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1.
Nitrogen metabolism and protein synthesis in plants are severely affected by salt stress, resulting in abnormal plant growth and lower crop yield. The purpose of this investigation was to compare protein synthesis in three green bean ( Phaseolus vulgaris L.) cultivars ('Tender Improved’, ‘Slim Green’, and ‘Kentucky Wonder') under normal (non‐saline) and salt stress with two sources of nitrogen (ammonium‐ 15N and nitrate‐ 15N separately). This comparison was achieved by using 15N under normal (control = 0.3 bars osmotic pressure) and NaCl stress (3.0 bars osmotic pressure), in Hoagland nutrient solution, in a growth chamber. The 5‐day‐old green bean seedlings were grown for 5 additional days in one‐half strength Hoagland solution before and 5 days after the completion of salinization with NaCl. This was followed by a 15‐day 15N uptake period after either ( 15NH 4) 2SO 4 or K 15N0 3 addition to the culture solutions for the ammonium‐ 15N or nitrate‐ 15N treatments, respectively. Plant tissues were analyzed for the crude protein and protein‐N (total and 15N) contents. The crude protein and protein‐N (total and 15N) content of all cultivars significantly decreased under stress conditions for both sources of nitrogen. However, the Tender Improved appeared the least and the Slim Green the most severely affected by salinity among the three cultivars. For all cultivars at each harvest, shoots were more adversely influenced than roots by salt stress when comparing the salinized plants with the controls for each plant part for either source of 15N. The control (non‐salinized) plants contained substantially higher crude protein and protein‐N (total and 15N) when treated with NO 3‐N as compared with NH 4‐N source of 15N. 相似文献
2.
Fertigation with KNO 3 as a means of reducing salinity hazards was tested with peanut (Arachis hypogaea) plants grown on dune sand, resulting in a reduction of plant growth and yield. The objective of this work was to study the interactions between N, K + and NaCl as well as the effects of the NH 4 +/NO 3 ‐ ratio on vegetative and reproductive growth. Wheat ( Triticum aestivum L.) plants were grown in polyethylene pots with fine calcareous dune sand with different proportions of NH 4 + and NO 3 ‐, under saline (60 mM NaCl) and non‐saline conditions. Three replicates were harvested at the beginning of flowering, and one was grown to grain maturity. NaCl reduced shoot dry weight in all the treatments. Increasing the NH 4 + proportion in the total of 6 mM N in the nutrient solution, increased shoot dry weight, did not change nitrogen concentration in the dry mass but increased P percentage, either with or without 60 mM NaCl. The number of tillers produced in each treatment was correlated with dry matter yield. The effect of the NH 4 +/NO 3 ‐ ratio may be explained by alteration of the cation‐anion balance on the nutrient uptake by roots, which lowered pH of the nutrient solution with increasing NH 4 + concentration, by alteration of the cation‐anion balance on the nutrient uptake by roots, which lowered pH of the nutrient solution with increasing NH 4 + concentration. 相似文献
3.
Salinity is a major agricultural problem in arid and semi‐arid regions, resulting in retarded plant growth and reduced crop yield. The purpose of this study was to evaluate the effects of NaCl stress on nitrogen metabolism and protein synthesis in three varieties of green beans, and to select the most salt tolerant and suitable cultivar among the three for cultural practices. To achieve this goal, protein synthesis and protein‐ 15N content of three green bean cultivars ( Phasedus vulgaris L., cv. ‘Tender Improved’, ‘Slim Green’, and ‘Kentucky Wonder') were compared. This comparison was done by using 15N under three different NaCl salinity levels (Control = 0.3, 2.5, and 5.0 bars osmotic pressures), in Hoagland nutrient solution, in a growth chamber. The 7‐day‐old bean seedlings were grown for 7 additional days in complete Hoagland solution before and 7 days after the completion of salinization with NaCl. This was followed by a 15‐day 15N uptake period after 1SNH 4 15NO 3 addition to the culture solutions. Plant tissues were analyzed for crude protein and protein‐N (total and 15N) content. The crude protein and protein‐N (total and 15N) content of plants decreased with increased salinity for all three cultivars, however, the Tender Improved variety was the least severely affected by salinity among the three cultivars. Total crude protein and protein‐N content were substantially higher for shoots than for the roots. Nevertheless, shoots were more severely influenced than roots by salt stress when salinized plants were compared with the controls for each plant part. The adverse effect of salinity on protein synthesis was more severe at the highest (5.0 bars osmotic pressure) level of stress. Based on the results of this study, for growing conditions similar to this experiment, the Tender Improved cultivar appears the most salt tolerant and suitable among these three for cultural practices. 相似文献
4.
