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1.
Tumorous crown gall tissue in sunflower (Helianthus annus L.) initiates a mechanism for making Fe available to itself as evidenced by its ability to reduce Fe3+ to Fe2+. The objective of this study was to determine if a limited Fe supply to the plant might affect the growth, nutrition and reduction of Fe3+ to Fe2+ by the tumorous crown gall. Healthy green 14‐day‐old sunflower plants (cv mammoth Russian) were either stem‐inoculated with Agrobacterium tumefaciens to induce tumorous crown gall tissue development or were left uninoculated for comparison. The plants were grown in a modified Hoagland nutrient solution with treatments containing 0.0, 0.15, 0.6 and 2.0 mg Fe L‐1. The 0 mg Fe L‐1 treatment induced maximum Fe chlorosis, and consequently there was a release of hydrogen ions and of a yellow pigment by the roots, but there was no measureable release of ‘reductants’ by the roots. Iron‐deficiency stress (0 mg Fe L‐1) also resulted in reduced tumorous crown gall growth, less reduction of Fe3+ to Fe2+, and lower levels of Fe in the tumorous tissue compared to tumorous tissues adequately supplied with Fe. The tumorous crown gall tissue on the stem reduced much more Fe3+ to Fe2+ than the nontumorous stem tissue regardless of Fe level in the treatment. Tumor tissue contained more Fe, Cu and P than the nontumorous stem tissues which may indicate a modified metabolism in this tissue. An abundant supply of Fe seems to enhance the development and growth of the tumorous crown gall tissue and a deficient supply of Fe retards its growth. 相似文献
2.
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 (15NH4)2SO4 or K15N03 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 NO3‐N as compared with NH4‐N source of 15N. 相似文献
3.
The effects of Zn‐stress on pH of the nutrient medium and the occurrence of Zn deficiency symptoms were examined in 12 cotton and 10 peanut cultivars widely grown in several parts of India. It was found that many of the cotton cultivars were able to reduce the pH, but however unable to recover from Zn deficiency. In contrast, all the peanut cultivars tested did not develop Zn‐chlorosis when subjected to Zn‐stress, although the pH reduction was less significant. The study with these crop cultivars revealed that Zn‐stress tolerance response was not related to pH changes in general. The mechanism by which the peanut cultivars made Zn available and thus averted the onset of Zn‐chlorosis was therefore not adaptive to the changes in pH. This feature appeared to be different from the pattern of correlative pH reduction and recovery from Fe‐chlorosis observed in several Fe‐stress tolerant crop cultivars. 相似文献
4.
Four tomato (Lycopersicon esculentum Mill.) strains (203, 474, 546, and 576) that are equally efficient in potassium (K) absorption, but different in efficiency of K use were studied using a continuously flowing solution culture to determine the importance of K‐transport rate from root to shoot in relation to K‐use efficiency. Strains 203 and 546 are inefficient in K use, ratios of K in shoots to roots were found to be three times higher than those of the two K‐use efficient strains 474 and 576 when grown under low‐K stress (0.1 mM). In addition, both the K concentrations and rates of K flow in xylem exudates of decapitated strains 203 and 546 were significantly higher than those of strains 474 and 576. These results suggest that high rates of K transport from roots to shoots are unrelated to K‐use efficiency in the tomato strains grown under low‐K stress. Further studies of K distributions in leaves and stems found that K concentrations in matured leaves and stems of the two efficient strains 474 and 576 were markedly lower than those of the two inefficient strains 203 and 546, while K in young and expanding leaves of the efficient strains were significantly higher than those of the inefficient strains, indicating that the ability to mobilize K from matured leaves to young and expanding leaves is an important factor that contributes to K‐use efficiency in tomato plants grown under low‐K stress. 相似文献
5.
