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1.
Silicon (Si) and salicylic acid (SA) foliar applications can benefit cotton yield especially if there is stress during cultivation. The objective of this study was to evaluate the foliar application of Si and SA on the photosynthetic variables and cotton yield. The experimental design used was randomized complete block, constituted by Si foliar application in potassium and sodium balanced silicate form (0 and 3.6?g L?1 of Si) and SA (0 and 210?mg L?1). The treatments were applied in three leaf sprays during the reproductive stage that coincided with water stress in tillage. Therefore, the Si foliar application associated with SA favors the physiological variables, increasing the photosynthesis, stomatal conductance and water use efficiency reflecting on the increase of cotton yield.  相似文献   

2.
Wheat (Triticum aestivum L.) residues and nitrogen (N) management are the major problems in the southern part of Iran where irrigated wheat–cotton (Gossypium hirsutum L.)–wheat rotation is a common practice. A 2-year (2009–2011) field experiment was conducted as a split plot design with four replications at a cotton field (Darab), Fars Province, Iran, to determine the influence of different rates of wheat residue (0%, 25%, 50%, and 75%) incorporation and N rates (150, 200, 300, and 400 kg ha?1) on weed suppression, yield, and yield components of cotton. Results showed that a higher residue incorporation and a lower N rate improved weed suppression in both years. For treatments receiving 150 kg N ha?1 and 75% of wheat residues (2250 kg ha?1), weed biomass and density were significantly lower compared to treatments receiving 400 kg N ha?1. The highest cotton lint yield (about 2400–2700 kg ha?1) was obtained by 300 kg N ha?1 in the absence of residue application, in both years. Incorporation of 25% of wheat residue (750 kg ha?1) and application of 300 kg N ha?1 are recommended to guarantee an optimum level of cotton lint yield and weed suppression in a wheat–cotton–wheat rotation in this region.  相似文献   

3.
Two indica rice (Oryza sativa L.) cultivars, viz. ‘Swarna’ and ‘Kalinga III’ were compared for their response to iron (Fe) stress. The cultivars were raised with four Fe levels viz. 0.05, 1, 5, 10 mg L?1 in hydroponic culture. Plant growth, soluble protein, chlorophyll content and phytoferritin of leaves increased significantly with increase in Fe concentration up to 5 mg L?1, but decreased at 10 mg L?1. In contrast, lipid peroxidation, decreased up to 5 mg L?1 then increased at 10 mg L?1. However, at 10 mg L?1 of Fe these parameters were more adversely affected in ‘Swarna’ than ‘Kalinga III’. The later also accumulated relatively more Fe, zinc (Zn), manganese (Mn), and copper (Cu) from the growing medium. Zinc concentrations of the tissue, on the other hand, exhibited the opposite trend. Iron stress may, thus lead to secondary metallic ion stresses and under such situations cultivars like ‘Kalinga III’ will perform better than ‘Swarna’.  相似文献   

4.
The accumulation of total soluble and cell wall-bound phenolics and total soluble proteins in Zea mays plants exposed to drought stress and foliar spray of salicylic acid (SA) at 10?4?mol/L and 10?5?mol/L was investigated. Drought stress was imposed at the four-leaf stage for 10 days (30–35% field capacity). Dehydration of maize leaves was accompanied by the accumulation of both total soluble and cell wall-bound phenolics, reduction in leaf relative water content (LRWC), and shoot and root growth attributes. Foliar spraying of SA further augmented the content of total soluble and cell wall-bound phenolics and total soluble proteins content under drought stress. SA ameliorated the adverse effects of drought stress on LRWC, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, root length and root area. The accumulation of both soluble and cell wall-bound phenolics by foliar spray of SA may be a mechanism related to SA-induced drought stress tolerance in maize. It was concluded that foliar spraying of SA at 10?5?mol/L can be highly economical and effective for modifying the effects of drought stress on maize at the four-leaf stage.  相似文献   

