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1.
Plant production under salinity requires increased capacity for K+ homeostasis. For this purpose, supplementary K2SO4 in the nutrient solution and grafting on a tolerant rootstock were employed in two experiments to test whether grafting, potassium and their interactions can alleviate salinity stress in tomato (Solanum lycopersicum L.). In Exp-ion, plants were cultivated for 122 days to compare different ionic compositions: EC 9 dS m−1 in ECall (by macro-nutrients) and in ECNaCl (by 64.2 mM NaCl), EC 12 dS m−1 in ECK (ECNaCl + 25.8 mM K+). Exp-K+ was established to compare K+ concentrations of 6, 16 and 36 mM at 150 mM NaCl. In both Experiments, ‘ZS-5’, selected as a salt sensitive cultivar, was either self-grafted or grafted onto the cultivar ‘Edkawi’, reported as salt tolerant. Yield and growth, minerals, gas exchange, soluble sugars, and proline were analyzed. Different ionic treatments affected almost all characteristics considered while differences between rootstocks were rarely observed. No pronounced differences were found in shoot growth, yield and gas exchange between ECall and ECNaCl. ECK did not show any salinity alleviative effects but inhibited even growth compared with the other treatments. In Exp-K+, 16 mM K+ increased plant growth, leaf soluble sugars and proline concentrations. 36 mM K+ did not further reduce upper leaf Na+ although leaf K+ concentration increased significantly. The results indicated that the response of tomato plant to NaCl stress was principally attributed to the osmotic component in Exp-ion, excessive K+ showed no mitigating effect on fruit yield and shoot growth. However, 16 mM K+ in the root environment enhanced the salt adaptive capacity of plants stressed at 150 mM NaCl. The use of the tolerant rootstock resulted in no ameliorative effects, owing to its susceptibility to blossom-end rot, failure in enhancing photosynthesis, and ineffectiveness of restraining the long-distance transport of Na+.  相似文献   

2.
Individual and combined effects of salinity and B toxicity on growth, the major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX) activities, ascorbic acid, proline, and H2O2 accumulation, and stomatal resistance (SR), malondialdehyde (MDA), membrane permeability (MP) and the concentrations of sodium (Na), chloride (Cl) and boron (B) of lettuce were investigated. Boron toxicity and salinity reduced growth of lettuce plants. Under B toxicity, B concentration of the plants was increased, but in the presence of NaCl, the concentration of B was significantly reduced. Sodium and Cl concentrations were increased in B + NaCl and NaCl treatments. Membrane damage was more pronounced in NaCl and B + NaCl treatments. Stomatal resistance of the plants was significantly increased by salinity treatments. The accumulation of proline and ascorbic acid was the highest in the B + NaCl treatment. In general, stress conditions significantly increased H2O2 and antioxidant enzyme (SOD, CAT and APX) activities. The present results indicate that stomatal closure is an important response of lettuce against NaCl and B + NaCl stress. Furthermore NaCl and B + NaCl toxicity-induced oxidative stress in lettuce resulting in lipid peroxidation and membrane damage. Increased antioxidant enzyme activities and also accumulation of ascorbic acid and proline are involved in order to overcome B- and NaCl-induced oxidative stress.  相似文献   

3.
Effects of N and S supply on the growth and pungency (estimated as pyruvic acid levels) of Chinese spring onion (Allium fistulosum L. var. giganteum Makino) were investigated in two pot experiments using soilless growing media. In the first experiment the effects of S supply (0.01 and 4.00 mmol L−1 SO42−) on the growth and pungency of Chinese spring onion were investigated among four cultivars with fleshy root type or long pseudostem type. In the second experiment the effects of different S (0.01 and 4.00 mmol L−1 SO42−) and N (1.5, 3.0, 6.0, 12.0 and 24.0 mmol L−1 N) supply levels on the growth and pungency of Chinese spring onion were studied. Fleshy root spring onion had stronger pungency and larger pseudostem diameter than long pseudostem spring onion, and the pungency of fleshy root spring onion was regulated to a greater extent by N and S supply compared with long pseudostem spring onion. Increasing S supply level significantly increased the biomass, N and S uptake and pungency of all cultivars tested. The biomass of Chinese spring onion of fleshy root type (cv Longyao) and long root type (cv Zhangqiu) was more influenced by N supply than it was by cultivar or S supply. Low S supply decreased the pungency of the two cultivars with increasing N supply. No significant differences in N or S uptake or pungency were observed in the two cultivars with different S supply at the N supply level of 1.5 mmol L−1 N, however, cultivar differences in N and S uptake and pungency were investigated at high N supply (12.0 mmol L−1 N) and S supply (4.0 mmol L−1 SO42−). Excessive N supply (24.0 mmol L−1) significantly inhibited plant growth, retarded S assimilation, and decreased pungency. It is therefore essential to apply the optimum recommended rate of N fertilizer in Chinese spring onion production.  相似文献   