Abstract This trial was carried out to establish an appropriate nutrient solution for Aglaonema commutatum and to investigate the nutritional effects generated by modifications in the solution. Six treatments were tested: control (T 0; pH 6.5, E.C. 1.5 dS m ?1, 6 mmol L ?1 NO 3 ?‐N, and 6 mmol L ?1 K +); high nitrogen (N) level (T 1; 9 mmol L ?1 6:3 NO 3 ?–NH 4 +); N form (T 2; 6 mmol L ?1 N‐NH 4 +); high K + level (T 3; 12 mmol L ?1 K +); high electrical conductivity (T 4; E.C. 4 dS m ?1, 25 mmol L ?1 NaCl), and basic pH (T 5; pH 8). At the end of the cultivation, leaf, shoot, and root dry weights and elemental concentrations were determined. Nutrient contents and total plant uptake were calculated from the dry weights and nutrient concentrations. Plant K + uptake increased with application of K + or basic nutrient solution. The uptake and transport of calcium (Ca) were enhanced by the use of NO 3 ?‐N and inhibited by the presence of other cations in the medium (NH 4 +, K +, Na +) and by basic pH. Magnesium (Mg) uptake increased with NO 3 ?‐N application and with pH. Sodium (Na) uptake was the highest in the saline treatment (T 4), followed by the basic pH treatment. Sodium accumulation was detected in the roots (natrophobic plant), where the plant generated a physiological barrier to avoid damage. Dry weight did not differ significantly (p<0.05) among treatments except in the NaCl treatment. These results may help in the formulation of nutrient solutions that take into account the ionic composition of irrigation water and the physiological requirements of plants. 相似文献
5.
The effect of presubmergence and green manuring on various processes involved in [ 15N]‐urea transformations were studied in a growth chamber after [ 15N]‐urea application to floodwater. Presubmergence for 14 days increased urea hydrolysis rates and floodwater pH, resulting in higher NH 3 volatilization as compared to without presubmergence. Presubmergence also increased nitrification and subsequent denitrification but lower N assimilation by floodwater algae caused higher gaseous losses. Addition of green manure maintained higher NH 4+‐N concentration in floodwater mainly because of lower nitrification rates but resulted in highest NH 3 volatilization losses. Although green manure did not affect the KCl extractable NH 4+‐N from applied fertilizer, it maintained higher NH 4+‐N content due to its decomposition and increased mineralization of organic N. After 32 days about 36.9 % (T 1), 23.9 % (T 2), and 36.4 % (T 3) of the applied urea N was incorporated in the pool of soil organic N in treatments. It was evident that the presubmergence has effected the recovery of applied urea N. 相似文献
6.