5.
In this study, interactions of nickel sulfate and urea sprays on vegetative growth, yield and leaf mineral contents in strawberry were investigated. Rooted Pajaro strawberry plants were potted in 3 liter pots filled with soil, leaf mold and sand (1:1:1, v/v/v). Established plants were foliar sprayed with nickel sulfate at 0, 150, 300 and 450 mg L?1 and urea 0 and 2 g L?1 concentrations. Results indicated that nickel (Ni; 300 mg L?1) plus urea (2 g L?1) significantly increased the yield and runner numbers. Nickel sulfate at the rate of 300 and 150 mg L?1and urea (2 g L?1) significantly increased the crown numbers. The greatest root fresh and dry weights were obtained from untreated plants. Urea at 2 g L?1 without nickel significantly increased shoot fresh and dry weights. Nickel at 450 mg L?1 without urea significantly increased Ni concentration in leaves. Overall, nickel sulfate at 150 and 300 mg L?1 along with urea at 2 g L?1 were the best treatments.  相似文献   

6.
A two-year field experiment was conducted to elucidate the residual and cumulative boron (B) requirements for cotton and wheat crops. For the first time, cotton was sown in randomized complete blocks those received 0.0, 1.0, 1.5, 2.0, 2.5 and 3.0 kg B ha?1 as borax (Na2B4O7.10H20). Later, each plot was divided into two subplots for successive wheat and cotton crops and half of the pots received B at similar rates. Our results revealed that direct application of B at the rate of 2 and 2.5 kg ha?1 produced optimum cotton yield during 2005. The same rates of B were consistent in residual plots but not in cumulative plots for both of the crops in successive years. It was thus concluded that soil applied B at the rate of 2.0 and 2.5 kg ha?1 had significant residual effects on cotton and wheat yields.  相似文献   

7.
ABSTRACT

Influences of nickel (Ni) concentrations in the nutrient solution on yield, quality, and nitrogen (N) metabolism of cucumber plants (Cucumis sativus cv ‘RS189’ and ‘Vikima’) were evaluated when plants were grown either with urea or nitrate as the sole N source. The cucumber plants were treated with two N sources, urea and nitrate as sodium nitrate (NaNO3) at 200 mg L?1, and three concentrations of Ni as nickel sulfate (NiSO4·6H2O; 0, 0.5, and 1 mg L?1). Treatments were arranged in a randomized block design with six replicates. The highest concentration of Ni in the leaves (1.2 mg kg?1 Dwt) was observed in the urea-fed plants at 1 mg L?1 Ni concentration. Additions of Ni up to 0.5 mg L?1 had no effect on the fruit Ni concentration in the both urea and nitrate-fed plants. Yield significantly (p < 0.05) increased with the Ni supplements from 0 to 0.5 mg L?1 (10 and 15% in ‘RS189’ and ‘Vikima’, respectively), but decreased when 1 mg L?1 Ni applied to the solutions in urea-fed plants. Nitrate-fed plants had a higher percentage of total soluble solids compare to those urea-fed plants. Nitrate concentrations of the fruits in urea-fed plants in both cultivars were reduced by approximately 50% compared to those nitrate-fed plants. The reduction of nitrate concentration in the fruits became more pronounced as the Ni concentration increased in the solution. The rate of photosynthesis (Pn) increased with the increase of the Ni concentration in the solution with urea-fed plants. Both N concentration and nitrate reductase (NR) activity of young leaves were higher in urea-fed plants at 0.5 mg l?1 Ni concentration. Ni supplements enhanced the growth and yield of urea-fed plants by increasing Pn, N concentration and NR activity. It can be concluded that Ni supplements (0.5 mg l?1) improve yield, quality, and NR activity in urea-fed cucumber plants.  相似文献   

8.
A tub experiment was conducted to assess the effect of exogenously applied trehalose (0, 10, and 20 mM) on various attributes of two rice cultivars (Bas-385 and Bas-2000) under salt stress (0, 50, 100, and 150 mM). Salinity decreased growth, gas exchange characteristics, shoot and root potassium (K+) ions, hydrogen peroxide (H2O2), total soluble proteins, activity of catalase (CAT), and yield attributes, while it increased chlorophyll contents, shoot and root sodium (Na+) and calcium (Ca2+), malondialdehyde (MDA), glycinebetain (GB), free proline, and peroxidase (POD) activity. Foliar-applied trehalose improved growth attributes, net photosynthetic rate, GB, total soluble proteins, superoxide dismutase (SOD) and yield. Yield was not obtained at 150 mM salt stress. The rice cultivar Bas-2000 showed better performance with respect to gas exchange attributes and activities of enzymatic antioxidants. Overall, varying levels of foliar-applied trehalose proved to be effective in ameliorating adverse effects of salt stress on rice.  相似文献   