4.
Changes caused by NaCl-induced salinity on several growth parameters and ions accumulation have been measured in five olive (Olea europaea L.) cultivars (‘Chemlali’, ‘Chetoui’, ‘Koroneiki’, ‘Arbequina I18’, and ‘Arbosana I43’) growing in a greenhouse in nutrient solution pot experiment. One-year-old plants were transplanted to sand–perlite (1:1) culture, and were irrigated with half-strength Hoagland nutrient solution containing NaCl at various levels (0.5, 50, 100 and 200 mM). Salinity induced significant decrease in growth parameters, but to a different extent in each cultivar. Leaf growth and total leaf area per plant were significantly affected by all salinity treatments in all studied cultivars, being ‘Arbequina I18’ the most sensitive cultivar. Leaf drop phenomenon was observed from 60 days after salt application at high salinity treatments, mainly in Arbequina I18. Contrary to leaf area, leaf thickness increased progressively during the experiment. ‘Chemlali’ developed thicker leaves at the two highest salinity treatments when compared to the other cultivars. Na+ and Cl concentrations were higher in roots than in shoots and leaves in most of the cultivars investigated. The effectiveness of Na+ exclusion mechanism in the roots differed significantly among studied cultivars, working effectively in ‘Chemlali’ (by inhibiting translocation of Na+ to the aerial part) and being much less efficient in ‘Arbequina I18’. Furthermore, leaf abscission can be considered as an additional tolerance mechanism of olive cultivars allowing the elimination of leaves that had accumulated Na+ and Cl ions. Tolerance to salinity stress was as follows: ‘Chemlali’ > ‘Chetoui’ > ‘Arbosana I43’ > ‘Koroneiki’ > ‘Arbequina I18’. This order of salt tolerance was indicated by lower reduction in plant growth parameters (shoot elongation, trunk diameter, total plant dry weight, internodes length, and total leaf area), the increase of leaf thickness, and by the effectiveness of the exclusion mechanism of Na+ and Cl in the root system.  相似文献   

5.
Salt tolerance of five cultivars of Capsicum annuum L. Early Jalapeno, Golden Treasure, NuMex Sweet, NuMex Joe E. Parker, and Santa Fe Grande, two cultivars of C. chinense Jacq. Habanero and Pimienta De Chiera, and one accession of C. annuum, NMCA 10652, were evaluated in a field study. Seedlings were transplanted in late May to field raised beds containing loamy sand soils in a semi-arid environment. Plants were well irrigated throughout the experiment. Three saline solution treatments, prepared by adding NaCl, MgSO4, and CaCl2 to tap water at different amounts to create three salinity levels of 0.82 dS m−1 (control, tap water), 2.5 dS m−1, and 4.1 dS m−1 electrical conductivity (EC), were initiated on 15th June and ended in late August. Among the eight varieties, NMCA 10652 had the highest survival percentage at 100% in the 4.1 dS m−1 treatment, followed by ‘Early Jalapeno’, ‘NuMex Sweet’, ‘Pimienta De Chiera’, ‘Santa Fe Grande’, ‘Golden Treasure’, and ‘NuMex Joe E. Parker’. ‘Habanero’ had the lowest survival at 28%. Compared to control, final shoot dry weight of the plants irrigated with saline solution at 4.1 dS m−1 was reduced by 92% in ‘Habanero’, followed by ‘Golden Treasure’ at 80%. For fruit fresh weight in 4.1 dS m−1 vs. control, ‘Habanero’ had the highest reduction at 86%, followed by ‘Golden Treasure’ at 74%, while NMCA 10652 and ‘Santa Fe Grande’ had the least at 26% and 19%, respectively. NMCA 10652, the most tolerant to salinity, had the lowest leaf Na+ accumulation, while ‘Habanero’, the most sensitive to salinity, had the highest Na+ in the leaves. For leaf Cl, ‘Early Jalapeno’ had the highest, while ‘Habanero’ had the lowest Cl accumulation in the leaves. Generally, sensitive varieties accumulated more Na+ and/or Cl in leaves, except for ‘Early Jalapeno’, which was relatively tolerant to salinity but had high Na+ and Cl accumulation in leaves.  相似文献   

