (1727 M, 208 M, 4056, 2854 and 1727 P1) were 1.8-, 2.0-, 1.6- and 0.6-fold of cluster III (Rembrandt) under drought stress conditions, respectively. Genetic diversity of cluster I could be used for plant breeding programmes and introduction of the drought-tolerant accessions to turfgrass breeders for drought tolerance varietal development programme.  相似文献   

13.
《Journal of plant nutrition》2013,36(12):2537-2549
Abstract

Selenium (Se), and boron (B), and salinity contamination of agricultural drainage water is potentially hazardous for water reuse strategies in central California. This greenhouse study assessed tolerance and Se, B, and chloride (Cl?) accumulation in different varieties (Emerald City, Samurai, Greenbelt, Marathon) of broccoli (Brassica oleracea L.) irrigated with water of the following different qualities: (1) non‐saline [electrical conductivity (EC) of <1 dS m?1]; (2) Cl?/sulfate salinity of ～5 dS m?1, 250 µg Se L?1, and 5 mg B L?1; and (3) non‐saline and 250 µg Se L?1. One hundred and ten days after transplanting, plants were harvested and dry weight (DW) yields and plant accumulation of Se, B, and Cl? was evaluated in floret, leaf, and stem. Irrespective of treatments floret yields from var. Samurai were the lowest among all varieties, while floret yields from var. Marathon was the only variety to exhibit some sensitivity to treatments. For all varieties, plant Se concentrations were greatest in the floret (up to 51 mg kg?1 DW) irrespective of treatment, and B and Cl? concentrations were greatest in the leaves; 110 mg B kg?1 DW and 5.4% Cl?, respectively. At post harvest, treatment 2 (with salinity, B, and Se) increased soil salinity to almost 6 dS m?1, total Se concentrations to a high of 0.64 mg kg?1 DW soil, and water soluble B concentrations to a high of 2.3 mg B L?1; soluble Se concentrations were insignificant. The results indicate that var. Emerald City, Greenbelt, and Marathon should be considered as recipients of moderately saline effluent enriched with Se and B under field conditions.  相似文献   

14.
Watercress (Nasturtium officinale R. Br.) produces carotenoids and sulfur-containing glucosinolates (GSs) beneficial to human health. Selenium (Se) imparts dietary health properties and substitutes for S in plant biochemical pathways. Experimental objectives were to determine the influence of Se fertilization on 1) biomass, 2) elemental accumulations, 3) carotenoids, and 4) glucosinolates in watercress leaf and shoot tissues. Watercress was greenhouse grown in solution culture with Se treatments of 0, 0.125, 0.25, 0.50, 1.0, 2.0, and 4.0 mg Se L?1, delivered as sodium selenate (Na2SeO4). Fresh and dry biomass were unaffected while shoot tissue Se (P = 0.057) and S (P = 0.003) increased linearly in response to increasing Se treatments. Linear decreases were measured for β-carotene (P = 0.017) and lutein (P = 0.018) in response to increasing Se. Total levels of GS increased, then decreased quadratically (P = 0.003). Results indicate that Se supplementation can increase Se tissue concentrations and GS in watercress; however, carotenoids were negatively affected.  相似文献   

15.
The study evaluates the effect of various potting media, nutrition, and growth regulators on production and nutrient composition of leaf and pseudobulb of Cymbidium hybrid “Baltic Glacier Mint Ice” grown in greenhouses. The results confirmed a positive influence of growth and nutrition on flower yield of Cymbidium, with shredded tree bark+ coconut husk + brick bits giving the best flowering. A nitrogen, phosphorus and potassium (NPK) dose of 200:200:200 mg l?1 with benzyl adenine (BA) and gibberellic acid (GA3) at 50 mg l?1 was found best for growth while an NPK dose of 200:100:100 mg l?1 with BA and GA3 at 50 mg l?1 was suitable flower production of Cymbidium hybrid. Application of an NPK dose of 300:200:300 mg l?1 with BA and GA3 at 500 mg l?1 was found to be best for enhancing flowering frequency. Plants of the Cymbidium hybrid with the best flowering characteristics mostly contained significantly higher concentrations of nitrogen (N), phosphorus (P) and potassium (K) in leaves and pseudobulbs (which acts as reservoir of nutrients).  相似文献   

16.
A greenhouse experiment (5 × 2 × 2 factorial arranged in randomized-complete-design with three replicates) was conducted to assess the combined effects of nickel (Ni) and drought stress on growth and yield parameters of canola (Brassica napus L. var. Talaye) grown on two calcareous soils of loamy and sandy clay textures. Treatments consisted of five Ni levels (0, 0.05, 0.1, 0.5 and 1 mg Ni kg?1 soil) and two levels of water status 100% and 60% field capacity (FC and 0.6FC, respectively). Growth parameters and yield components of plants decreased at drought-stress conditions. Almost all of the studied growth/yield parameters of canola grown on loamy soil were significantly more than those of the sandy clay soil, probably due to the increased capability of loamy soil for supplying the plant water/nutrient requirements. Nickel could positively affect some of the mean growth and yield parameters (e.g., grain yield) over both of the water status conditions. Nevertheless, some of the traits not only increased by Ni fertilization but also decreased compared to that of the control. The positive responses of canola was observed with higher amounts of applied Ni in the sandy clay soil than in loamy soil, e.g., the maximum grain yields of canola grown on loamy and sandy clay soils were obtained with applications of 0.5 and 1 mg Ni kg?1, respectively. Generally, results demonstrated that Ni could not mitigate the negative effects of drought stress on canola growth or yield components.  相似文献   

