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 15 毫秒
1.
Environmentally stressed plants frequently have elevated rates of ethylene evolution and high accumulation of free ammonium by their foliage. The objective of this study was to investigate ethylene evolution and ammonium accumulation by nutrient‐deficient and ammonium‐stressed tomato plants (Lycopersicon esculentum Mill. ‘Heinz 1350’ and neglecta‐1) grown in a greenhouse. In soil culture, ‘Heinz 1350’ was more sensitive to ammonium toxicity and had higher ethylene evolution than neglecta‐1. High ethylene evolution corresponded with appearance of ammonium toxicity symptoms in both lines. In sand culture, ‘Heinz 1350’ and neglecta‐1 grown with K, Ca, or Mg deficiency in NO3 ‐based nutrient solutions had higher ammonium accumulation and higher ethylene evolution than plants grown with complete nutrition. P‐deficient plants had elevated ammonium accumulation but low ethylene evolution. Plants grown on NH4 +‐based nutrition with pH buffering by CaCO3 had lower ethylene evolution and lower ammonium accumulation than plants grown in unbuffered solutions but had higher values than plants grown with NO3 ‐based nutrition. Adequate K nutrition suppressed ethylene evolution and ammonium accumulation for all plants regardless of nitrogen regimes. Ammonium accumulation and ethylene biosynthesis in plants appear to be related processes. They appear to be indicators of stress and may have roles in development of symptoms of nutritional stresses.  相似文献   

2.
Critical concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), and manganese (Mn) with respect to dry matter yield end antagonistic and synergistic relationships among these nutrients were studied in which tomato (Lycopersicon esculentum L.) was grown in recirculating nutrient solution (NFT). Increments of nutrient elements in the nutrient solution increased the proportional rate of the corresponding nutrient elements. Increasing levels of N negatively correlated with plant P and positively correlated with Ca, Fe, and Zn. Iron and Mn contents of the plants were increased and N, K, Ca, and Mg were decreased as a function of P applied. Increases in K in the nutrient solution caused increases in the concentrations of K, N, P, and Zn, and decreases in the concentration of Ca and Fe. Applied Ca increased the concentrations of Ca and N, and decreased the concentrations of P, Mg, Fe, Zn, and Mn. Potassium, Ca, and Fe contents of the plants were decreased and Zn increased, while N, P, and Mn were not affected by the increasing levels of external Mg. Iron suppressed the plant Mg, Zn, and Mn contents. Synergism between Zn and Fe was seen, while P, K, Ca, Mg, and Mn contents were not affected by Zn levels. Potassium, Ca, Mg, and Fe were not responsive to applied Mn, however, N and P contents of the plants were decreased at the highest levels of Mn.  相似文献   

3.
Pot experiments were conducted in the greenhouse to study the effect of nitrogen (N) nutrition on photosynthesis and water relations of barley plants under salinity conditions. Nitrogen decreased the sodium (Na) content and increased the potassium (K) content in shoots. The net photosynthetic rate of leaves increased significantly with added N increasing from 0 to 100 mg N/kg soil. The activity of ribulose 1,5 bisphosphate carboxylase (RuBPCase) in leaves of high‐salt plants was lower, and in leaves of the low‐salt plants higher than that in control plants. The photosynthetic rate was reduced by sodium chloride (NaCl) and was significantly correlated with total soluble protein per unit leaf area. At each N level, stomatal conductance in leaves was reduced considerably by salt. Proline content of leaves increased with increasing N level. It was higher in leaves of salt‐treated plants than in those of control plants. The osmotic potential of leaves decreased with increasing N applied, and the turgor pressure of high N plants remained higher under salt treatment condition.  相似文献   

4.
Two Ca‐efficient and 3 Ca‐inefficient tomato lines selected on the basis of dry matter production, Ca concentrations in tissues, and severity of Ca deficiency symptoms were grown in nutrient solutions containing 6 levels of total Ca ranging from 15 to 365 mg in 70 mg increments. All lines responded to increased Ca supply by increasing in dry weight and by accumulating Ca. The critical Ca concentrations in the shoots were 0.25% and 0.40% on a dry weight basis for the efficient and inefficient lines, respectively. Concentrations of Ca, K, Mg, P, and NO3 were lower in shoots and except for Mg were lower in roots of efficient plants than in the inefficient plants. For all lines as more Ca was available in the media and as Ca increased in the shoots and roots, the concentrations of the nutrients other than Ca declined. The declines in concentrations of K and Mg were not due to dilution by higher dry matter production in the efficient lines relative to the inefficient ones, although the total accumulation of Ca, P, and NO3 did not vary with Ca supplied. Antagonism among cations may account for differences in efficiency among lines of tomato.  相似文献   