An investigation was conducted to determine the effect of potassium (K) nutrition on alfalfa (Medicago sativa L.) growth and metabolism of root total nonstructural carbohydrates (TNC) and proteins, and to study whether nitrogen (N) fertilization overcomes N deficiency and low root protein concentrations caused by K deficiency. In Experiment 1, nodulated alfalfa plants were grown in plastic pots containing washed quartz sand and provided minus‐N Hoagland's solution containing 0, 0.6, or 6.0 mM K. Shoot and root K concentrations increased with increasing solution K. Root N concentrations were higher in plants receiving 6.0 mM K than in plants receiving 0.6 or 0 mM K, but shoot N concentrations were similar for all treatments. Plant persistence, shoots per plant, and shoot mass increased as solution K levels increased. Root starch concentration and utilization were positively associated with K nutrition. Total amylase activity was higher, but endoamylase activity was lower in roots of plants receiving 6.0 mM K compared to plants receiving 0.6 or 0 mM K. Root soluble protein concentrations were significantly higher in plants receiving 6.0 mM K than in plants receiving 0 or 0.6 mM K. In Experiment 2, plants were supplied with Hoagland's solution containing 10 mM N as ammonium (NH 4 +) or nitrate (NO 3) with 0,3, or 6.0 mM K. The addition of N increased root N concentrations only in plants receiving 0 mM K. Plant persistence was reduced by NH 4 + application, especially in plants receiving 0 or 3 mM K. Root starch concentrations were markedly reduced in plants receiving NH 4 + at all K levels. The addition of NO 3 ‐ had little effect on alfalfa root carbohydrate and protein metabolism and subsequent shoot growth. Potassium deficiency reduced starch and protein concentrations in roots; factors that were associated with poor persistence and slow shoot regrowth of alfalfa. 相似文献
7.
After a 35 days growth on nutrient solutions with NO ‐ 3 NH 4NO 3 and NH + 4 as nitrogen source (pH 4.2) dry matter yield of the sorghum genotype SC0283 was much less affected by Al (1.5 mg‐ 1) than that of the genotype NB9040. With NO ‐ 3 as the sole nitrogen source only growth of the NB9040 plants was significantly reduced. Since OH ‐ efflux, shoot Al content and concentrations of all major nutrients of both genotypes were almost equal, a higher sensitivity to Al may underlie the lower Al tolerance of the NB9040 genotype. In the presence of NH.‐N Al again lowered d.m. yield of the NB plants. With SCO283 significant Al effects on d.m. yield were observed only with NH 4NO 3. Aluminum drastically increased the amount of protons released per unit of root surface area, especially with the NB9040 line. This shift in proton flux density was partly the result of a decrease of the specific root surface area and partly due to enhanced excess of catlonic nutrients taken up. With NH 4NO 3‐fed plants the latter could almost completely be attributed to a changed N preference brought about by inhibited uptake of NO ‐ 3 and a simultaneous enhanced NH, absorption. Although both proton efflux and NH + 4 preference of the NB plants were severely increased by Al, relative yields of this genotype were not lowered by NH + 4. This can probably be explained by (1) the high NH, sensitivity of this cultivar through which Al effects can be masked and (2) the continuous adjustment of the solution pH through which rhizosphere conditions were prevented. 相似文献
8.
ABSTRACT The addition of carbonates to a nutrient solution to alleviate ammonium (NH 4 +) toxicity in hydroponically-grown cucumber ( Cucumis sativus L.) plants was investigated. Stable isotopes [nitrogen ( 15N) and carbon ( 13C)] were used to assess the uptake of nitrogen [NH 4 + or nitrate (NO 3 ?)] as well as carbon [bicarbonate (HCO 3 ?)/carbonate (CO 3 2?)] by the roots. Ammonium as the sole N source at 5 mM decreased plant fresh weights compared to NO 3 ?. However, at lower concentrations of NH 4 + (25% of 5 mM total N), growth was increased compared to NO 3 ? alone. Inorganic C enrichment [calcium carbonate (CaCO 3)] of the nutrient solution increased the fresh weight of NH 4 + grown plants with up to 150% relative to control plants receiving calcium hydroxide [Ca(OH) 2] for pH regulation. Root 15N enrichment was lower in 15NH 4 + supplied plants compared to 15NO 3 ?, while the 13C enrichment in leaves was increased by NH 4 + nutrition compared to NO 3 ? or NH 4NO 3. The enhanced C capture was associated with high PEPCase activity in the roots. It is concluded that inorganic carbon enrichment of the root medium may alleviate NH 4 + toxicity via increased synthesis of C skeletons and, accordingly, increased capacity for NH 4 + assimilation and N export to the shoots. 相似文献
9.
