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1.
Aragüés  R.  Puy  J.  Isidoro  D. 《Plant and Soil》2004,258(1):69-80
High-density olive orchards are increasing around the world, many of which may be potentially affected by salinity and waterlogging (hypoxia), two important stresses common in irrigated fields in arid and semi-arid climates. However, the response of olive to these stresses under field conditions is not well established. Therefore, our objective was to evaluate the vegetative growth response of young olive trees (Olea europaea L., cv. Arbequina) grown in a spatially variable waterlogged, saline-sodic field. We monitored the growth in trunk diameter of 341, 3-year-old olives between September 1999 and September 2000. Field contour maps were developed delineating soil salinity (ECa), relative ground elevation (RGE) and water table depth (WTD). Soil samples were also collected and analyzed for ECe and SARe in order to characterize the salinity and sodicity profiles and develop the ECa-ECe calibration equation. The infiltration rate (IR) of the crusted and uncrusted soil and the penetration resistance (PR) were also measured. The field was characterized by spatially variable ECe (2–15 dS m–1), SARe (3–40), RGE (–4 to +4 cm) and WTD (0.5–1.9 m, with corresponding ground water EC values between 12 and 6 dS m–1). Steady-state IR of crusted soil was only 7% of the uncrusted soil. Since the field was heavily irrigated by flooding, waterlogging conditions were related to low RGE values. Soil salinity was negatively correlated (R 2 = 0.83, P<0.001) with RGE (ponded water) and WTD (upward flux), due to the evapo-concentration of water and salts at the soil surface. Thus, inverted salinity profiles developed in high salinity areas. Fifty-five percent of the olives were dead 3.5 years after planted, and most of them were located in areas of high ECe (> 10 dS m–1), low RGE (< – 1.5 cm) and low WTD (< 1.2 m). The surviving trees had vegetative salinity tolerance values of ECe threshold = 4 dS m–1 and slope = –12% (i.e., percent decline per unit increase in ECe above the treshold), indicating that the Arbequina olive is moderately tolerant to salinity. The RGE and WTD thresholds for olive's survival were > 0.1 cm and > 1.6 m, respectively. Thus, very small changes in ground elevation had a significant effect on olive's survival or death. The coupled effects of salinity and waterlogging (hypoxia) stresses were most detrimental for olive's growth.  相似文献   

2.
V. Urdanoz  R. Aragüés 《Plant and Soil》2009,320(1-2):219-230
The aim of this work was to evaluate the effects of Fe deficiency on the activity of several metabolic enzymes (PEPC, PK, PFK, G6PDH and G3PDH), along with the function of the antioxidant enzymes (SK, SDH and PAL) in two lines of Medicago ciliaris, TN11.11 and TN8.7. Plants were grown in a greenhouse under controlled conditions. After germination and pre-treatment, plants were transferred for hydroponic culture. Three treatments were used: 30 μM Fe (+Fe), 0 μM Fe (?Fe) and 30 μM Fe + 10 mM NaHCO3 (+Bic.). Our results showed that all the enzymatic activities increased in extracts of Fe-deficient roots when compared to the control. The above increases in the activity were particularly evident for the bicarbonate-treated roots of TN11.11. PEPC activity was increased by 277% in TN11.11 plants with the addition of bicarbonate to the nutrient solution. Our results indicate also that, in the two lines of Medic, the activity of SK, SDH and PAL in leaves and roots were increased under Fe deficiency (either direct or induced by bicarbonate), to a greater extent in TN11.11 plants. Furthermore, a considerable increase in lipid peroxidation of roots and leaves of Fe-deficient plants was observed in TN8.7 when compared to TN11.11 plants. Our data suggest that the TN11.11 line is more effective in overcoming Fe deficiency than TN8.7. The tolerance of TN11.11 to Fe deficiency is related to its ability to modulate the carbohydrate metabolism and to increase secondary metabolism pathways.  相似文献   