5.
The partitioning of biomass between aboveground parts and roots, and between vegetative and reproductive plant parts plays a major role in determining the ability of cotton (Gossypium hirsutum L.) to produce a crop in a given environment. We evaluated the single and combined effects of water and N supply on the partitioning of biomass in cotton plants exposed to two N supply levels, 0 and 12 mM of N, and two water regimes, well irrigated and water‐stressed at an early reproductive stage. The N treatments began when the third true leaf was visible, while water deficit treatments were imposed over the N treatments when the plants were transferred into controlled‐environment chambers at a leaf area near 0.05 m2. Both water deficits and N deficits inhibited total biomass accumulation and its partitioning in cotton. Water deficit alone and N deficit alone inhibited the growth of leaves, petioles, and branches, but did not inhibit growth of the stem and enhanced the accumulation of biomass in squares. When water deficit was superimposed on N deficit, leaf growth was inhibited, although to a lesser extent than when it was the sole stress factor, and the accumulation of biomass in squares was also inhibited. Yet, the dry weight of squares in plants exposed to water and N deficits was greater than that of non‐stressed plants. Water and N deficits, either alone or in combination, did not inhibit the growth of the tap root. Growth of lateral roots was not inhibited either by water deficit alone or in combination with N deficit, but was enhanced when plants were exposed to N deficit alone. Exposure to water deficit alone or in combination with N deficit decreased the shoot:root ratio through the inhibition of shoot growth. Exposure to N deficit alone decreased the shoot:root ratio through the combination of shoot growth inhibition and root growth enhancement.  相似文献   

6.
Three‐week‐old nodulated faba bean plants were subjected to two levels of water stress (0.5 and 0.25 field capacity; soil water content of 20 and 10%) for five weeks. Half of the stressed plants was treated with potassium chloride (KC1) at 10 (K1) and 150 mg (K2)/kg soil at the beginning of water deficit. Nodulation was examined and some nodule activities were assayed. Nodulation, nitrogenase activity, total nitrogen (N), and dry matter yield were significantly decreased by increasing stress but were significantly higher with the two levels of potassium (K) supply. Leghaemoglobin and protein contents of cytosol as well as nodule protease and invertase were severely depressed by drought stress. Soluble carbohydrate contents of nodules, however, was significantly increased. Protein and leghaemoglobin contents and enzyme activities were greater with K fertilization but less soluble carbohydrate was accumulated. The results indicate that K supply, particularly at the 150 mg/kg soil level, increased faba bean resistance to water stress.  相似文献   

7.
Two lines of alfalfa (Medicago sativa L.), a salt‐tolerant AZ‐Germ Salt II and a salt‐sensitive Mesa Sirsa, were grown for three weeks in solution culture containing 0 or 100 mol/m3 sodium chloride (NaCl) in half‐strength Hoagland nutrient solution. Distribution of cations and chloride (Cl) in the leaves of varying ages was determined. The older leaves (age‐dependent) of both lines contained more sodium (Na) in the laminae and petioles than the younger leaves at the salt treatment, whereas the reverse was true for potassium (K) in the laminae. Age‐dependent Cl distribution was only found in the laminae of AZ‐Germ Salt II. Distribution of calcium (Ca) in the lamina and petioles was strongly age‐dependent in both lines, but such a pattern was not found for magnesium (Mg) concentrations. AZ‐Germ Salt II accumulated considerably higher concen‐ trations of Na and Cl in the laminae compared with Mesa Sirsa. The lower Na and Cl concentrations in the laminae of Mesa Sirsa were due to relatively higher accumulation of these ions in the stems. It is concluded that distribution of Na, Cl, and Ca in the leaf laminae is age dependent. Salt tolerance in alfalfa is related to inclusion of Na and Cl in the leaf laminae.  相似文献   