Cucumber plants were grown hydroponically in three different nutrient solutions to determine the effect of NO 3 ‐/NH 4 + ratio on several parameters. Top and root growth, CO 2 fixation, and ion content (K +, Ca +2, NO 3 ‐) were always lower when urea and ammonium nitrate were the major N source as compared with a Hoagland solution in which nitrate was the major N source. No significant differences were found in total N and protein content among the three nutrient solution treatments. 相似文献
10.
Abstract The efficient use of N for crop production is important because N is normally the most expensive fertilizer input. Past research has suggested that Ca ++ can be used to stimulate NH 4+ absorption by plants. The importance of plant growth stage in relation to this phenomenon has not been examined previously. The objectives of this study were to examine Ca ++ ‐ stimulated NH 4 + absorption and to examine the effect of Ca ++ concentration on N content and growth in plant tops, bulbs and roots at different growth stages. Ammonium absorption experiments were conducted in the greenhouse in 4‐L pots containing 3.5 kg of calcareous Gila sandy loam (Typic Torrifluvents) (CEC <1 cMol kg ?1). Plants (Radish, Raphanus sativas L., and onion, Allium cepa L.) were grown with a uniform nutrient solution (1/2 strength nutrient solution, all N as NO 3) to the desired growth stage at which time the soil was leached with deionized water. Afterwards, the soils were fertilized with 1/2 strength nutrient solutions (5 mol m ?3 NH 4) with Ca ++: NH 4 + molar ratios of 0, 0.25, 0.50, 1.00, and 2.00 for a period of 30 h. As Ca ++ concentration increased, NH 4 + absorption and plant growth increases were greatest with young seedlings. In the intermediate and mature growth stages, Ca ++ stimulated 15NH 4 + absorption was less rapid than in the earlier growth stages but frequently exhibited a different response (i.e., altered metabolite translocation) to the added Ca ++ ‐ concentration. However, at the intermediate and mature growth stages significantly increased N contents and plant growth also were noted in most cases. The Ca ++ ‐ increased N content in leaves and bulbs of the older plants had much less 15N suggesting that the newly absorbed 15NH 4 + was being deposited in the roots replacing older N forms that were then translocated to the bulbs or leaves. Thus, increasing Ca ++ appeared to have anadditional function of increasing the mobility of metabolites (dry matter) from the roots. Since more above‐ground plant products were produced with the same amount of N, plant N use efficiency was increased. 相似文献
11.
Chickpea plants ( Cicer arietinum L cv. ILC 195) were grown for 24 days in water culture under two regimes of nitrogen nutrition (NO 3 or NH 4‐N) with or without Fe. For plants fed with NO 3‐N, Fe stress severely depressed fresh weight accumulation and chlorotic symptoms of Fe‐deficiency developed rapidly. Little difference in growth occurred in the NH 4‐fed plants, whether or not Fe was withheld, with no visual evidence of Fe‐deficiency indicating a beneficial effect of NH 4 in depressing the symptoms of Fe chlorosis. Typical pH changes were measured in the nutrient solution of the control plants in relation to nitrogen supply, increasing with NO 3 and decreasing with NH 4‐nutrition. With both forms of nitrogen, plants acidified the nutrient solution in response to Fe‐stress. Under NH4‐nutrition, acidification was enhanced by withholding Fe. In the NO 3‐fed plants the uptake of all nutrients was reduced by the stress but proportionally NO 3‐ and K + were most affected. Total anion uptake was depressed more than that of cation uptake. For the NH 4‐fed plants withholding Fe resulted in an increased uptake of all ions except NH 4 + which was depressed. Regardless of the form of N‐supply, when Fe was withheld from the nutrient solution the net H + efflux calculated from the (C‐A) uptake values was closely balanced by the OH” added to the nutrient solution to compensate for the pH changes. Evidence of accumulation of organic acids in the Fe‐stressed plants was found, especially in the NO 3‐fed plants, indicating a role for these internally produced anion charges in balancing cation charge in relation to the depression of NO 3 ‐ uptake associated with Fe‐stress. 相似文献
12.