The objective of this study was to establish whether the iron‐stress responses observed in T203 soybean (Fe‐inefficient) with active nodules are products of the nodules or of the entire root system. A split‐root system was used in which half the roots of each plant were inoculated and actively fixing nitrogen and the other half were not. Soybean cultivar T203 is normally Fe‐inefficient and does not exhibit the Fe‐stress responses, however an iron‐stress response did occur during active N2 fixation in earlier studies. This implies that the active nodules influenced the plant's ability to respond to Fe‐deficiency stress. In this study, the Fe‐stress response (H+ and reductant release) observed in T203 soybean was limited to the inoculated side of the split‐root system. The severe Fe chlorosis which developed in these plants was overcome in a manner similar to Fe‐efficient cultivars undergoing normal Fe‐stress response and the T203 plants completely regreened. Exudation of H+ ions was similar in both the presence and absence of Fe, and was generally limited to inoculated roots. Reductant release was nearly nonexistent from the non‐inoculated roots and was greater for the Fe‐stressed (‐Fe) plants than for non‐stressed (+Fe) plants. Thus, the response observed, which alleviated Fe chlorosis, appeared to be associated with N2 fixation of the active nodules. 相似文献
6.
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
7.
Abstract Although sunflower (Helianthus annus L.) is an Fe efficient plant, tumorous crown gall tissue development and tissue ability to reduce Fe3+ to Fe2+ were both diminished by Fe‐deficiency stress. Crown gall also develops readily on Fe‐efficient and Fe‐inefficient tomato cultivars (Lycopersicon esculentum Mill.). The objective of this study was to determine if the effect of a limited Fe supply on the growth, nutrition and reduction of Fe3+ to Fe2+ by tumorous crown gall would differ between Fe‐efficient T3238FER and Fe‐inefficient T3238fer tomato. Healthy green 25‐day‐old plants were either stem‐inoculated with Agrobacterium tumefaciens to induce tumorous crown gall tissue development or were left uninoculated for comparison. Plants were grown in modified Hoagland nutrient solutions containing 0.0, 0.15, 0.6 and 2.0 mg Fe L?1. Yield of tumorous crown gall tissue was not diminished by low solution Fe in T3238FER, but was in T3238fer. This was attributed to inability of the T3238fer tomato to make Fe available to itself. Tumor tissue from both cultivars contained more Fe, Cu and P than normal stem tissues, which confirms a modified metabolism in these tissues previously observed in sunflower. An abundant supply of Fe enhances the development and growth of the tumorous crown gall tissue, but a deficient supply of Fe retards its growth. 相似文献
8.
Sorghum [Sorghum bicolor (L.) Moench cv RTX430, SC214, SC574, SC599, TAM428, and SC326xSC103] were grown on soils of pH 4.2 or 6.2–6.5. Leaf and nonexserted juvenile panicle tissues were collected at 75 days after planting. Fresh and dry weights were measured and element contents [sulfur (S), phosphorus (P), magnesium (Mg), calcium (Ca), potassium (K), zinc (Zn), iron (Fe), and copper (Cu)] were measured by atomic absorption. Significant cultivar differences in ion concentration (μmol/g dry weight) were found. Juvenile panicles had higher ion concentration (μmol/g dry weight) [S, P, Mg, Ca, K, Zn, and Cu) than leaves. Within leaf tissue, ion concentration (μmol/g dry weight) was correlated with tissue water content (g water/g dry weight). 相似文献
9.
The excretion of phytosiderophores by barley (Hordeum vulgare L.) has recently been documented and a major difference in the Fe‐stress response of gramineous species and dicotyledonous species proposed. However, currently used methods of quantifying and measuring phytosiderophore are tedious or require specialized equipment and a cultivar easily accessible to U.S. scientists is needed. The objectives of this study were (a) to determine if “Steptoe”; and “Europa”; (used as a control cultivar) barleys would release Fe3+ solubilizing compounds in response to Fe‐deficiency stress and (b) to develop a technique to determine the efficiency of solubilization of Fe(OH)3 by the released chelating substances. Two cultivars of barley were place under Fe‐stressed (‐Fe) and nonstressed (+Fe) conditions in modified Hoagland solutions (14 L). The solutions were periodically monitored for H+ and reductant release from the roots and plants were rated daily for chlorosis development. Periodic (6 or 7 harvests) evaluation of the release of Fe3+ solubilizing substances was performed as herein described. Neither H+ nor reductant extrusion occurred with either cultivar during Fe stress. However, Fe3+ solubilizing substances were released by both cultivars at relatively high levels under Fe‐stress conditions compared to the nonstressed plants. A convenient technique was developed to measure the release of Fe solubilizing substances released by barley roots. 相似文献
10.
