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1.
Three experiments were conducted in which roots of two species of Lotus were immersed for up to 40 min in complete nutrient solutions containing 6, 15 or 25 μM Al. The two species tested were L. pedunculatus cv. Grasslands Maku (Al‐tolerant) and L. corniculatus cv. Maitland (Al‐sensitive). There was an initial rapid (< 5 min) decrease in solution Al at 25 μM Al. The effect was less marked with solution Al ≤ 15 μM. The decrease in solution Al was greater in the Al‐sensitive Maitland than in the Al‐tolerant Grasslands Maku, particularly when expressed on the basis of root fresh mass and root length. Root cation‐exchange capacity (CEC) was lower in Grasslands Maku than in Maitland, viz. 23.9 vs 36.5 mmol kg‐1 dry mass. Maitland roots removed more Al from solution than did those of Maku on the basis of total exchange capacity. We propose a mechanism of Al tolerance on the basis of the results of this study and of other published information, viz. that differential Al tolerance results from differences in root CEC. Aluminum‐tolerant genotypes have roots with low CEC, and high Al activities (> 20 μM in the case of Grasslands Maku) are required to precipitate the relatively highly methylated pectins associated with low CEC. In contrast, relatively low activities of Al would precipitate the pectins in plants with roots of high CEC. This would decrease the protective capacity of the pectins, enabling the toxic, monomeric Al ions to come in contact with a number of Al‐sensitive compounds or processes in the cell wall, plasmalemma, or cell cytoplasm. 相似文献
2.
The effect of phosphorus (P) level, solution pH, aluminium (Al) level on root exocellular acid phosphatase activity of white clover (Trifolium repens L.) populations was investigated in three experiments. Lotus pedunculatus Cav. cv. Maku was also included in one experiment. Phosphatase activity increased with decreasing P and increasing Al supply, but was unaffected by the solution pH at which populations had been grown. There was usually a significant negative correlation between acid phosphatase activity and parameters measuring plant size, for plants grown at adequate P levels, but in only one of the three experiments were there significant differences between white clover populations for phosphatase activity. There was no clear correlation between the acid phosphatase activity of populations and the P status of soil from which they were collected. We conclude that root exocellular acid phosphatase activity is unlikely to be a useful character in screening for tolerance of low‐P conditions. 相似文献
3.
The effect of Al on the growth and chemical composition of onions (Allium cepa L. cv Pukekohe longkeeper), asparagus (Asparagus officinalis L. cv Lucullus) and squash (Cucurbita maxima L. cv Delica) was investigated using a low ionic strength solution‐culture technique. Onions and asparagus were sensitive to Al while squash was relatively tolerant. The dry matter yields of onion, asparagus and squash tops were reduced 50% by 5, 3, and 26 μM Al in the solution, respectively. Similarly, root dry matter yields were reduced 50% by 1, 5, and 26 μM Al, respectivley. Aluminium reduced the concentration of macro nutrients in both asparagus and onion tops but had no consistent effect on squash tops. Plant analysis and visible symptoms indicated that Al affected magnesium nutrition more than that of any other nutrient. The roots of squash showed an ability to recover from Al stress by modifying their morphology. However, this effect was insufficient to totally alleviate Al toxicity. Squash also became more sensitive to Al as the growing period progressed. These observations suggest that care is needed in using short term experiments to assess Al tolerance for some species. 相似文献
4.