3.
Abstract

In vitro culture of rooted and unrooted olive microshoots, established from seed lines of free-pollinated “Frantoio” and “Moraiolo” cultivars, were evaluated for NaCl tolerance. The aim was to use growth and physiological parameters in order to identify salt-adapted genotypes. Leaf tissue elemental distribution of Na, Cl and K was also investigated in unrooted plantlets by cryo-scanning electron microscopy and energy-dispersive X-ray microanalysis. Both in unrooted and rooted plantlets, increased concentrations of NaCl reduced shoot growth, whereas plant survival was not affected. However, no significant interactions between line and NaCl concentration were found. Elemental distribution showed that Moraiolo J and Frantoio Z accumulated more Na and Cl inside leaves, and that these elements followed a tissue-dependent pattern. Rooting capacity was reduced at the higher levels of NaCl. Significant interactions between seed line and salt treatment were found. Seed lines showed different abilities to develop roots at different salt levels. In particular, Frantoio Z showed a significant and different behaviour relative to the other seed lines at 50 mM NaCl with regard to both length and dry weight of roots. The results obtained suggest that rooting parameters are the most useful tools in the evaluation and screening of salt-tolerant olive genotypes through in vitro shoot culture.  相似文献   

4.
Like those of many horticultural crop species, the growth and leaf gas exchange responses of carrot (Daucus carota L.) to salinity are poorly understood. In this study ion accumulation in root tissues (periderm, xylem and phloem tissues) and in leaves of different ages was assessed for carrot plants grown in the field with a low level of salinity (5.8 mM Na(+) and 7.5 mM Cl(-)) and in a glasshouse with salinity ranging from 1-80 mM. At low levels of salinity (1-7.5 mM), in both the field and glasshouse, carrot leaves accumulated high concentrations of Cl(-) (140-200 mM); these appear to be the result of a high affinity for Cl(-) uptake and a low retention of Cl(-) in the root system. However, Cl(-) uptake is under tight control, with an 80-fold increase in external salinity resulting in only a 1.5-fold change in the Cl(-) concentration of the shoot and no increase in the Cl(-) concentration of the root xylem tissue. In contrast to Cl(-), shoot Na(+) concentrations were comparatively low (30-40 mM) but increased by seven-fold when salinity was increased by 80-fold. Growth over the 56-d treatment period in the glasshouse was insensitive to salinity less than 20 mM, but at higher concentrations the yield of carrot tap roots declined by 7 % for each 10 mM increase in salinity. At low levels of salinity the accumulation of high concentrations of Cl(-) (150 mM) in carrot laminae did not appear to limit leaf gas exchange. However, photosynthesis and stomatal conductance were reduced by 38 and 53 %, respectively, for plants grown at a salinity of 80 mM compared with those grown at 1 mM. Salinity-induced reductions in both p(i) and carbon isotope discrimination (delta) were small (2.5 Pa and 1.4 per thousand, respectively, at 80 mM) indicating that the reduction in photosynthesis was only marginally influenced by CO(2) supply. At a salinity of 80 mM the photosynthetic capacity was reduced, with a 30 % reduction in the CO(2)-saturated rate of photosynthesis (A(max)) and a 40 % reduction in both the apparent rate of RuBP-carboxylase-limited CO(2) fixation (V(cmax)) and the electron transport rate limiting RuBP regeneration (J(max)). This study has shown that carrot growth and leaf gas exchange are insensitive to the high leaf Cl(-) concentrations that occur at low levels (1-7 mM) of salinity. However, growth is limited at salinity levels above 20 mM and leaf gas exchange is limited at salinity levels above 8 mM.  相似文献   

5.
6.
Rogers  M.E.  Grieve  C.M.  Shannon  M.C. 《Plant and Soil》1998,202(2):271-280
Sodium and sulphate-dominated salinity is a serious environmental problem occurring in soils and groundwater in many parts of the world. The effect of Na2SO4 and NaCl, at electrical conductivity levels ranging from 2 to 17 dS m-1, on the growth and tissue ion concentrations of 16 lines of lucerne (Medicago sativa L.) was examined in the greenhouse over a 2 month period. Averaged across all lines, plants grown at 17 dS m-1 produced 66% of the dry matter of plants grown at 2 dS m-1. However there were significant differences among lines in relative salt tolerance (as defined by the slope of the reduction in dry matter) versus electrical conductivity. Dry matter production was negatively correlated with shoot concentrations of Na+, Cl- and S2- and generally lines that were more tolerant to salinity had lower concentrations of those ions in the shoots. We conclude that lucerne is moderately tolerant to Na2SO4 -predominated salinity, and that the degree of intraspecific variation that exists within this species will allow more tolerant lines to be selected for establishment in conditions where sulphate salinity is a problem.Collaborator  相似文献   