The Fe‐inefficient T203 and the Fe‐efficient A7 and Pioneer 1082 (P1082) soybeans (Glycine max (L.) Merr.) were grown hydroponically with no (0 mg Fe L‐1 ; ‐Fe) and a minute level (0.025 mg Fe L‐1 ; +Fe) of Fe to (a) compare their responses to Fe‐deficiency stress and (b) relate Fe‐efficiency in soybeans to their ability to initiate the Fe‐stress‐response mechanism at low levels of Fe. With no Fe in solution, P1082 released similar levels of H+ ions, but released less reductant from their roots and there was less reduction of Fe3+ to Fe2+ by their roots than by A7 roots. These responses were also one day later and occurred after a more severe chlorosis and a lower leaf Fe had developed in P1082 than in A7. With 0.025 mg L‐1 of solution Fe, it was not necessary for the Fe‐stress response mechanism to be fully activated to make Fe available in A7 soybean, whereas a strongly enhanced Fe stress response was observed in P1082. Increased Fe uptake and regreening of leaves immediately succeeded initiation of the Fe stress response in both cultivars and at both levels of Fe. Thus, P1082 was slightly less efficient than A7 soybean, but would be classed more efficient than the previously studied soybean cultivars A2, Hawkeye, Bragg, Pride, Anoka, and T203. These results support the hypothesis that the most efficient soybeans are those which can initiate the Fe‐stress response mechanism with little or no Fe in the growth medium. The near simultaneous occurrence of the factors in the Fe‐stress response mechanism (H ion and reductant release, reduction of Fe to Fe by roots), and the immediate increase in leaf Fe and chorophyll contents following that response suggest that all these factors act in concert, not independently, to aid in the absorption and transport of Fe to plant tops. 相似文献
11.
Plant growth, leaf chlorosis, root reductive capacity, rhizosphere pH, and phytosiderophore release capacity were used as indices to evaluate the responses of maize (Zea mays L. cv ‘clipper'), millet (Pennisetum glaucum L. cv. ‘Dwarf Gero'), sorghum (Sorghum bicolor L. cv. YG 5760), barnyard grass (Echinochloa crus galli L. cv: unknown), wheat (Triticum aestivum L. cv. ‘tonic'), and white lupin (Lupinus albus L. cv ‘lucky') to iron‐deficiency stress. Generally, root and shoot dry matter increased with iron treatment and leaves became less chlorotic. Neither the order nor the magnitude of the root reductive capacities of the monocots studied was affected by iron deprivation, but these reductive capacities and the changes in rhizosphere pH differed markedly. Significant iron stress‐induced phytosiderophore release was observed only in wheat and sorghum in which accompanying increases in rhizosphere pH were also evident. Such phytosiderophore release matched the severity of leaf chlorosis and iron uptake and depended on the form in which the element was supplied. These results, from experiments conducted in non‐axenic hydroponic cultures, indicate that in iron‐ deficiency stress mechanisms ‐ similar to those found in dicots ‐could account for iron uptake in some graminaceous monocots, and that strategy II‐type response proposed for all in this category of plants would be an over simplification. 相似文献
12.
Differential response of groundnut genotypes to iron‐deficiency stress was studied in soils containing high calcium carbonate. Genotypes differed significantly for some traits that appeared to be important in determining adaptation to low iron. The genotypes TCGS 273, TCGS 2, TCGS 37, and Kadiri 3 had higher total chlorophyll, total dry matter, and active iron (Fe2+) contents under iron‐deficiency stress conditions. Total chlorophyll followed by active iron were found to be sensitive parameters to Fe deficiency. Based on the visual deficiency symptoms (chlorosis score), the genotypes were classified into three groups. Efficient (no genotype was found efficient), moderately efficient (TCGS 273, TCGS 2, TCGS 3, and Kadiri 3), and inefficient (TCGS 1, TCGS 7, TCGS 11, TCGS 26, TCGS 28, TCGS 29, TCGS 30, TCGS 1518, TPT 1, TPT 2, ICGS 11, ICGS 44, Girnar, JL 24, ICGS(E) 21, and TMV 2). 相似文献
13.
Seshadri Kannan 《Journal of plant nutrition》2013,36(12):1191-1197
The phenomenon of Fe‐stress response mechanism was examined using papaya as a test fruit plant species. This plant behaved like the many Fe‐efficient crop cultivars, reduced the pH of the minus Fe nutrient medium, followed by recovery from chlorosis. The response mechanism was observed in both the 2 cultivars, CO‐1 and CO‐3. Evidence obtained with this plant supports the widespread occurrence of the mechanism in diverse crop species ‐ grain, vegetable and fruit crop plants too. 相似文献
14.