6.
The effect of exogenous silicon (Si) on the growth, boron (B) uptake, stomatal conductance, lipid peroxidation (MDA), membrane permeability, lipoxygenase activity (LOX), proline and H2O2 accumulation, non-enzymatic antioxidant activity (AA) and the activities of major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT and ascorbate peroxidase, APX) of spinach were investigated under greenhouse conditions. Spinach plants were grown with 0 or 30 mg kg−1 B combined with 0 and 150 mg kg−1 Si. The severity of leaf symptoms of B toxicity was lower when the plants were grown with 150 mg kg−1 Si. Silicon supplied to the soil with high B counteracted the deleterious effects of B on root and shoot growth. Application of B significantly increased B concentration in shoot and in root tissues. However, Si decreased B concentration in the shoots but increased it in the roots. Shoot tissues of spinach contained higher B than the roots in all treatments. Applied Si increased the Si concentration of the root and shoot. Stomatal conductance of the plants was decreased by B, but was increased by Si. The concentrations of H2O2 and proline were increased by B toxicity but were decreased by Si applied to plants. Boron toxicity increased the membrane permeability, MDA content and LOX activity of excised leaves of spinach. Applied Si ameliorated the membrane deterioration significantly. Compared with control plants, the activities of AA, SOD, CAT and APX in B-stressed plants without Si applied increased, and application of Si decreased their activities under toxic B conditions. Based on the present work, it can be concluded that Si alleviates B toxicity by preventing oxidative membrane damage and also translocation of B from root to shoots. To our knowledge, this is the first report on the effect of Si in improving B tolerance in spinach.  相似文献   

7.
‘Picual’ olive cuttings were grown in a greenhouse under saline conditions in 2 L plastic pots containing perlite. Plants were irrigated with a nutrient solution plus 75 mM NaCl and 0, 2.5, 10 or 40 mM CaCl2. Vegetative growth, leaf and root Na+ and Ca2+ concentrations were measured. Na+ toxicity symptoms were observed in plants non-treated with Ca2+. Shoot length was higher in Ca2+ treated plants, although shoot growth was reduced at 40 mM CaCl2, probably due to the high total ion concentration reached in the external solution. Ca2+ supply linearly increased leaf and root Ca2+ concentration and decreased leaf Na+ concentration. However, there were no differences in root Na+ concentration. Results indicate Ca2+ may take part in the Na+ exclusion mechanism, mainly preventing Na+ transport to the shoot, that may be an important ability for survival under saline conditions.  相似文献   

8.
Olive (Olea europaea L.) is the major fruit tree in the Mediterranean region, often grown in locations where plants are exposed to increased salinity. To determine the effect of NaCl on shoot and root growth, dry matter allocation, leaf Na+ and K+ concentration, electrolyte (EL) and K+ leakage (KL), seven olive cultivars of different origins were grown in nutrient solution containing 0, 33, 66, 100 or 166 mM NaCl for three months. The general effect of salinity was linear and quadratic decrease of observed plant growth parameters. Different responses of tested cultivars to applied levels of salinity were found for stem dry weight, shoot length and number of leaves. As salinity increased, growth of ‘Manzanillo’ declined sharply, whereas ‘Frantoio’ was the most tolerant to growth reduction in most of the observed growth parameters. Allometric analysis showed that biomass allocation under salinity stress was similar in all cultivars, but the slope between shoot weight and total plant weight decreased as salinity increased. Since the higher allocation in roots was not found, it seems that salinity only slowed the above ground plant canopy growth. Sodium concentration in leaves of all cultivars increased as salinity increased with the highest increment reached when the salinity of nutrient solution was raised from 100 to 166 mM NaCl. Significant differences among genotypes were found in leaf Na+ and K+ concentration and K+:Na+ ratio, but they were not related to the growth rate. Generally, ‘Frantoio’ and ‘Oblica’ accumulated less Na+ and were able to maintain higher K+:Na+ ratios as compared to other genotypes. Electrolyte leakage and KL linearly increased with increasing salinity and the magnitude of the response depended upon the olive cultivar.  相似文献   