The effect of varying solution calcium (Ca) and magnesium (Mg) concentrations in the absence or presence of 10 μM aluminum (Al) was investigated in several experiments using a low ionic strength (2.7 × 10‐3 M) solution culture technique. Aluminium‐tolerant and Al‐sensitive lines of wheat (Triticum aestivum L.) were grown. In the absence of Al, top yields decreased when solution Ca concentrations were <50 μM or plant Ca concentrations were <2.0 mg/g. Top and root yields decreased when solution Mg concentrations were <50 μM or plant Mg concentrations were <1.5 mg/g. There were no differences between the lines in solution or plant concentrations at which yield declined. Increasing solution Ca concentrations decreased plant Mg concentrations in the tops (competitive ion effect) but increased plant Mg concentrations in the roots of wheat. This suggests that Ca is competing with Mg when Mg is transported from the roots. Increasing solution Mg concentrations decreased plant Ca concentrations in the tops and the roots (competitive ion effect). In the roots, increasing solution Mg concentrations decreased plant Ca concentrations at a lower solution Ca concentration in the Al‐sensitive line than the Al‐tolerant line. In the presence of Al, increasing solution Ca and Mg concentrations increased yield (Ca and Mg ameliorating Al toxicity). Yield increased until the sum of the solution concentrations of the divalent cations (Ca+Mg) was 2,000 μM for the Al‐tolerant line or 4,000 μM for the Al‐sensitive line. The exception was that yield decreased when solution Mg concentrations were > 1,500 μM and the solution Ca concentration was 100 μM (Mg exacerbating Al toxicity). The ameliorative effects of solution Ca or Mg on Al tolerance were not related to plant Ca or Mg concentrations per se. 相似文献
5.
《Communications in Soil Science and Plant Analysis》2012,43(11-12):1213-1229
Abstract One proposed mechanism of aluminum (Al)‐tolerance involves the ability of plants to maintain uptake of essential mineral elements in the presence of Al. To examine this hypothesis, taro [Colocasia esculenta (L.) Schott] cultivars (cv.) Lehua maoli and Bun long were grown in hydroponic solution at six initial Al levels (0, 110, 220, 440, 890, and 1330 μM Al), and plant mineral concentrations were determined after 27 days. Increasing Al levels significantly increased Al concentrations in taro leaf blades, petioles, and roots. This increase in Al concentrations in the leaf blades as solution Al levels increased was greater for Al‐sensitive cv. Bun long compared to cv. Lehua maoli, resulting in significant interaction between Al and cultivar effects. However, no significant cultivar differences were found for Al concentrations in the petioles or roots. Increasing Al levels in solution significantly depressed concentrations of calcium (Ca), magnesium (Mg), manganese (Mn), and iron (Fe) in taro leaf blades, and significantly depressed concentrations of Ca, Mg, copper (Cu), and zinc (Zn) in taro roots. Aluminum‐induced Ca deficiency appeared to be one possible mechanism of Al phototoxicity in taro, becvasue Ca concentrations in the leaf blades and roots at the higher Al levels were within the critical deficiency range reported for taro. Significant cultivar differences were found, in which Al‐tolerant cv. Lehua maoli had significantly greater Ca and Cu concentrations in the roots, and significantly greater potassium (K) concentrations in the leaf blades across all Al levels. Our results show that Al‐tolerance in taro cultivars is associated with the ability to maintain uptake of essential mineral nutrients, particularly Ca and K, in the presence of Al. 相似文献
6.
Ten‐day‐old seedlings of four cowpea (Vigna unguiculata Walp) genotypes were subjected to six levels of aluminum (Al) (0, 74, 148, 222, 296, and 370 μM/L) to test their tolerance to Al toxicity in a nutrient solution at pH 4.0±0.1. Seedlings were grown in the presence of Al under controlled environmental conditions in a growth chamber. The nutrient solutions were replenished once a week. After 20 days, treatments were terminated and the differences in their growth patterns were compared. Standard growth parameters, such as plant growth, dry matter production, relative growth reduction in roots (RGRS) and shoots (RGRS), and root and shoot tolerance indices (RTI and STI) have been used as markers of Al toxicity. The cowpea genotypes studied exhibited a wide range of responses in their tolerance to Al. Though the genotypes were subjected to six levels of Al, a good degree of separation in their responses was observed only at the 222 μM Al/L treatment level. Therefore, this concentration was chosen to treat and compare the performances of the genotypes. The genotype Co 3 showed an increase in growth, while Paiyur 1 and other genotypes showed severe inhibitions in the presence of Al. Furthermore, for RTI and STI, Co 3 also registered its tolerance to Al by showing increased ratios in the presence of Al. Whereas, Paiyur 1 recorded severe reductions. The RGRR and RGRS data also substantiates this finding. Based on the growth parameters, the four cowpea genotypes were ranked based on their tolerance to Al: Co 3 > Co 4 > KM > Paiyur 1. Co 3 was the most Al‐tolerant genotype which performed extremely well in the presence of Al, while Paiyur 1was the most Al‐susceptible genotype. Therefore, the Al‐tolerant genotype can be used for future breeding programmes to produce Al‐tolerant genotypes, subsequently, can be recommended for acidic infertile soils in the tropics. 相似文献
7.