8.
An experiment developed in soilless culture was used to study the effect of several levels of cobalt (Co) (0, 5, 15, and 30 mg.L‐1) on yield and nutrient evolution of the tomato fruits (Lycopersicon esculentum M. cv. Ramy). The incidence of this pollutant in leaf chlorophyll contents was also studied. Increasing concentration of Co in nutrient solution reduced drastically yield in tomato plants. Total, a and b chlorophyll contents were affected by Co level in nutrient solution. A significant increase of nitrogen (N), phosphorus (P), calcium (Ca), and copper (Cu) in the fruit in function of Co treatments were observed. Similar evolution in iron (Fe) and manganese (Mn) fruit content affected by Co presence in higher treatment were obtained. No significant effect of Co presence on potassium (K), magnesium (Mg), sodium (Na), and zinc (Zn) fruit contents were observed. Cobalt absorption was very high, with values of Co in fruit around 250 μg Co g‐1.  相似文献   

9.
Two lines of sunflower (Helianthrus annuus L.), a salt‐tolerant Euroflor and a salt‐sensitive SMH‐24, were grown for three weeks in sand culture containing 0 or 150 mol/m3 NaCl in full strength Hoagland nutrient solution. Distribution of cations in the leaves of varying ages was determined. The older leaves of SMH‐24 contained more sodium (Na) in the laminae than the younger leaves at the salt treatment, whereas laminae of leaves of varying ages of Euroflor maintained Na concentration almost uniform. Distribution of potassium (K), calcium (Ca), and magnesium (Mg) in the laminae was strongly age‐dependent in both lines, i.e., the older leaves contained greater concentrations of these cations than did the younger leaves. The lines did not differ in concentrations of the three cations. The older leaves of SMH‐24 had significantly lower K/Na ratios than those of Euroflor, but the lines did not differ in lamina Ca/Na ratios. It is concluded that distribution of K, Ca, and Mg in the leaf laminae is age‐dependent. Salt‐tolerance in sunflower is related to exclusion of Na in the leaf laminae and to maintenance of almost uniform concentrations of this ion in leaves of all ages.  相似文献   

10.
Abstract

In recent years, ion exchange membranes (IEM) have been used successfully to determine the availability of soil nutrient elements for plants. In general, the procedures proposed are applied to the determination of a single ion, and in only a few of these studies, the selectivity of these IEM was considered. Therefore, this work was conducted (a) to find the most suitable extraction conditions for phosphate (H2PO4 ), nitrate (NO3 ), and sulfate (SO4 2‐) in soils by IEM and their subsequent determination by ion chromatography, (b) to test the effectiveness and selectivity of IEM, (c) to compare the results obtained by IEM with the common procedure for determining the availability of the soil nutrient elements, and (d) to verify whether a relation exits between the concentration of phosphorus (P) extracted by IEM and the plant P requirement. The soil samples used for this study were Humic Cambisols located in four forest plots under natural conditions and four plots fertilized with 100 kg P ha‐1 as triple superphosphate. The efficacy of the IEM was high (85% for SO4 2‐, and 92% for H2PO4 and NO3 ). Statistically significant correlations were obtained between the H2PO4 extracted by IEM and the H2PO4 obtained by the Bray P1 procedure (r2=0.936) and with the H2PO4 extracted using Saunders and Williams (1955) procedure (r2=0.370). The correlation obtained between the amount of NO3 extracted with IEM and that obtained using 2M potassium chloride (KCl) was also highly significant (r2=0.828). The IEM extraction allowed to know in a single extraction process and a single subsequent measurement by ion chromatography the concentrations of soil available H2PO4 , NO3 , and SO4 2‐ ions, which are of great plant nutrition interest. Phosphorus extractable with IEM yielded a close relationship with biomass production and could be used for determining the P requirement of these forest trees.  相似文献   