9.
Irrigation with saline water is one of the major problems in citrus crop in arid and semi-arid regions. Because rootstock and fertilization play an important role in citrus salt tolerance, we investigated the influence of the nitrogen fertilization and rootstock on salt tolerance of 2-year-old potted Fino 49 lemon trees. For that, trees grafted on Citrus macrophylla (M) or Sour orange (SO) rootstocks were watered for 12 weeks with complete nutrient solution containing either 0 mM NaCl (control, C), 50 mM NaCl (S), 50 mM NaCl with an additional 10 mM potassium nitrate (S + N), or 50 mM NaCl with a 1% KNO3 (S + Nf) foliar spray application. Trees on M were more vigorous than trees on SO and saline treatments reduced leaf growth similarly in trees on both rootstocks. Trees on SO had a lower leaf Cl and Na+ concentration than those on M. Additional soil nitrogen (S + N) decreased leaf Cl concentration and increased leaf K+ concentration in salinized trees on both rootstocks. However, the salinity-induced reduction leaf growth was similar in S + N and S trees. This was due to osmotic effect, beside leaf Cl and Na+ toxicity, played an important role in the growth response of Fino 49 lemon to the salt stress. Additional foliar nitrogen in the S + Nf treatment also reduced leaf Cl concentration relative to the S treatment but trees from S + Nf treatment had the lowest leaf growth. Net assimilation of CO2 (ACO2ACO2), stomatal conductance (gs) and plant transpiration were reduced similarly in all three salt treatments, regardless rootstock. Salinity reduced leaf water and osmotic potential such that leaf turgor was increased. Thus, the salinity-induced ACO2ACO2 reductions were not due to loss of turgor but rather due to high salt ion accumulation in leaves.  相似文献   

10.
Although of considerable agronomic importance, our understanding of B toxicity mechanism in plants is still not completely understood, and remains an open question. Therefore, we investigated the effect of increasing levels of B (0, 10, 20 and 30 mg kg−1) on the growth, boron (B) concentrations, stomatal resistance, lipid peroxidation (MDA), membrane permeability (MP), lypoxygenase activity (LOX), proline (PRO) and H2O2 accumulation, and the activities of major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT and ascorbate peroxidase, APX) of grapevine (Vitis vinifera L. cv. Kalecik Karasi) grafted on 5BB rootstock (V. berlandieri × V. riparia) was investigated. Applied toxic levels of B significantly reduced leaf and root growth and increased the B concentration of the leaf, and stem, bark and root of rootstock. In the all B levels leaf tissues of grapevine accumulated more B than that of the other plant parts. In order to restrict excessive uptake of B, stomatal resistance of the leaves increased especially at high B treatments (20 and 30 mg kg−1). The concentrations of H2O2, MDA and membrane permeability were increased as the result of B toxicity while proline and the activity of lypoxygenase were decreased. Compared with control plants, the activities of SOD and CAT were increased by B treatments while the activity of APX was decreased. To our knowledge, this is the first report that B toxicity elevated the antioxidant enzymes to protect the membrane functions from reactive oxygen species (ROS) injury in grapevine and it was hoped that this study would provide a basis for developing strategies for reducing the risks associated with B toxicity.  相似文献   

11.
This study examines the feasibility of using saline irrigation water for commercial pot cultivation of three ornamentals: Calceolaria hybrida, Calendula officinalis and Petunia hybrida. Two saline treatments were assayed: irrigation with low saline tap water (electrical conductivity = 1.16 dS m−1), and irrigation with a high saline solution of NaCl 100 mM + CaSO4 10 mM + MgSO4 2.5 mM (electrical conductivity = 12.5 dS m−1). When the control plants reached marketable size the watering was stopped and the plant response to drought was studied. Petunia and Calceolaria were tolerant to salinity. Petunia saline-treated plants reduced their growth slightly and increased N and chlorophyll contents in the leaves. Calceolaria experienced a strong reduction in growth and a delay in flowering but no toxicity symptoms or mortality was recorded. These species were moderate NaCl accumulators. Calendula was sensitive to salinity: 16% of the plants died and the surviving ones experienced a heavy reduction of growth, a decrease in chlorophyll and a large accumulation of NaCl in the leaves. Saline pre-conditioned plants of Calceolaria and Petunia were tolerant to drought. In these plants, leaf water content and, specifically, leaf relative water content were sustained longer than in non-pre-conditioned plants throughout the drought period. In Calendula, leaf relative water content decreased at the same rate in pre-conditioned and non-pre-conditioned plants. Consequently, salinization did not confer drought resistance upon this species. Possible factors determining the tolerance to drought in saline pre-conditioned plants are discussed.  相似文献   