Screening cultivars for aluminum (Al) tolerance is often conducted in acid soils or in complete nutrient solutions. The former method lacks precise measurements of Al, and the second requires high Al concentrations because of precipitation and chelation of the Al and is less representative of the actual environmental stresses to which plants must adapt. These experiments were designed to determine Al tolerance of wheat (Triticum aestivum L. em Thell) and sorghum (Sorghum bicolor L. Moench) using incomplete solutions with very low Al concentrations. Six wheat and five sorghum cultivars were screened for Al tolerance in solution culture with 0 to 10 μM Al and only Ca, K, Mg, NO3, and Cl in the solutions. Plants were subjected to the solutions for 4 d, and the change in relative root length was measured. Solution Al levels and pH were measured after the termination of the experiments. ‘Atlas’ 66 and ‘Stacy’ were the most tolerant wheat cultivars ('Atlas 66’ = ‘Stacy’ ≥ ‘Monon’ ≥ ‘Scout 66’ ≥ ‘Arthur 71’ = ‘Oasis'). The wheat cultivars were effectively separated on a genetic response basis at 2 μM Al. Sorghum cultivars were uniform in their Al tolerance, but did show some separation at 1 μM Al (SC56 > Tx430 > ‘Funk GS22DR’ > SC283 = SC599). The pH and Al variations did not account for any of the differences observed, indicating that root length differences were caused by genetic control of response to high Al. 相似文献
8.
Ten‐day‐old seedlings of 22 rice (Oryza sativa.L) cultivars originated from various tropical countries were subjected to six levels of aluminum (Al) [0, 74, 148, 222, 296, and 370 μM] to test their tolerance to Al toxicity in nutrient solutions at pH 4.0±0.l. Seedlings were grown in the presence of Al under controlled environmental conditions in growth chambers. The nutrient solutions were replenished once a week. After 30 days, treatments were terminated and the differences in their growth patterns were compared. Standard growth parameters such as plant growth, dry matter production, relative growth reduction in roots (RGRS) and shoots (RGRS), root tolerance index (RTI) and shoot tolerance index (STI) have been used as markers of Al toxicity. Rice cultivars studied exhibited wide range of responses in their tolerance to Al. Though, the rice cultivars were subjected to six levels of Al, a good degree of separation in their responses was observed only at 222 μM Al. Therefore, this concentration was chosen to analyze and compare the performances of the cultivars. Further, only six cultivars showed significant changes in their expression in the presence of Al compared to control, and so data have been presented only for those cultivars for clarity. The cultivars BW 196, Bhura Rata, Basmati 370 and Co 37 recorded increases in growth, while Damodar and ADT 36 showed severe inhibitions in the presence of Al. Furthermore, in RTI and STI also Co 37 and Basmati 370 registered their tolerance to Al by showing increased growth in the presence of Al. Whereas, Damodar and ADT 36 recorded severe reductions. The RGRR and RGRS data also substantiates this finding. Based on the growth parameters, the six rice cultivars were ranked based on their tolerance to Al: Co 37 > Basmati 370 > BW 196 > Bhura Rata > Damodar > ADT 36. Co 37 and Basmati 370 are the two most tolerant cultivars which performed extremely well in the presence of Al, and Damodar and ADT 36 are the most susceptible cultivars. Therefore, the Al‐tolerant cultivars can be used for future breeding programes to develop Al‐tolerant, cultivars that subsequendy can be recommended for planting in acidic, infertile soils of the tropics. 相似文献
9.