Seshadri Kannan 《Journal of plant nutrition》2013,36(12):1025-1031
Fe‐deficiency chlorosis was induced in 4 lentil (Lens esculenta Moench) and 7 sesame (Sesamum indicum L.) cultivars by growing them in full nutrient solution for 20 days and then in the nutrient medium without Fe. In lentil cv. VL‐1, a mild chlorosis appeared but turned green after 14 days of stress. However, this recovery was not paralleled by a decrease in pH of the medium. In sesame, there were differences in the degree of tolerance. The cv. T‐13 did not develop any chlorosis, and the pH was found to steadily decrease to 4.5. The cv. SP‐1181 lowered the pH to only 5.6, and did not recover from the chlorosis. A second pattern was noted in VS‐2, TS‐25, TMV‐3 and TMV‐4; these cultivars reduced the pH to between 4.1 and 4.5; these showed a mild chlorosis which disappeared later.
The results show that the pH reduction is not a requisite for chlorosis recovery, at least in some crop cultivars. There are obviously some other mechanism which makes Fe available to the chlorotic leaves. It is suggested that a retranslocatlon of Fe from the older leaves may take place under the stress condition through some physiological process. 相似文献
15.
J. Moreno‐Caselles A. Pérez‐Espinosa M. D. Pérez‐Murcia R. Moral I. Gómez 《Journal of plant nutrition》2013,36(9):1231-1237
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
16.
The jute (Corchorus capsularis L.) cv. 3RC‐212 which is Fe‐efficient, was subjected to Fe‐deficiency stress, and the nutrient medium was examined for chemicals, when the plants became chlorotic and the pH was lowered to about 4. While phenolic acids could not be detected, DBP (dibutyl phthalate) was identified in the extract by means of TLC and HPLC. The effect of DBP and caffeic acid was studied in JRC‐212 and DBP was found to cause recovery of the plants from chlorosis in 5 days. The chemicals, PA (phthalic acid), a derivative of DBP (50 mg/1) were supplied to chlorotic plants of JRO‐632, an Fe‐inefficient jute cultivar, and both the chemicals were effective in chlorosis recovery. PA application caused more rapid greening than DBP.
Jute is the second crop species in which DBP is identified in the root exudate. The detection of DBP was first recorded in sorghum CSH‐7. 相似文献
17.
Massimo Tagliavini Adamo Domenico Rombolà Bruno Marangoni 《Journal of plant nutrition》2013,36(11):2465-2482
Roots of iron (Fe)‐efficient dicots react to Fe‐deficiency stress by strongly enhancing the ferric (Fe3+)‐reductase system and by lowering the rhizo‐sphere pH. In this study, we tested whether such adaptation mechanisms characterize pear and quince genotypes known to have differential tolerance to calcareous and alkaline soils. Two trials were performed using micropagated plants of three quince rootstocks (BA29, CTS212, and MC), three Pyrus communis rootstocks (OHxF51 and two selections obtained at the Bologna University: A28 and B21) and of two pear cultivars (Abbé Fétel and Bartlett, own‐rooted). In the first trial, plants were grown in a nutrient solution with [Fe(+)] and without [Fe(‐)] Fe for 50 days. Their root Fe‐reducing capacity was determined colorimetrically using ferrozine and FeEDTA, and Fe uptake of Fe(+) plants was estimated. In the second trial, the rhizosphere pH of plants grown in an alkaline soil was measured by a micro‐electrode. With the only exception of pears OHxF51 and A28, whose Fe‐reduction rates were similar in Fe(+) and Fe(‐) plants, the Fe‐deficiency stress resulted in a significant decrease in Fe reduction. Among the Fe(‐) plants, the two pear cultivars, OHxF51 and A28, had a higher Fe‐reducing capacity than the quince rootstocks and the cv. Abb6 F. When plants were pre‐treated with Fe, reduction rate was highest in the P. communis rootstocks, intermediate in the own‐rooted cultivars, and lowest in the quinces. Root Fe‐reducing capacity of Fe(+) plants proved to be linearly and positively correlated with Fe uptake and root proton release. Rhizosphere pH was highest in quince MC, intermediate in the other two quinces and in the cv. Abbe F., and lowest in the pear rootstocks and in the cv. Bartlett. Our results indicate that roots of pear and quinces do not increase their ability to reduce the Fe under Fe‐deficiency stress. The genotypical differential tolerance to Fe chlorosis likely reflects differences in the standard reductase system and in the capacity of lowering the pH at the soil/root interface. The determination of the root Fe‐reducing capacity is a promising screening technique for selecting pear root‐stocks efficient in taking up Fe. 相似文献
18.