12.
Mitogen-activated protein kinases (MAPKs) play important roles in the transduction of extracellular signals to the intracellular targets in all eukaryotes. Here, a cucumber cDNA designated CsNMAPK, encoding a mitogen-activated protein kinase was isolated using RT-PCR, 3′ and 5′ RACE. The full-length cDNA sequence contains 1636 bp and an open reading frame (ORF) of 1113 bp, which encodes 370 amino acid residues. According to the phylogenetic analysis, CsNMAPK belongs to subgroup I MAPK in plants. Northern blot analysis revealed that CsNMAPK expressed differently in response to excess NO3. And the CsNMAPK expression kinetics between a salt-resistant cultivar (Xintaimici) and a salt-sensitive cultivar (Shennongchunwu) was slightly different under 182 mmol L−1 NO3 treatment. The mRNA levels also increased after 24 h treatments with H2O2 and salicylic acid (SA), but decreased with abscisic acid (ABA) and low-temperature. However, there was no significant induction of CsNMAPK gene after 24 h drought and high-temperature treatments. Our results suggested that a MAP kinase cascade may function in excess NO3 and other abiotic stresses in cucumber.  相似文献   

13.
The effects of NaCl stress on plant growth, gas-exchange, activity of superoxide dismutase (SOD), rate of lipid peroxidation, and accumulation of Na+ ion and sugar were investigated in leaves and fruits of pepper plants (Capsicum annuum L.). Especially, the gene expression of l-galactono-1,4-lactone dehydrogenase (GalLDH), which is the last enzyme of ascorbic acid (AsA) biosynthesis, and the relationships between AsA level and Na+ concentration in plant tissue were investigated with increasing salinity. Plants were treated with three treatments: the control (0 mM NaCl) and two salinity levels (50 and 100 mM NaCl) for 21 days under greenhouse conditions. Plant growth was markedly restricted due to the reduction of photosynthetic rate and the increase of Na+ accumulation in leaves with the increasing intensity of NaCl stress. Salinity had more effect on fruit growth comparing to leaf growth, suggesting that fruits could be more sensitive to salinity than leaves. In comparison with the control, salt stress significantly increased lipid peroxidation (as measured as malondialdehyde content) but decreased SOD activity in both fruits and leaves although the effect was larger in fruits; and the rate of the decrease in SOD activity was greater than that of the increase in lipid peroxidation. The AsA concentration transiently increased first 7 days but it slightly decreased from the initial level in the end of treatment day 21. The change in GalLDH gene expression was similar to AsA concentration. The accumulation of Na+, the reduction of AsA level at severe salinity stress were greater in fruits than in leaves; and AsA level had a negative relationship with Na+ concentration in both leaves and fruits. These results suggest that the difference in salt sensitivity between fruits and leaves in pepper plants can be related to the difference in inhibition of AsA synthesis, which in turn is probably due to the toxicity of extreme accumulation of Na+.  相似文献   