为探讨燕麦对NaCl和KCl胁迫的生理响应差异,采用水培法,研究了不同浓度NaCl和KCl胁迫对幼苗生长,活性氧代谢和渗透调节的影响。结果表明:(1)在75和150mmol/L浓度下,NaCl胁迫对燕麦幼苗的膜脂过氧化伤害和生长抑制大于KCl胁迫。NaCl胁迫下叶片中的超氧化物岐化酶(SOD),过氧化氢酶(CAT)活性及可溶性蛋白、可溶性糖和脯氨酸含量低于KCl胁迫;当浓度增大到225mmol/L时,KCl胁迫叶片中O-2.,H2O2,丙二醛(MDA),可溶性蛋白和可溶性糖含量显著大于NaCl胁迫,而SOD,抗坏血酸过氧化物酶(APX)活性及谷胱甘肽(GSH)含量则相反。(2)225mmol/L KCl和NaCl处理的植株叶片水势分别为-0.867和-1.034 MPa,渗透势分别为-1.409和-1.252 MPa,说明KCl对燕麦的更强伤害不是渗透胁迫所致;经225mmol/L KCl胁迫后,燕麦叶片中Na+含量下降至对照的36.5%,而K+含量上升为对照的1.49倍,而补充20mmol/L NaCl显著提高了225mmol/L KCl胁迫下叶片Na+的含量及SOD,APX活性,降低了K+,H2O2,O-2.和MDA含量,说明离子毒害引起的活性氧积累可能是高浓度KCl胁迫对燕麦幼苗伤害大于NaCl胁迫的重要原因。 相似文献
13.
Under greenhouse conditions, a study was made on the effects of nitrogen (N) source (N)O 3 or NH 4) , mode of application (single vs. split) and nitrification inhibition on the N‐uptake and metabolism, of bahiagrass. Variations in light and temperature in the greenhouse affected the N‐metabolism of bahiagrass plants. Nitrate fed plants had nitrate reductase activity (NRA) pattern different from that of NH4‐fed plants. Amino‐N accumulation patterns were similar for plants under both N‐sources, although amino‐N levels in leaves of NH4‐fed plants were much smaller than that of NO3 plants. Nitrate accumulation in leaves showed inverse trend to that of roots in plants fed both NO3 or NH4. To the sharp peaks in NO3 levels in roots due to increases in light and temperature corresponds a sharp decrease of its levels in leaves. For both both NO3 or NH4 treatments, soluble‐N accumulated most in the rhizomes of bahiagrass plants, whereas protein N accumulated most in leaves, suggesting that rhizomes had a buffering effect on the NO3 fluxes to leaves. This presumably resulted in a lag in the NRA response of the NO3‐fed plants to increases in light and temperature. 相似文献
14.