9.
Methodologies that use electromagnetic induction and resistivity in soil profiles to estimate drainage across whole fields and catchments require complex models or measurement systems that are not easily available or difficult to apply at the farm level. The objective of the present study was to define a methodology that could use information easily available to agronomists and commercial cotton consultants to estimate drainage in irrigated Vertisols using a chloride (Cl?) mass balance approach. A secondary objective of this study was to eliminate or minimize the expensive and tedious laboratory analyses for determining Cl? concentration in soils. A model was developed using electromagnetic induction measurements taken with an EM38 instrument in the horizontal mode (EMH) to estimate the chloride concentration in a saturated soil extract in the 0- to 1.2-m depth of irrigated Vertisols. A stepwise linear regression model where the independent variables were soil water storage, exchangeable sodium percentage, and EMH predicted chloride concentration the best. The chloride concentrations thus estimated were similar to measured values only when measured chloride concentrations in the saturated extract were ≤10 meq L?1 (355 mg L?1 = 240 mg kg?1). These values of chloride were then inserted into a chloride mass balance model to estimate deep drainage. In more saline soils, large differences occurred between measured and estimated chloride. Values of drainage based on estimated chloride concentrations in the range of 0–10 meq L?1 were very similar to those based on measured chloride concentrations. There is potential to use an EM38 for quick assessment of deep drainage under irrigated conditions in the field.  相似文献   

10.
局部根系盐胁迫对冬小麦生长和光合特征的影响   总被引：3，自引：1，他引：2  
通过分根装置设置无盐胁迫(0|0)、局部根系150 mmol-L-1NaCl胁迫(0|150)、全部根系75 mmol-L-1NaCl胁迫(75|75)、全部根系150 mmol-L-1NaCl胁迫(150|150)4种处理,研究根系局部盐胁迫对冬小麦生长及光合特征的影响。结果表明:盐胁迫显著抑制了小麦幼苗的生长,并且随着盐胁迫浓度的增加,小麦受抑制程度加重;根系盐胁迫方式对小麦幼苗生长影响显著,局部根系胁迫处理(0|150)小麦幼苗地上部干重比等浓度150 mmol-L-1NaCl全部盐胁迫处理(150|150)增加23.5%,比等浓度75 mmol-L-1NaCl全部盐胁迫处理(75|75)增加17.2%。在局部根系盐胁迫下,非盐胁迫一侧根系(0|150-0)补偿生长,其根长、侧根数、侧根长比盐胁迫一侧根系(0|150-150)分别增加195.2%、206.2%和237.8%,盐胁迫一侧根系吸收的Na+部分向非盐胁迫一侧根系运输,盐胁迫一侧根系(0|150-150)的Na+含量比全部胁迫处理(150|150)减少12.1%。与全部根系盐胁迫相比,局部根系盐胁迫减少了Na+在叶片中的积累,降低了钠/钾值。局部根系盐胁迫叶片净光合速率、气孔导度、胞间CO2浓度和叶绿素荧光参数(Fv/Fm)均高于同浓度完全盐胁迫处理的小麦幼苗,进而增加地上部和根系的生物量。因此,局部根系胁迫显著缓解了全部盐胁迫对小麦地上部和根系生长的抑制作用。  相似文献   

11.
A pot trial with acid yellow-brown soil was conducted to investigate the effects of molybdenum (Mo) and phosphorus (P) fertilizers on cold resistances of winter wheat. Molybdenum was applied at two rates (0 and 0.15 mg Mo kg?1 soil) and P at four rates [0, 100, 200, and 300 mg phosphorus pentoxide (P2O5) kg?1 soil] in experiment 1. Both Mo and P fertilizers were applied at two rates (0 and 0.15 mg Mo kg?1 soil; 0, 150 mg P2O5 kg?1 soil) in experiment 2. Seed yield, soluble sugar, water-soluble protein, ascorbic acid (AsA), malondialdehyde (MDA), and abscisic acid (ABA) concentrations were studied. The results indicated that Mo and P fertilizer increased seed yield, soluble sugar, water-soluble protein, and AsA but decreased the MDA. It implied that appropriate Mo applied with P application had beneficial effects on increasing seed yield and enhancing the cold resistance ability through changing biological substances concentration in winter wheat.  相似文献   