7.
The comparative responses of young olive trees (Olea europaea L. cv “Chemlali”) to different NaCl salinity levels were investigated over 11 months. One-year-old own rooted plants were grown in 10-L pots containing sand and perlite mixture (1:3 v/v). Trees were subjected to three irrigation treatments: CP (control plants that were irrigated with fresh water); SS1 (salt stressed plants irrigated with water containing 100 mM NaCl) and SS2 plants (salt stressed plants irrigated with water containing 200 mM NaCl). Shoot elongation rate, relative water content, leaf water potential and net carbon dioxide exchange rates decreased significantly with increased NaCl salinity level. Under stressed conditions, the increase of Na+ and Cl ions in both leaves and roots was accompanied with that of proline and soluble sugars. The above results show that the accumulation of proline and sugars under stressed conditions could play a role in salt tolerance. The absence of toxicity symptoms under both stress treatments and the superior photosynthetic activity recorded in SS1-treated plants suggest that cv Chemlali is better able to acclimatize to 100 mM NaCl than at 200 mM NaCl. Our findings indicate that saline water containing 100 mM NaCl, the most available water in arid region in Tunisia, can be recommended for the irrigation of cv Chemlali in the arid south of Tunisia.  相似文献   

8.
Abstract Individual leaves and stems were analysed for Na+, Cl?, K+ and water content in two clones of Agrostis stolonifera differing in salt resistance, during 14 d of treatment with NaCl, 100 and 200 mol m?3, and a further 7 d in a salt-free medium. Great differences in ion and water content were revealed between individual organs, and organ-by-organ analysis also emphasized the differences between the clones better than whole shoot analysis. In both clones, Na+ and Cl? accumulated to the greatest degree in the older leaves, but for corresponding organs, the concentrations were lower in the more tolerant clone. In the sensitive clone, the lowest leaves dehydrated in 200 mol m?3 NaCl and failed to recover, while the plants of the more resistant clone maintained viable water content in all organs. In the resistant clone, K+ concentration decreased less in response to salt treatment than in the more sensitive clone. For a full appreciation of the plants' reactions, it was found necessary to express the analytical data on several bases, namely, per unit dry-weight, unit water, and total ion-content.  相似文献   

9.
10.
The study was conducted to determine whether salt tolerance could be induced in maize at germination stage by soaking of seeds for 8 h in distilled water or in 200 meq·L−1 of NaCl, KCl, CaCl2·2H2O. Both primed and un-primed seeds were subjected for 14 days to 0, 100 or 200 mol·m−3 NaCl under controlled conditions. Although all priming agents were effective in alleviating adverse effects of salt stress on maize at germination stage, CaCl2·2H2O proved to be more effective since the seeds primed with this salt had significantly higher final germination, rate of germination and fresh and dry weights of plumules and radicles than those treated with other salts or distilled water. Concentration of Na+, K+ and Ca2+ increased significantly in all parts of germinating seeds of maize seeds primed with NaCl, KCl, or CaCl2·2H2O, respectively. In addition, seeds primed with CaCl2·2H2O were the highest in Cl accumulation in all parts of the germinating seeds, followed by seeds treated with NaCl and KCl. Most of the Ca2+ was retained in seeds and mesocotyl, because of which, transport of this ion to plumules and radicles was low.  相似文献   