11.
The experimental system described allows concomitant hourly measurements of CO2, H2O, and NO3 uptake rates by plants grown hydroponically in a greenhouse. Plants are enclosed in an airtight chamber through which air flows at a controlled speed. Carbon dioxide exchange and transpiration rates are determined from respective differences of concentrations of CO2 and water vapor of the air at the system inlet and outlet. This set‐up is based on the “open‐system”; principle with improvements made on existing systems. For instance, propeller anemometers are used to monitor air flow rates in the chamber. From their signal it is possible to continuously adjust air speed to changing environmental conditions and plant activity. The air temperature inside the system therefore never rises above that outside. Water and NO3 uptake rates are calculated at time intervals from changes in the volume and the NO3 concentration of the nutrient solution in contact with the roots. The precise measurement of the volume of solution is achieved using a balance which has a higher precision than any liquid level sensors. Nitrate concentration is determined in the laboratory from aliquots of solution sampled at time intervals. A number of test runs are reported which validate the measurements and confirm undisturbed conditions within the system. Results of typical diurnal changes in CO2, H2O, and NO3 uptake rates by fruiting tomato plants are also presented.  相似文献   

12.
Abstract

This study evaluated the effect of variety and nitrogen (N) fertilization on sucrose, dry‐matter, and cation concentrations in sugarbeet (Beta vulgaris L.) root tissue. A field experiment was conducted on a non‐saline, calcareous Nunn clay loam soil (Aridic argiustoll) using a factorial experimental design with three N‐rates, two varieties, and four replications. Beets were harvested nine times during the growing season. The first and final harvests were on June 25 and October 11, respectively. In addition to the above measurements, purity and extractable sucrose also were measured at the final harvest. Dry‐matter content, sucrose, sums of monovalent and divalent cations, and the monovalent:divalent cation ratios all were influenced significantly by variety, N‐fertilization, and date of harvest. Sucrose concentration was negatively correlated to the sum of monovalent and divalent cations. Root drymatter content was negatively correlated to the monovalent:divalent cation ratio. A relationship of cation concentration to the organic‐ and inorganic‐ anions that influence purity is discussed.  相似文献   

13.
Abstract

Squash (Cucurbita pepo), cucumber (Cucranis sativus), and sweet melon (Cucumis dudain) were grown in sand cultures with N supply concentrations as the variable. For several reasons, total‐N values were found to be less satisfactory than NO ‐N for the purpose of determining the critical nitrogen concentration for maximum growth. Concentrations of total‐N in mature petioles were higher in plants severely deficient in N than in less deficient plants, characteristic of a Piper‐Steenbjerg effect.  相似文献   

14.
The effects on two‐week‐old plants of a salt‐tolerant line (Euroflor) and a salt‐sensitive (SMH‐24) line of sunflower, of varying sodium/calcium (Na/ Ca) ratios in a saline growth medium were assessed after three weeks growth in sand culture under greenhouse conditions. The different Na/Ca ratios of the salt treatment were 36.5, 74.0, and 149, at a constant concentration of 150 mol m‐3 NaCl. Euroflor was superior to SMH‐24 in fresh and dry matters of shoots and roots at varying external Na/Ca ratios. The leaf Na+ concentration in SMH‐24 increased consistently with increase in external Na/Ca ratio, whereas that in Euroflor remained almost unaffected. Although leaf chlorine (Cl) was significantly greater in SMH‐24 than Euroflor, there was no effect of decreasing Ca2+ concentration of the saline growth medium on the leaf Cl concentrations of both lines. The lines did not differ in K+, Ca2+ or Mg2+ concentrations of both shoots and roots. The leaf K/Na and Ca/ Na ratios, K versus Na selectivity were considerably higher in Euroflor than in SMH‐24. The lines also did not differ in leaf water potential and gas exchange and these variables were not affected due to decreasing Ca2+ concentration of the saline growth medium. Stomatal conductance and transpiration remained unchanged in Euroflor, whereas those in SMH‐24 decreased significantly at the highest external Na/Ca ratio. Euroflor had significantly greater stomatal conductance and transpiration than those of SMH‐24 at almost all external Na/Ca ratios, whereas the reverse was true for water use efficiency. It was established that Euroflor was tolerant to low Ca2+ concentrations of the saline growth medium as compared with SMH‐24. This was mainly attributable to accumulation of relatively low Na+ and Cl in the leaves, and maintenance of high leaf K/Na and Ca/Na ratios and K versus Na selectivity in Euroflor.  相似文献   