17.
Drought is an important limiting factor which can cause major loss in barley productivity. A field experiment was conducted to investigate the effects of irrigation regimes on assimilate remobilization and photosynthetic characteristics of five barley cultivars in 2012 and 2013. There were four levels of irrigation including well-watered [soil moisture content in root depth kept at 100% field capacity (FC)], mild drought (75% FC), severe drought (50% FC), and very severe drought (25% FC). Results showed that Karoon and Valfajr cultivars had the maximum net photosynthetic rate (Pn) ranged from 16.3 to 19.3 µmol CO2 m?2 s?1 under very severe drought. Stomatal conductance (gs) was affected by drought so that Karoon and Valfajr had the lowest gs under severe and very severe drought. By improving the drought, remobilization efficiency in Karoon and Valfajr increased from 18.3% in well-watered to 54.1% under severe drought. In both years under severe and very severe drought, maximum 1000-grain weight and grain yield was obtained in Valfajr and Karoon. Overall, in arid areas, applying suitable irrigation regimes such as mild or severe drought can control soil drying, so that suitable cultivars such as Karoon and Valfajr can rehydrate overnight, and yield might not be inhibited severely.  相似文献   

18.
Lygeum spartum, Zygophyllum fabago and Piptatherum miliaceum are typical plant species that grow in mine tailings in semiarid Mediterranean areas. The aim of this work was to investigate metal uptake of these species growing on neutral mine tailings under controlled conditions and their response to fertilizer additions. A neutral mine tailing (pH of soil solution of 7.1–7.2) with high total metal concentrations (9,100 and 5,200 mg kg?1 Zn and Pb, respectively) from Southern Spain was used. Soluble Zn and Pb were low (0.5 and <0.1 mg l?1, respectively) but the major cations and anions reached relatively high levels (e.g. 2,600 and 1,400 mg l?1 Cl and Na). Fertilization caused a significant increase of the plant weight for the three species and decreased metal accumulation with the exception of Cd. Roots accumulated much higher metal concentrations for the three plants than shoots, except Cd in L. spartum. Shoot concentrations for the three plants were 3–14 mg kg?1 Cd, 150–300 mg kg?1 Zn, 4–11 mg kg?1 Cu, and 1–10 mg kg?1 As, and 6–110 mg kg?1 Pb. The results indicate that neutral pH mine tailings present a suitable substrate for establishment of these native plants species and fertilizer favors this establishment. Metal accumulation in plants is relatively low despite high total soil concentrations.  相似文献   

19.
In this study, impact of silicon (Si) application on wheat performance under drought stress is studied. Experimental soil was sandy clay loam with an average pH of 8.01, electrical conductivity (EC) of 2.36 dSm?1, and calcium carbonate (CaCO3) content of 2.16%. Soil was severely deficient in organic matter (<1%). Average extractable phosphorus (P) and potassium (K) concentration was 230 and 5.21 mg kg?1, respectively. Silicon potassium metasilicate (K2SiO3) was applied at the rate of 0 and 12 kg/ha with three canal water irrigation frequencies including two, three, and four under randomized complete block design (RCBD) factorial fashion with three replications. Results indicated that drought stress significantly reduced plant height, spike length, shoot fresh weight, and number of spikelets/spike, eventually enhancing wheat yield. Concentration of K+ in shoot (28.65 mg g?1) and grains (3.51 mg g?1) increased with Si application, which helped to maintain water potential in plant even under reduced moisture level in plants and soil, ultimately producing more yield and biomass under drought stress conditions.  相似文献   

20.
Selenite is a form of selenium (Se) commonly found in Se-excessive soils. To regulate the Se content in plants in high-Se areas, a potted soil experiment was performed on oilseed rape (Brassica napus L.) to evaluate the effects of varied amounts of sulfur (S) on the biomass, accumulation and distribution of Se in B. napus under the conditions of different amounts of Se in the soil. The results showed that the seedlings of B. napus were more sensitive to Se than the mature plants were. The addition of S significantly alleviated the growth inhibition in seedlings and facilitated the growth of mature plants under higher Se (15 mg kg?1) conditions. S treatment significantly decreased soil pH within the range of 0.22–0.60. An appropriate moderate amount (150 mg kg?1) of S exerted the strongest inhibition on Se concentration and accumulation in B. napus at the seedling stage, but a higher amount (300 mg kg?1) of S led to a more significant decrease in the mature plants under higher Se conditions, with the maximum reduction in various parts of B. napus reaching 51.3–60.9% and 42.5–53.4%, respectively. The application of S only affected the uptake of Se, and not the translocation of Se; the accumulation of Se in B. napus follows the sequence of pod ≈ stem > rapeseed > root, and the distribution ratio is approximately 1.00:0.97:0.69:0.49. Overall, the application of S alleviated the inhibitory effect on growth caused by excessive Se by reducing the Se concentration in B. napus and facilitating its growth, suggesting that S treatment is a suitable and highly cost-effective method to regulate the content of Se in B. napus.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号