11.
Rogers  M. E.  Grieve  C. M.  Shannon  M. C. 《Plant and Soil》2003,253(1):187-194
The combined effect of NaCl and P on the growth of lucerne was studied in two hydroponic greenhouse experiments. NaCl concentrations were identical in each experiment (0, 50 and 100 mM NaCl) while external P concentrations were low (viz. 0.002, 0.02 and 0.2 mM measured as 0.006, 0.026 and 0.2 mM, respectively) in one experiment and higher (0.5 and 5.0 mM) in the second. Plant biomass was reduced more by the low P levels than by high concentrations of NaCl. A significant NaCl*P effect was found where external P concentrations were low (0.006–0.2 mM) but there was no difference in plant production between the two P concentrations of 0.5 and 5.0 mM. Shoot and root concentrations of Na and Cl increased significantly with increasing NaCl concentration in both experiments and there were some differences in the concentrations of these ions at different external P levels. At low P, NaCl had no significant effect on shoot concentrations of P; however, root P concentrations tended to decrease with increasing NaCl level. Increasing external P from 0.006 to 0.2 mM led to significant increases in P concentrations in both roots and shoots. At higher P, concentrations of P in both the shoots and the roots did not differ with external NaCl or P conditions. Our results illustrate the complex relationship that exists between NaCl and P at low P levels. We conclude that high or non-limiting concentrations of P (0.2 – 5.0 mM) do not affect lucerne's response to NaCl.  相似文献   

12.
Patches of common juniper (Juniperus communis L.) shrubs potentially facilitate the formation of fertile islands in heath tundra ecosystems thereby influencing the long-term resilience of these ecosystems. Although the role of juniper in the formation of such ‘islands of fertility’ has been studied in semiarid landscapes, there has been little attention paid to the importance of juniper in other ecosystems. In this study we contrast the soil fertility and rates of N fixation under juniper shrubs with that in open heath tundra in northern Sweden. Plots were established at several individual sites in alpine heath tundra in Northern Sweden and mineral soils to a depth of 10 cm were characterized for available N and P and total C, N, P, Ca, Mg, K, Fe, Mn, Zn, and Cu. Nitrogen fixation rates were measured by acetylene reduction in feather mosses under juniper canopies and contrasted with N fixation in both feather mosses and surface soils in the open heath. Soils under juniper had concentrations of total P greatly in excess of P in open heath, furthermore, juniper islands had the highest concentrations of bioavailable P. Nitrogen fixation rates in the feather moss Pleurozium schreberi (Bird.) Mitt were approximately 150 μmol acetylene reduced m−2 d−1 under the juniper canopy compared to less than 10 μmol acetylene reduced m−2 d−1 in the open heath. Feather mosses under the juniper canopy also fixed N at a significantly higher rate (on an aerial basis) than that of surface cores from the open heath that included lichen, mosses, and soil crusts. Juniper facilitates the formation of islands of soil fertility that may in turn facilitate the growth of other plants and positively influence the long term recovery of heath tundra ecosystems following disturbance.  相似文献   

13.
Schmull  Michaela  Thomas  Frank M. 《Plant and Soil》2000,225(1-2):227-242
One-year-old seedlings of Quercus robur L., Q. petraea (Matt.) Liebl. and Fagus sylvatica L. were cultivated in lysimeters and subjected to waterlogging for 17 weeks, interrupted by a five-week drainage period during summer. The growth of Q. robur was less affected by waterlogging than that of Q. petraea and Fagus. Waterlogging resulted in the formation of adventitious roots in Q. robur and Q. petraea, but not in Fagus. In contrast to Fagus, Q. robur and, to a lesser extent, Q. petraea were able to generate roots even below the water table. The hydraulic conductance of the excised root systems, the stomatal conductance and, in Fagus, the leaf water potential and the leaf-mass related hydraulic conductance were decreased by waterlogging. The decrease in the hydraulic conductance was largest in Fagus, and smallest in Q. robur. The roots of Fagus responded to anaerobic conditions with an increase in ethanol concentration. The measurements of nitrate reductase activities in roots and leaves provided no indications of a persistent contribution of NO3 metabolism to the alleviation of waterlogging-induced stress. It is concluded that Q. robur and, to a lesser extent, Q. petraea can tolerate waterlogging periods better than Fagus due to a different pattern of root formation, and to a better adjustment of leaf biomass production to the hydraulic conductivity of the root system. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