14.
The aim of this research was to determine the influence of various forms, diverse doses, and dates of application of nitrogen fertilizers and foliar nutrition on the concentration of sugars, carotenoids and phenolics compound in carrot. Two field experiments (Experiment I in 2003–2005 and Experiment II in 2004–2005) with carrot ‘Kazan F1’ were conducted in Trzciana (50°06′N; 21°85′E) in Poland. Both experiments were arranged in a split-plot design with four replications. Two sub-blocks were identified in both experiments: sub-block (A) without foliar nutrition and sub-block (B) with plant foliar nutrition. In sub-block (B), plants were sprayed three-times with: 2% (w/v) urea, a 1% (v/v) solution of multi-component ‘Supervit R’ fertilizer, and again with 2% (w/v) urea. Combinations with diversified nitrogen fertilization were distinguished within both sub-blocks. The treatments in Experiment I consisted of: (1) Control, (2) 70 kg N ha−1 as Ca(NO3)2, (3) 70 + 70 kg N ha−1 as Ca(NO3)2, (4) 70 kg N ha−1 as (NH4)2SO4 and (5) 70 + 70 kg N ha−1 as (NH4)2SO4, where 70 kg N ha−1 was used preplant and 70 + 70 kg N ha−1 was applied preplant and as a top dressing, respectively. The treatments in Experiment II consisted of: (1) Control, (2) 35 + 35 kg N ha−1 as ENTEC-26, (3) 70 + 70 kg N ha−1 as ENTEC-26, (4) 105 + 105 kg N ha−1 as ENTEC-26, (5) 35 + 35 kg N ha−1 as NH4NO3, (6) 70 + 70 kg N ha−1 as NH4NO3, (7) 105 + 105 kg N ha−1 as NH4NO3, where 35 + 35, 70 + 70, 105 + 105 kg N ha−1 was applied preplant and as top dressing, respectively. Solid nitrogen fertilizer was added to the soil, as produced: Ca(NO3)2—Yara International ASA (Hydro), (NH4)2SO4—Zak?ady Azotowe w Tarnowie, Poland, NH4NO3—Zak?ady Azotowe w Pu?awach, Poland and ENTEC-26–COMPO GmbH & Co., KG, Germany. In Experiment I, the highest sugar concentrations were found in carrot fertilized with (NH4)2SO4 70, while in Experiment II in the control and after fertilization with ENTEC-26 35 + 35 kg N ha−1. In both experiments N-fertilization affected an increase in phenolic compound concentrations in comparison with the control. Experiment I revealed no significant effect of N-fertilization on carotenoid concentrations in carrot, however in Experiment II the highest concentration of these compounds was characteristic for the control plants and carrot fertilized with ENTEC-26 35 + 35. The foliar nutrition applied in Experiment I caused a decline in sugar concentration and an elevated carotenoid concentration, however it had no influence on the phenolic compound concentrations in carrot. Yet the foliar nutrition in Experiment II led to a decrease in phenolic and carotenoid compound concentrations, but it did not affect sugar concentration in carrot.  相似文献   

15.
Two field experiments (Experiment I in 2003–2005 and Experiment II in 2004–2005) with carrot c.v. ‘Kazan F1’ were conducted at Trzciana village (50°06′N, 21°85′E). The experiments were arranged in a split-plot design with four replications. Two sub-blocks were identified in both experiments: I, without foliar nutrition; II, receiving plant foliar nutrition. The plants were sprayed three times alternately with: 2% urea solution, 1% solution of multi-component ‘Supervit R’ fertilizer (produced by Intermag, Poland) and again with 2% urea solution. Combinations with diversified nitrogen fertilization were distinguished within both sub-blocks. Experiment I comprised of: (1) Control, (2) Ca(NO3)2 70, (3) Ca(NO3)2 70 + 70, (4) (NH4)2SO4 70 and (5) (NH4)2SO4 70 + 70. Experiment II included: (1) Control, (2) ENTEC-26 35 + 35, (3) ENTEC-26 70 + 70, (4) ENTEC 26 105 + 105, (5) NH4NO3 35 + 35, (6) NH4NO3 70 + 70, (7) NH4NO3 105 + 105. Where 70 kg N ha−1 was used before sowing, whereas 35 + 35, 70 + 70 and 105 + 105 kg N ha−1 were applied before sowing and as top dressing. Solid nitrogen fertilizer was added to the soil (produced by): Ca(NO3)2, Yara International ASA (Hydro); (NH4)2SO4, Zak?ady Azotowe in Tarnów, Poland; NH4NO3, Zak?ady Azotowe in Pu?awy, Poland; and ENTEC-26, COMPO GmbH & Co. KG, Germany. The research aimed at determining the effect of diversified nitrogen fertilization and foliar nutrition on NO3, NH4+, N-total and dry matter (d.m.) concentrations in carrot, and N uptake by storage roots. In Experiment I, nitrogen fertilization did not affect NO3 concentration, whereas in Experiment II, the applied N treatment increased NO3 concentration in carrot in relation to the control, except for the storage roots of plants fertilized with ENTEC-26 35 + 35. Nitrogen fertilization applied in both experiments caused a significant increase in N-total concentration in carrot and N uptake by storage roots in comparison with the control plants. In both experiments, nitrogen fertilization had a different effect on the concentrations of NH4+ and d.m. in carrot. What is more, foliar nutrition treatments in both experiments had a different effect on the concentrations on NO3, N-total, d.m. in carrot and N uptake by carrot storage roots.  相似文献   