Abstract Tomato and watermelon plants were grown in nutrient solutions in which nitrogen (N) was supplied as NO 3 ? (6 mM‐N) or NH 4 + (6 mM‐N). The experiments were conducted to evaluate the effect which different N sources exert on iron (Fe) uptake and accumulation, on the enzymatic activities of aconitase (Aco), chelate reductase (FeCH‐R), peroxidase (POD), catalase (CAT), and Fe‐superoxide dismutase (FeSOD), and on biomass production. For both species of plants, fertilization with NH 4 + caused the total Fe concentration to be lower, in the roots and in the leaves in relation to the concentrations recorded in plants fertilized with NO 3 ?. The response of the enzymes related to Fe correlated with their concentration. The plants treated with N?NO 3 ? registered the highest activities in Aco, FeCH‐R, POD, and CAT for both tomato and watermelon. On the other hand, only in the tomato plants was the superoxide dismutase (SOD) activity appreciably influenced primarily by NH 4 +, due possibly to the toxic effect of this N source. Finally, in relation to biomass production, fertilization with NH 4 + drastically reduced growth in the tomato plants, while in watermelon plants, no significant alteration was detected in dry‐matter production, regardless of the N form used. It was concluded that the response of the parameters analyzed to NH 4 + fertilization, in tomato and watermelon, compared to fertilization with NO 3 ? was similar. By contrast, tomato plants, but not watermelon plants, were negatively influenced by NH 4 +. 相似文献
15.
Agricultural systems that receive high amounts of inorganic nitrogen (N) fertilizer in the form of either ammonium (NH 4+), nitrate (NO 3−) or a combination thereof are expected to differ in soil N transformation rates and fates of NH 4+ and NO 3−. Using 15N tracer techniques this study examines how crop plants and soil microbes vary in their ability to take up and compete for fertilizer N on a short time scale (hours to days). Single plants of barley ( Hordeum vulgare L. cv. Morex) were grown on two agricultural soils in microcosms which received either NH 4+, NO 3− or NH 4NO 3. Within each fertilizer treatment traces of 15NH 4+ and 15NO 3− were added separately. During 8 days of fertilization the fate of fertilizer 15N into plants, microbial biomass and inorganic soil N pools as well as changes in gross N transformation rates were investigated. One week after fertilization 45-80% of initially applied 15N was recovered in crop plants compared to only 1-10% in soil microbes, proving that plants were the strongest competitors for fertilizer N. In terms of N uptake soil microbes out-competed plants only during the first 4 h of N application independent of soil and fertilizer N form. Within one day microbial N uptake declined substantially, probably due to carbon limitation. In both soils, plants and soil microbes took up more NO 3− than NH 4+ independent of initially applied N form. Surprisingly, no inhibitory effect of NH 4+ on the uptake and assimilation of nitrate in both, plants and microbes, was observed, probably because fast nitrification rates led to a swift depletion of the ammonium pool. Compared to plant and microbial NH 4+ uptake rates, gross nitrification rates were 3-75-fold higher, indicating that nitrifiers were the strongest competitors for NH 4+ in both soils. The rapid conversion of NH 4+ to NO 3− and preferential use of NO 3− by soil microbes suggest that in agricultural systems with high inorganic N fertilizer inputs the soil microbial community could adapt to high concentrations of NO 3− and shift towards enhanced reliance on NO 3− for their N supply. 相似文献
16.
Displacement of NH 4+ fixed in clay minerals by fertilizer 15NH 4+ is seen as one mechanism of apparent added nitrogen interactions (ANI), which may cause errors in 15N tracer studies. Pot and incubation experiments were carried out for a study of displacement of fixed NH 4+ by 15N‐labeled fertilizer (ammonium sulfate and urea). A typical ANI was observed when 15N‐labeled urea was applied to wheat grown on soils with different N reserves that resulted from their long‐term fertilization history: Plants took up more soil N when receiving fertilizer. Furthermore, an increased uptake of 15N‐labeled fertilizer, induced by increasing unlabeled soil nitrogen supply, was found. This ANI‐like effect was in the same order of magnitude as the observed ANI. All causes of apparent or real ANI can be excluded as explanation for this effect. Plant N uptake‐related processes beyond current concepts of ANI may be responsible. NH 4+ fixation of fertilizer 15NH 4+ in sterilized or non‐sterile, moist soil was immediate and strongly dependent on the rate of fertilizer added. But for the tested range of 20 to 160 mg 15NH 4+‐N kg –1, the NH 4+ fixation rate was low, accounting for only up to 1.3 % of fertilizer N added. For sterilized soil, no re‐mobilization of fixed 15NH 4+ was observed, while in non‐sterile, biologically active soil, 50 % of the initially fixed 15NH 4+ was released up to day 35. Re‐mobilization of 15NH 4+ from the pool of fixed NH 4+ started after complete nitrification of all extractable NH 4+. Our results indicate that in most cases, experimental error from apparent ANI caused by displacement of fixed NH 4+ in clay is unlikely. In addition to the low percentage of only 1.3 % of applied 15N, present in the pool of fixed NH 4+ after 35 days, there were no indications for a real exchange (displacement) of fixed NH 4+ by 15N. 相似文献
17.