15.
Abstract

The variability in corn yield responses to applications of Zn fertilizer appears to be associated with several complex soil and climatic factors that affect the availability of endogenous soil Zn to the crop under specific conditions. Among the soil chemical properties that influence availability of endogenous Zn are soil pH, organic matter content, and extractable P. Over a period of several years, soil and plant analysis data were collected from 54 field experiments, field trials, and diagnostic visits to producer's fields. These data were subjected to multiple regression analysis, resulting in an equation: Znleaf = 37.14 + 1.513 Znst ‐4.04 pHst ‐ 1.791 ln(Pst/100) where Znst, pHst, and Pst were 0.1N HC1 extractable soil Zn (kg/ha), 1:1 soil‐water pH, and Bray's 1 extractable soil P (kg/ha), respectively. These factors accounted for 67% of variation in leaf Zn, which was a large portion of the variability in Znleaf considering that climatic conditions, management levels, and varietal differences were uncontrolled in most instances. Using the previously published critical level in the leaf opposite and below the ear as 17 μg Zn/g, these data can be used to set required soil test levels of Zn at different levels of extractable P and soil pH. Inadequate levels of extractable Zn would range from 2.5 (at pH 6.0, P = 70 kg/ha) to, 9.5 kg/ha (at pH 7.5, P = 420 kg/ha).  相似文献   

16.
Abstract

A procedure for the simultaneous extraction of phosphorus, potassium, calcium and magnesium from soils, by an ion‐exchange resin procedure applicable to large‐scale advisory soil testing, is described. The important steps are the disaggregation of soil by shaking in water during 15 minutes with a glass marble, the transference of the elements from the soil to a sodium bicarbonate treated mixture of anion and cation exchange resins during a 16‐hour shaking period, the separation of the resin from the soil by sieving and extraction of the elements from the resin.

The results of resin extractable calcium, magnesium and potassium were comparable to the results of these elements extracted with 1M NH4OAc, to calcium and magnesium extracted with 1M KCl, and to potassium extracted with 0.025M H2SO4.

For phosphorus the resin extractable values were not comparable to the results obtained by the former routine method, based on the extraction with 0.025M H2SO4. The results of resin extractable P presented closer correlation with cotton response to phosphorus application in 28 field experiments (r = 0.85**) as compared with 0.025M H2SO4 extractable P (r = 0.68**), and also with P uptake by flooded rice in a pot experiment with eight lowland soil samples (r = 0.98**), as compared with extraction with 0.0125M H2SO4 in 0.050M HCl, for which the correlation was not significant. The reasons for the superiority of the extraction of P with the described procedure are discussed.  相似文献   

17.
Journal of Soils and Sediments - Compared with deep oligotrophic waters, the distribution and geochemical processes of polycyclic aromatic hydrocarbons (PAHs) in shallow eutrophic waters are more...  相似文献   

18.
Apple (Malus hupehensis Rehd) seedlings were grown in sterilized and non‐sterilized soil with or without phosphorus (P) added and inoculated by VA mycorrhizal (VAM) fungi (Glomus versifome Daniels et Tappe and Glomus macrocarpum Tul et Tul). In sterilized soil, the VAM infection increased the transpiration rate (Tr.) of the leaves, reduced the stomatal resistance (Sr.) and the permanent wilting percentage (PWP) and enhanced the rate of recovery of the plant from the water stress and the plant growth (e.g. leaf number, stem diameter and dry weight). It also increased absorption of most minerals, especially Zn and Cu by the roots and weakened the P‐Cu and P‐Zn interactions. Phosphorus fertilization had some positive effects on the water status, P nutrition and growth, but it reduced the Cu concentration. VAM improved the water status and enhanced drought tolerance of the trees by enhancing absorption and translocation of water by the external hyphae. The efficiency of inoculation in nonsterile soil was not obvious.  相似文献   