16.
To investigate the feasibility of using salt tolerant rootstock to increase fruit yield and quality of cucumber under NaCl stress, a greenhouse experiment was carried out to determine fruit yield, leaf relative water content, fruit quality, and mineral composition of cucumber plants (Cucumis sativus L. cv. Jinchun No. 2), either self-grafted or grafted onto the commercial salt tolerant rootstock Figleaf Gourd (Cucurbita ficifolia Bouche) and Chaofeng Kangshengwang (Lagenaria siceraria Standl). Plants were grown in a substrate culture (peat:vermiculite:perlite = 1:1:1, v/v) and irrigated with half-strength Hoagland solutions containing 0, 30, or 60 mM NaCl. The results showed that salinity significantly reduced fruit yield of cucumber owing to a decrease both in mean fruit weight and fruit number. Rootstock had no significant effect on leaf relative water content. Plants grafted onto Figleaf Gourd and Chaofeng Kangshengwang had higher fruit number, marketable and total fruit yield than those of self-grafted plants under 0, 30, and 60 mM NaCl, which could be attributed to, at least in part, the higher K+ but lower Na+ and/or Cl contents in the leaves. Salinity improved fruit quality by increasing fruit dry matter, soluble sugar, and titratable acidity contents of all the plants, but had no significant effect on vitamin C content. In comparison to the self-grafted plants, plants grafted onto Figleaf Gourd and Chaofeng Kangshengwang had an overall improved fruit quality under NaCl stress owing to an increase in contents of soluble sugar, titratable acidity, and vitamin C, and a decrease in the percentage of non-marketable fruit and Na+ and/or Cl contents of fruits in comparison to the self-grafted plants, mainly under 60 mM NaCl. Overall, it is suggested that the use of salt tolerant rootstock could provide a useful tool to improve fruit yield and quality of cucumber under NaCl stress.  相似文献   

17.
Twenty-five genotypes of cowpea (Vigna unguiculata L. Walp.) were tested for salt-tolerance at the vegetative growth stage in pot in the greenhouse experiments at salinity levels of 0, 85, and 170 mM NaCl. Plant survival was the main criterion for classifying genotypes. Other criteria included the ion concentration (Na+ and Cl) in root and shoot and biomass accumulation. Four local accessions (‘Paceño’, ‘Tardón’, ‘Sonorense’, and ‘Cuarenteño’), three accessions from California (‘CB46’, ‘CB27’, and ‘CB3’), and one accession from the International Institute of Tropical Agriculture (IITA) (‘IT82D-889’) survived at concentrations of both 85 and 170 mM NaCl and were classified as salt-tolerant, while ‘IT96D-666’, ‘IT89KD-288’, and ‘IT93K-734’ from IITA were classified as salt-sensitive. One local accession (‘Sesenteño’), three accessions from IITA (‘PEPH-V Wes-85’, ‘IT86D-719’, and ‘IT95K-1090-12’), and one accession from California (‘CB5’) were classified as moderately salt-tolerant. Eight accessions from IITA (‘IT96D-733’, ‘IT90K-277-2’, ‘IT91K-93-10’, ‘IT91K-118-20’, ‘IT90K-284-2’, ‘IT95K-1088-4’, ‘IT89KD-391’, and ‘IT94K-437-1’) and one from California (‘CB88’) were classified as moderately salt-sensitive. Biomass was affected by both 85 and 170 mM NaCl in all groups of genotypes, however, salt-tolerant and moderately salt-tolerant genotypes showed higher biomass than genotypes classified as moderately salt-sensitive and salt-sensitive. In all genotypes Cl concentration was higher in shoots than roots and increased as salinity increased. Similarly Na+ concentration increased with increasing salinity. However, in salt-tolerant and moderately salt-tolerant genotypes, Na+ concentration was more in roots than shoots, while in moderately salt-sensitive and salt-sensitive genotypes, Na+ was higher in shoots than roots.  相似文献   