Increased above‐ground dry matter and grain yields were found for two hydroponically grown maize hybrids (Pioneer‐3925 and Pioneer‐3949) when plants were supplied with an NH 4 +‐enhanced nutrient solution (31 percent of total N) compared with a control (4 percent of total N as NH 4 +). The major difference in yield developed between silking and 2 weeks post‐silking and silking and 4 weeks post‐silking for the P‐3925 and P‐3949 respectively. The reduced nitrogen content of the stover (leaves plus stalk) was consistently higher on the NH 4 +‐enhanced nutrient solution. The decreased production of the control treatment may have resulted from a reduced photsynthetic capacity. 相似文献
18.
Abstract Tomato plants were grown in sand culture with NH + 4, and NO ? 3, forms of N and three levels of light. Plants supplied with NH + 4, nutrition under high light intensity had symptoms of stunting, leaf roll, wilting, interveinal chlorosis of the older leaves, and one third the dry weight of N0 3‐fed plants. In contrast, growth of plants receiving NH + 4, nutrition under shade appeared normal although dry weight was reduced. NH 4‐N nutrition suppressed K, Ca and Mg accumulation in tissues and increased P contents as compared to NO 3‐N nutrition. 相似文献
19.
The effect of NH 4 + ‐N on root reduction capacity developed during Fe stress was investigated in plants grown in a CaCO 3 buffered nutrient solution. After a 3‐day period of Fe stress, reduction capacity was not increased by the presence of NH 4 + ‐N in the growth medium or in the extracting solution. Since reductant degradation over time was pH dependent, experiments measuring root reductant release into nutrient solution would be confounded by treatments with different solution pH values. In an unbuffered nutrient solution a differential NH 4 + uptake due to the cultivar would affect solution pH and interfere with a reliable interpretation of reductant measurements. 相似文献
20.
以拟南芥野生型、amt1.1和amt1.3为实验材料,采取土培的方法,以正常培养液(4mmol/L NH4+)培养,在20mmol/L NH4+的胁迫下,通过在培养液中添加0%(T1)蔗糖、5%(T2)蔗糖,测定地上部分的鲜重,叶绿素,游离NH4+,可溶性糖,可溶性蛋白,谷氨酰胺合成酶(GS)、谷氨酸脱氢酶(GDH),矿质元素含量等指标,研究外源蔗糖对NH4+胁迫拟南芥碳氮代谢的影响。结果表明,T1处理下,拟南芥生长受到严重的抑制,鲜重,GS,GDH酶活性降低,游离NH4+含量,叶绿素含量,可溶性糖和可溶性蛋白含量增加,植株的N、P、K、Ca的含量增加,Mg、Fe的含量减少。其中col-0在T1处理下受到的抑制比amt1.1和amt1.3更为显著。与T1处理相比较,T2处理增加了拟南芥植株的鲜重,显著提高了可溶性糖和可溶性蛋白含量,提高了GS和GDH的活性;降低了叶绿素和游离NH4+的含量,提高了植株体内的N、P、K、Ca,Mg的含量,降低了植株Fe的含量,其中,外源蔗糖对col-0高NH4+毒害的缓解更为显著。 相似文献
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