19.
The irrigation and nitrogen (N) requirements of potatoes (cv. Delaware) were determined using sprinklers in a line‐source design on a Spearwood sand. Irrigation water was applied at 73 to 244% of the daily pan evaporation (Epan) and N at 0 to 800 kg N ha‐1 (total applied) as NH4NO3 in 10 applications post‐planting. There was a significant yield (total and marketable) response to irrigation, at all levels of applied N, and N at all levels of applied water (P<0.001). The interaction between irrigation and N was also significant (P<0.001). There was no significant yield response to irrigation from 149% Epan (i.e., W3 treatment) to 244% Epan (i.e., W6 treatment). Irrigation at 125 and 150% of Epan was required for 95 and 99% of maximum yield, respectively, as determined from fitted Mitscherlich relationships. Critical levels of N required for 95 (417 kg ha‐1) and 99% (703 kg ha‐1) of maximum yield were also determined from a Mitschlerlich relationship fitted to the average of the W3 to W6 treatments. The percent total N and nitrate‐N in petioles of youngest fully expanded leaves required for 95 and 99% of maximum yield was 1.78 and 2.11, respectively, at the 10 mm tuber stage, and 0.25 and 0.80% at the 10mm plus 14 day stage (from quadratic regressions). There was a significant (P≤0.001) increase in N uptake by tubers with level of applied N from 57 kg ha‐1 at 0 kg applied N ha‐1 to 190 kg ha‐1 at 800 kg applied N ha‐1 (from a Mitscherlich relationship fitted to the average of W3 to W6 treatments). After accounting for N uptake from soil reserves (57 kg N ha‐1), apparent recovery efficiency (RE) of fertilizer N by tubers [RE=(Up‐Uo/Np) where Up=uptake of N by the crop, Uo=uptake in absence of applied N and Np is the level of applied N, expressed as a fraction] declined from 0.28 at 100 kg applied N ha‐1 to 0.17 at 800 kg applied N ha‐1. There was a linear increase in ‘after cooking darkening’ (i.e., greying) of tubers with increasing level of applied N. Conversely, ‘sloughing’ (i.e., disintegration) of tubers decreased (inverse polynomial) with increasing level of applied N. Rate of irrigation had no effect on these cooking qualities. Reducing applied irrigation and N from levels required for 99% of maximum yield to levels required for 95% of maximum yield would not lead to a significant reduction in profit. This would increase apparent recovery efficiency of applied N by plants, maintain tuber quality, and reduce the impact of potato production on the water systems of the Swan coastal plain.  相似文献   

20.
In vitro plantlets or microtubers (in vitro produced tubers) of ‘Spunta’ potato (Solanum tuberosum L.) were planted in a 3 soil: 2 peat moss: 1 sand substrate (by volume) amended with municipal solid waste (MS W) compost at 0, 10, 20, or 30 g 4‐1 L pot. Three months later, plant growth and tuber yield were evaluated and concentrations of shoot and tuber tin (Sn), arsenic (As), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), manganese (Mn), cadmium (Cd), and iron (Fe) were determined. Amending with MSW resulted in significant increases in concentrations of all tested metals in the substrate. Number of proliferated shoots of plants started from rooted plantlets was greatest at 10 g pot‐1 MSW, whereas shoot weight of plants started from microtubers was greatest at 10 and 20 g pot‐1 MSW. Tuber yield of plants started from rooted plantlets or microtubers was greatest at 10 or 30 g pot‐1 MSW, respectively. In all instances, amending with MSW at 30 g pot‐1 resulted in significant increases in concentrations of all tested metals in shoots and tubers. Concentrations of shoot Ni and tuber Zn and Fe for plants started from rooted plantlets and concentrations of shoot Fe and tuber As, Cu and Pb for plants started from microtubers increased consistently with increasing MSW percentage of the substrate. Plants started from rooted plantlets produced shoots with sufficient Zn, Mn, and Ni concentrations regardless of the substrate but with toxic Cu content at 30 g pot‐1 MSW. Plants started from microtubers produced shoots with sufficient Mn and Ni concentrations regardless of the substrate but with low Zn and deficient Cu in unamended substrates. All plants had shoot Fe content higher than the sufficiency range. Although there were significant differences in concentrations of some nutrients among MSW treatments, no symptoms of nutrient toxicity or deficiency were observed. In all instances, tested elements did not accumulate in tubers to levels hazardous to human health. Concentrations of Cd, the most hazardous element, in potato tubers was not high enough to pose a threat to human. Our results indicate that there is a potential use of MSW in satisfying the needs of potato growth with negligible increases in heavy metal concentrations in tubers.  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