18.
Two plant stress factors, salinity and high levels of boron, often co-occur in natural and agricultural environments. Many investigations have been conducted to document the influence of the combined stresses on crop growth and yield. Only limited information, however, is available concerning the combined effects of the two stresses on mineral ion uptake and partitioning to shoot organs and tissues. Data for this study were obtained from an experiment conducted in greenhouse sand cultures with two water types: (1) a chloride-dominated system, and (2) sulfate-dominated waters characteristic of those present in the San Joaquin Valley of California. Each saline composition treatment was tested at three salinity levels (2, 12, 18 dS m−1) and three B concentrations (0.046, 1.11, 2.22 mM; 0.5, 12, 24 mg L−1). The gradient in B distribution in individual leaves sampled midseason was steep, with less boron accumulating in petioles than in the blades. The highest B concentrations (>100 mmol B kg−1 dry weight) were found in leaf margins of plants grown in the low salinity-high boron treatments. These leaves were cupped upward, an unusual visual symptom characteristic of B toxicity. At final harvest, concentrations of B, Ca, Mg, Na, K, and Cl were highest in the oldest leaves on the broccoli shoots, decreasing acropetally to the heads. Total-P, however, was highest in broccoli heads, decreasing in the older tissues. Leaf-B accumulation was more closely related to salinity rather than to the concentration of Cl in the irrigation waters. Analysis of variance indicated that substrate B had little effect on Cl accumulation in salt-stressed broccoli leaves regardless of water type. No clear cut relationships were evident that would explain the reciprocal effects of B and Cl on crop yields.  相似文献   

19.
We investigated individual and combined effects of B toxicity and salinity in the presence or absence of silicon on the shoot growth, concentrations of sodium (Na), chloride (Cl), boron (B) and silicon (Si), and stomatal resistance (SR), lipid peroxidation (MDA), proline accumulation, H2O2 accumulation and the activities of major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT and ascorbate peroxidase, APX) activity grapevine rootstocks of 41B (V. Vinifera × V. Berlandieri) and 1103P (V. Berlandieri × V. Rupestris). Applied Si counteracted the deleterious effects of salinity and boron toxicity on shoot growth by lowering the accumulation of Na in 1103P, and B and Cl in the both rootstocks. Stomatal resistance, MDA, and the concentrations of H2O2 and proline were higher in the plants grown in conditions of B toxicity, salinity and their combination while applied Si lowered these parameters. Lowering SOD and CAT but increasing APX, Si treatment significantly affected the enzyme activities of both rootstocks. Based on the present work, it can be concluded that Si alleviates the adverse effects of salinity, B toxicity and combined salinity-B toxicity on grapevine rootstocks by preventing both oxidative membrane damage and translocation of Na and B from root to shoots and/or soil to plant, and also lowering the phytotoxic effects of Na and B within plant tissues. When considering the antioxidative response and membrane systems, it was concluded that the rootstock 1103P was responsive to Si under stress conditions. To our knowledge, this is the first report that Si improves the combined salt and B tolerance of grapevine grown under saline, B toxic, and B toxic and saline conditions which describes membrane related parameters and antioxidant responses.  相似文献   

20.
Four different NaCl concentrations in the irrigation water, 0.8, 3, 6 and 9 mol m−3, were applied as experimental treatments to beans (Phaseolus vulgaris L.) grown in completely closed hydroponic systems in a greenhouse. Initially, the Na and Cl concentrations increased rapidly in the root zone, as indicated by the values measured in the drainage water, and this resulted in corresponding increases in the Na/water and Cl/water uptake ratios. However, as these ratios approached equilibrium with the NaCl/water ratios in the irrigation water, the Na and Cl concentrations in the root zone converged to maximal levels, which depended on the treatment. The highest Na and Cl concentrations in the root zone and the corresponding NaCl concentrations in each treatment were used to establish relationships between the external NaCl concentration and the Na/water or Cl/water uptake ratios, which proved to be exponential for Na but linear for Cl. These relationships were then used in a previously established model [Savvas, D., Kotsiras, A., Meletiou, G., Margariti, S., Tsirogiannis, I., 2005a. Modeling the relationship between water uptake by cucumber and NaCl accumulation in a closed hydroponic system. HortScience 40, 802–807] to enable the prediction of the Na and Cl concentrations in the root zone in relation to the cumulative water uptake. The curves predicted by the model followed a convex pattern, with an initially rapid increase in Na and Cl concentrations in the root zone followed by a gradual levelling out as the cumulative water consumption rose. The measured Na and Cl concentrations in the drainage water were more accurately predicted at the higher NaCl concentrations in the irrigation water, although those predicted at 0.8 mol m−3 of NaCl were considered acceptable for use in commercial practice. Bean showed a high efficiency of Na exclusion from the upper leaves, while Cl was readily translocated to the young leaves as the external Cl concentration rose. Plant growth decreased with increasing salinity in a way similar to that reported for beans constantly exposed to comparable salinity levels.  相似文献   

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