12.
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   

13.
Dry matter production, net photosynthetic rate, leaf nutrient status and trunk anatomical characteristics of Fagus crenata seedlings grown in brown forest soil acidified by adding H2SO4 solution were investigated. The soil acidification leaded to decreased (Ca+Mg+K)/Al molar ratio in the soil solution. Dry mass per plant of the seedlings grown in the soil treated with H+ at 120 mg·L?1 was significantly reduced compared with the control value at 0 mg·L?1. When net photosynthetic rate was reduced in the seedlings grown in the soil treated with H+ at 120 mg·L?1, the carboxylation efficiency and maximum net photosynthetic rate at saturated CO2-concentration were lower than the control values. The addition of H+ to the soil at 120 mg·L?1iinduced a reduction in the concentration of Ca in the leaf. By contrast, the concentration of Al in the leaf was increased with increasing the amount of H+ added to the soil. The annual ring formed in the seedlings grown in the soil treated with H+ at 120 mg·L?1 was significantly narrower than that at 0 (control), 10, 30, 60 or 90 mg·L?1. Based on the results obtained in the present study, we conclude that Fagus crenata is relatively sensitive to a reduction in the (Ca+Mg+K)/Al molar ratio of soil solution compared with Picea abies.  相似文献   

14.
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   

15.
Increased ethylene biosynthesis in cotton tissues have been associated with accelerated fruit abscission and yield losses in waterlogged cotton. In a series of glasshouse and field experiments, we investigated the effect of various application rates (0, 50, 100 and 150 [active ingredient, ai] ha?1) and time (pre- and post-waterlogging) of an anti-ethylene agent, aminoethoxyvinylglycine (AVG) on the growth and yield of cotton. The glasshouse study suggested that AVG (100–150 g [ai] ha?1) applied 24 h prior to waterlogging can increase growth and fruit retention (FR) of waterlogged (WL) and non-waterlogged (NWL) cotton. The positive effects of AVG were further validated in two years of field studies, suggesting that AVG (125 g [ai] ha?1) applied at an early reproductive phase of cotton can significantly increase cotton yield under WL (13%, averaged over two years) and NWL (9%, averaged over two years) environments. Yield increase in AVG-treated cotton was associated with increased number of bolls, boll weight and FR. On the other hand, no further improvement in cotton yield under higher AVG concentration (150 g [ai] ha?1) indicated the saturation of AVG on ethylene inhibition. Thus, appropriate AVG concentration and application timing may help overcome waterlogging-induced yield losses in cotton production systems.  相似文献   

16.
Over application of fertilizer N to cotton is not only a potential threat to environment but also leads to increased costs of cultivation. The study aimed to establish the indicator leaf and its critical greenness for in-season management of fertilizer nitrogen (N) in Bt cotton using chlorophyll (SPAD) meter and leaf color chart (LCC). The response of three varieties and N treatments viz. 0, 30, 60, 90,120, 150 and 180?kg N ha?1 applied in two splits {(50% at thinning and 50% at first flowering) and three splits (50% at thinning, 25% at first flowering and 25% at boll formation)} was studied through split plot design. SPAD values and LCC scores of first, second, third and fourth fully opened leaves from the top of the main stem was recorded at first flowering and boll formation. The physiological efficiency and harvest index was highest for 90?Kg N ha?1 applied in two splits. Beyond 120?kg N ha?1, the N use efficiency parameters were higher for the N treatments applied in three split compared to the respective two split N treatments. The fourth leaf from the top in terms of SPAD values and LCC scores correlated best with N concentration compared to other leaves at all growth stages. The calculated critical SPAD values for the fourth leaf were 45 and 41 at first flowering and boll formation, respectively. Critical score of fourth leaf was 4.1 and 4, respectively at first flowering and boll formation, respectively. It is suggested that color of the fourth leaf from the top of Bt cotton can well indicate N supply from the soil and can help in need based N management.  相似文献   