14.
15.
The phenology of vegetative and reproductive patterns, shoot growth, and the physiological and anatomical plasticity of leaves of ciruela mexicana (Spondias purpurea L) exposed to different ranges of light are described. Flower and fruit production occur during the dry season. Shoot elongation occurs during late spring and summer. Growth rates of S. purpurea are similar to the rates reported for fast growing plants, when growing on rocky slopes in shallow infertile soils. Leaves exposed to the highest photosynthetic photon flux (PPF) had a thicker mesophyll than leaves that developed under the shade. Midday depression of photosynthesis was observed forS. purpurea. The reduction in the rates of net CO2 uptake was related to high temperatures, high PPF, and increased leaf starch content. Plasticity in physiological and anatomical traits as observed in S. purpurea may be advantageous in the low-resource rocky environments where it grows.  相似文献   

16.
Within the genus Olea , the olive ( Olea europaea L.) possesses the largest geographic distribution, and several subspecies have been described. South-west Morocco harbours an endemic olive, O. europaea ssp. maroccana (Greuter & Burdet) P. Vargas et al. , located in the western part of the High Atlas (mainly on the southern slope of the Ida-ou-Tanane massif) and in the western Anti Atlas. The existence and the taxonomic position of this tree have long remained uncertain, but the combination of several morphological traits is unique. Nuclear and cytoplasmic DNA polymorphism also demonstrate that this tree is a well-differentiated and relictual taxon, probably originating from an ancestral unit within tropical Africa. Our findings refute the opinions of several authors who consider ssp. maroccana to be intermediate between the cultivated olive ( O. europaea ssp. europaea ) and the Saharan olive ( O. europaea ssp. laperrinei (Batt. & Trab.) Cif.). According to cpDNA and mtDNA analysis, the Moroccan olive and the Canarian olive ( O. europaea ssp. guanchica P. Vargas et al. ) are related and belong to the same sub-taxon. This biogeographical affinity is strongly supported by other recent phylogenetic studies. The long-term viability of ssp. maroccana is threatened by several factors: (1) limited distribution and reduced numbers of individuals within isolated populations, (2) fragmentation processes related to human and livestock pressures, and (3) putative gene flow between this taxon and the cultivated olive. In order to ensure the long-term survival of this endemic olive, a specific program of conservation should be implemented in the near future.  相似文献   

17.
Toxic levels of extractable soil Al limit production of important crops in many areas of the world. The nature of the limitation in soybeans is not completely understood. Our objectives were to investigate the cause of acid-soil-induced delays in seedling emergence, the effect of acidity on productivity in non-nodulated soybeans and further test the Al tolerance of PI 416,937 compared to a sensitive control, Essex. Growth characteristics of the two genotypes through the flowering stage were measured on a Corozal clay (Aquic Tropudult) in Puerto Rico which had been differentially limed to provide a wide range of soil Al. Early growth was also studied in the laboratory using soil from the field experiment. Highly acidic soil conditions, coupled with high Al levels, reduced growth in both Essex and PI 416,937. The principal factor responsible for delayed emergence in the high Al soil was not delayed radicle initiation, but delayed initiation of hypocotyl elongation. Hypocotyl initiation was highly associated with rate of tap root growth, with the former possibly determined by the latter, because a minimum tap root length of 60 mm was required in both high and low Al soils before hypocotyl initiation commenced. In seedlings, the high acidity reduced root more than shoot growth. By 44 days after planting (DAP), however, soil acidity had reduced shoot growth greatly. Although the soybean plants were not nodulated, foliar N levels and shoot growth were decreased by high Al levels, indicating that interference with N fixation may not be the sole mechanism by which nitrogen accumulation and plant growth is reduced in the field.Joint contribution from the USDA, ARS, Tropical Agriculture Research Station, Mayaguez, PR; USDA, ARS, Soybean and Nitrogen Fixation Research Unit, Raleigh, NC, and the Agricultural Experiment Station-University of Puerto Rico (AES-UPR), Rio Piedras, PR.Joint contribution from the USDA, ARS, Tropical Agriculture Research Station, Mayaguez, PR; USDA, ARS, Soybean and Nitrogen Fixation Research Unit, Raleigh, NC, and the Agricultural Experiment Station-University of Puerto Rico (AES-UPR), Rio Piedras, PR.  相似文献   