《Communications in Soil Science and Plant Analysis》2012,43(3-4):305-319
Abstract The uptake and distribution of manganese (Mn) in field‐grown maize (Zea mays L.) was studied in a long‐term sewage sludge field trial on an acid sandy soil at Bordeaux. Since 1974, sewage sludge had been applied at levels of 101 dry matter (DM) ha‐1 year‐1 (SS 10) and 1001 DM ha‐1 per 2 years (SS 100) on annually cropped maize plots. Treatment with farmyard manure (FYM) at a rate of 10 t DM ha‐1 year‐1 served as unpolluted control. Five replicate plants per treatment were examined at six different growth stages. At each stage, the whole plant was separated into its different organs and the Mn distribution was determined in at least 12 different plant parts. Manganese concentrations were always higher in SS 100 plants compared to FYM and SS 10 treated plants. Significant treatment‐dependent differences occurred almost all in the roots and in the different leaf levels while we found similar Mn concentrations in the stalk and in the reproductive organs. In the different stalk levels and in the ear composites we determined low Mn concentrations with critical deficiency values in FYM and SS 10 plants while Mn concentrations in SS 100 plants were in the normal range. Soil treatment also significantly influenced the initial absorption by the roots. Despite low absolute Mn concentrations in the roots of FYM plants, the Mn transfer coefficient (plant Mn concentration/soil Mn concentration) was highest in FYM plants and lowest in SS 100 plants indicating a relatively low Mn plant availability in the sludge‐treated plots. 相似文献
19.
《Communications in Soil Science and Plant Analysis》2012,43(7-8):851-869
Abstract The objective of this study was to determine the effects of pH and ionic strength on the distribution and speciation of zinc (Zn), copper (Cu), and cadmium (Cd) in surface soil samples from two Brazilian Oxisols amended with biosolids. Soils and biosolids were equilibrated in an experimental dual‐chamber diffusion apparatus that permits the soils and biosolids to react through a solution phase via diffusion across a membrane. After equilibrium was reached, soil and biosolids samples were sequentially fractionated to identify various solid forms of Zn, Cu, and Cd. Metal concentrations in the solution phase were determined and mass balance calculated. Equilibrating pH had no major effect on Cu solubility from biosolids and, at pH range from 4 to 7, most Cu remained in the biosolids. Soluble Zn and Cd concentration increased with decreasing pH because of the increased solubility of the biosolids. Copper and Zn were primarily associated with the residual fraction and Fe oxides in one soil, but were primarily associated with chemically unstable fractions, or adsorbed to the surface of oxides, in the other soil. In both soils, Cd was primarily associated with readily bioavailable fractions. The effect of pH on the metal distribution was more evident than the ionic strength effect. Free ions were the predominant metal species in solution, especially at lower pH values. 相似文献
20.
Seedlings of two barley cultivars differing in NaCl sensitivity were treated with low (100 mM) or high (400 mM) concentration of NaCl for 6 days. Tonoplast vesicles were prepared from roots, and H+‐ATPase and H+‐transport activities associated with tonoplast were assayed. Both H+‐ATPase and H+‐transport activities in the two cultivars were increased at 100 mM NaCl. These activities also increased in the salt‐tolerant cultivar at 400 mM NaCl, but in salt‐sensitive cultivar were decreased. In vivo treatment with 10 mM Ca2+ stimulated H+‐ATPase and H+‐transport activities at two levels of NaCl, however, treatment with 105M (±) abscisic acid (ABA) inhibited these activities. From these results we propose that the increase of the vacuolar H+ pumps in barley roots reflects an adaptation to salt stress. The stimulation of HVATPase and H+‐transport activities by calcium (Ca) depends mainly on its effect in maintaining stability of membrane under salt stress. 相似文献