17.
ABSTRACT

Previous research has shown that supplying adequate sulfur (S) continuously in combination with reduced amounts of nitrogen (N) will produce a quality plant. However, not all commercially available fertilizers use the same source of S, contain the same or optimal concentration of it, or contain any S at all. Additionally, nutrient incompatibility can occur if all the macronutrients are combined in one solution or one dry fertilizer. Thus, the objective of this research was to determine the effect of different methods of application and different types of S fertilizers on chrysanthemum growth. Two experiments were conducted in which three S sources (H2SO4, MgSO4, and K2SO4) were applied in combination with three N concentrations (50, 100, and 150 mg L?1) as fertilizer treatments. Sulfur was applied at 10 mg L?1, either continuously—by slightly acidulating the fertilizer solution with H2SO4—or in one, two, or three single, discrete applications as either K2SO4 or MgSO4. Leaf N concentration was greatest when 100 or 150 mg N L?1 was applied. As expected, S applied continuously by slightly acidulating the fertilizer solution with sulfuric acid resulted in higher leaf S concentration and larger flower diameter than under any of the other treatments. Together, plants fertilized with S continuously at 10 mg S L?1 and N at 100 mg L?1 were the largest, had the largest flower diameter, and contained the greatest leaf N and S concentrations. Sulfur concentration in the mix was highest and N concentration lowest when S was supplied continuously. Thus, if growers need to supply S and acidulate their water, sulfuric acid would be the best choice. If there are concerns about possible S contamination in landfills or in mix recycling, either potassium or magnesium S, applied multiple times as single applications in combination with 100 or 150 mg N L?1, may be a better choice.  相似文献   

18.
The treatment of perchloroethylene (PCE) was investigated by the promotion of Fenton-like reactions using the iron oxyhydroxide goethite (α-FeOOH) as the sole source of the iron catalyst. A silica sand-goethite matrix was contaminated with 5 mg L?1 PCE and the oxidative treatments were conducted with 0.15 mM, 2 mM, 5mM, 10mM, 20mM, and 30mM H2O2. Perchloroethylene was effectively degraded within 96 hr and the most efficient treatment stoichiometry was observed using 0.15 mM H2O2 at pH 3. The degree of heterogeneous catalysis was evaluated by conducting oxidation reactions in parellel systems with an equivalent concentration of soluble iron. The results showed that, within the first 24 hr, up to 94% of the PCE degradation was attributed to heterogeneous catalysis. This modified Fenton's process, when used to treat 5 mg L?1 PCE in natural subsurface materials with 2 mM H2O2 at pH 3, resulted in a residual of 0.20 mg L?1 PCE after 96 hr.  相似文献   

19.
One-year-old loblolly pine seedlings were exposed to 03(≤0.025 or 0.10 μ L L?1, 4 hr d?1, 3 d wk?1) in combination with simulated rain (pH 5.6 or 3.0, 1 hr d?1, 2 d wk?1, 0.75 cm hr?1) for 10 wk. After the 10-wk treatment, the seedlings were submitted to two drought cycles, and water potential, net photosynthesis (Pn), and transpiration (Tr) were measured. Whole-plant fresh weight increment and relative growth rate were significantly increased in seedlings exposed to simulated rain at pH 3.0 compared to pH 5.6. An interaction between 03 and simulated rain occurred in height growth. Shoot height elongation was significantly less in seedlings exposed to 0.10 μL L?1 03 + pH 5.6 than in any other pollutant combination after the 10-wk treatment period. There were no significant effects of 03 on Pn and Tr prior to the drought cycles; however, after the first drought cycle, Pn was significantly higher in seedlings pre-exposed to 0.10 μL L?1 03 compared to the low 03 concentration. The 10-wk treatment with simulated rain at pH 3.0 significantly increased Pn and Tr. The relationship between gas exchange rates and needle water potential during the moisture stress period was affected by preexposure to pollutants. In general, Pn and Tr were more sensitive to decreasing needle water potential in seedlings exposed to pH 3.0 during the first drought cycle and to 0.10 μL L?1 03 during second drought cycle.  相似文献   

20.
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   

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