18.
The response to increasing NaCl concentration of seedlings of 25 accessions of Ethiopian land races of each of Pennisetum americanum (L.) Leeke (pearl millet) and Eleusine coracana (L.) Gaertn (finger millet), and 15 accessions of Eragrostis tef (Zucc.) Trotter (tef), was examined after two week's growth in NaCl solution culture. Although increasing NaCl concentration significantly reduced seedling root lengths, there was considerable variation within, and between accessions within each species.Analysis based upon a non-linear least square inversion method, using root length data, revealed significant differences in accessions of P. americanum and E. tef on the basis of the estimated salinity threshold, C t , the NaCl concentrations at which root length begins to decrease. C t did not differ significantly between E. coracana accessions. Estimates of C50 and C0, mininum concentrations causing a 50% decrease in root length, and zero root growth respectively, revealed differences between and within accessions for all three species. Overall, finger millet was more tolerant than tef, which was more tolerant than pearl millet. There is clear evidence that differences in tolerance are genetically based from broad sense heritability estimates.  相似文献   

19.
The objective of this research was to determine the optimum nitrogen fertilizer rate for producing sweet sorghum (a promising biofuel crop) juice, sugar, and bagasse on silt loam, sandy loam, and clay soils in Missouri. Seven nitrogen fertilization rates were applied, ranging from 0 to 134 kg N ha?1. Regardless of the soil and year, the juice content of sweet sorghum stalk averaged 68.8% by weight. The juice yield ranged from 15.2 to 71.1 m3 ha?1. Soil and N rate significantly impacted the juice yield (P < 0.0001). The pH and the density of the juice were not affected by the soil or N. The sugar content (Brix) of the juice varied between 10.7% and 18.9%. N fertilization improved the sugar content of the juice. A negative correlation existed between the sugar concentration and the juice yield. In general, the lowest sugar content was found in the clay soil and the impact of the N fertilization on juice sugar content was most pronounced in that soil. The juice sugar yield ranged between 2 and 9.9 Mg ha?1, with significant differences found between years, N rates, and soils. N fertilization always increased the sugar yield in the clay soil, whereas in loam soil, a significant sugar response was recorded when the sweet sorghum was planted after corn. The average juice water content was 84% by weight. The dry bagasse yield fluctuated between 3.2 and 13.8 Mg ha?1 with significant difference found with N rate, soil, and year. When sweet sorghum was grown after soybean or cotton, its N requirement was less than after a corn crop was grown the previous year. In general, a minimum of 67 kg N ha?1 was required to optimize juice, sugar, and bagasse yield in sweet sorghum.  相似文献   

20.
Impact of supplemental UV-B (sUV-B) has been investigated on photosynthetic pigments, antioxidative enzymes, metabolites, and protein profiling of radish plants under realistic field conditions. Exposure of sUV-B leads to oxidative damage in plants. However, plants possess a number of UV-protection mechanisms including a stimulation of antioxidant defense system. It caused alteration in reactive oxygen species metabolism primarily by decreasing catalase activity vis-à-vis enhanced activities of other enzymatic (superoxide dismutase, ascorbate peroxidase, and glutathione reductase) and non-enzymatic (ascorbic acid) antioxidants. Qualitative analysis of samples also showed significant reductions in photosynthetic pigments and protein content. After sUV-B exposure, protein profile showed differences mainly at eight points—126.8, 84.8, 71.9, 61.5, 47.8, 40.6, 38.9, and 17.5 kDa, whereas protein(s) of 38.9 kDa showed increment. Results of the present investigation clearly showed the adverse effect of sUV-B on total biomass at final harvest.  相似文献   

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