Al and Pb tolerance of different ectomycorrhizal fungi was tested in Petri dishes divided into three compartments. One compartment contained nutrient solution supplemented with Al or Pb but without P to avoid precipitation of Al or Pb phosphates. Phosphate was supplied in the agar compartment while a third compartment served as control containing nutrient solution without P. The tested ectomycorrhizal fungal species and isolates varied greatly in their Al and Pb tolerance. A more than 50% growth reduction was observed at 2000 μM Al in Paxillus involutus MAI but already at 200 μM in P. involutus NAU and P. involutus 533. In contrast, growth of Pisolithus tinctorius 956 appeared to be stimulated by Al. Al tolerance therefore decreased in the following order: P. tinctorius 956 > P. involutus MAI > P. involutus NAU, P. involutus 533. To test the effect of agar on Al tolerance, P. involutus MAI was grown with agar in all three compartments. In presence of agar, even 2000 μM Al had no effect on growth. Lead at concentrations of 1 and 10 μM Pb had no significant effect on fungal growth. A more than 50% decrease of mycelial surface area occurred at 500 μM Pb in P. involutus MAI and P. involutus 533 and at 100 μM Pb in P. involutus NAU and P. tinctorius 956. Pb tolerance therefore decreased in the following order: P. involutus MAI, P. involutus 533 > P. involutus NAU, P. tinctorius 956. Divided Petri plates appear to be a valuable tool to test metal tolerance of fungi as complexation of the metals by agar or precipitation with P are avoided. The results indicate that some ectomycorrhizal fungi may be more sensitive to Al and Pb than previously reported. 相似文献
10.
D. M. Wheeler 《Journal of plant nutrition》2013,36(5):949-954
The effect of aluminium (Al) on the relative yield of plants grown from seeds of ryegrass (Lolium perenne L.) or white clover (Trifolium repens L.) and either tillers (ryegrass) or stolon tip cuttings (white clover) were investigated using a low ionic strength (2.7 x 10‐3 M) solution culture technique. In ryegrass, plants grown from tillers had higher relative yields than plants grown from seedlings in the tops when solution Al concentrations were greater than 16 μM and in the roots when solution Al concentrations were greater than 7 μM. In white clover, relative yields in the tops and roots plants were higher in plants grown from stolon tip cuttings than from seedlings when solution Al concentrations were greater than 10 μM. There were no significant cultivar effects. The results indicate that plants used in Al‐tolerance experiments can be grown from seed or vegetatively propagated, provided solution Al rates are adjusted to reflect differences in Al tolerance. 相似文献
11.
《Communications in Soil Science and Plant Analysis》2012,43(11-12):1197-1221
Abstract Aluminum (Al) toxicity is one of the major factors limiting plant growth in acid soils. To determine the response of taro [Colocasia esculenta (L.) Schott] to Al‐toxicity, cultivars (cv.) Lehua maoli and Bun long were grown in hydroponic solution at six initial levels of Al (0, 110, 220, 440, 890, and 1330 uM Al). Increasing Al levels significantly depressed fresh and dry weights of taro leaf blades, petioles, and roots, as well as leaf areas and root lengths. No significant cultivar differences were found for plant dry weights. However, significant cultivar differences were found for expansion growth parameters, with cv. Lehua maoli exhibiting greater leaf fresh weights and root lengths in the presence of Al, compared to cv. Bun long. Apparently, differential response of taro cultivars to Al is related to the ability of the Al‐tolerant cultivar to maintain water uptake and cell expansion in the presence of Al. The initial solution Al level that resulted in the greatest separation of growth differences between taro cultivars in their response to Al was 890 μM Al. 相似文献
12.
Eva Borghesi Giulia Carmassi Maria C. Uguccioni Paolo Vernieri Fernando Malorgio 《Journal of plant nutrition》2013,36(5):677-690
Abstract Fine fescues (Festuca spp.) are generally considered acid tolerant compared to other cool‐season turfgrasses. However, there is little information on aluminum (Al) tolerance of fine fescues at both the species and cultivar levels. The objectives of this study were to identy cultivars of fine fescues with superior ability to tolerate Al, and compare the Al tolerance of endophyte infected and endophyte‐free cultivars in Al tolerance. A total of 58 cultrvars of fine fescues belonging to five species or subspecies [14 hard fescue (F. longifolia Thuill), 25 Chewings fescue (F. rubra L. ssp. commutata Gaud), 15 strong creeping red fescue (F. rubra L. ssp. rubra), two slender creeping red fescue (F. rubra L. ssp. trichophylla), and two sheep fescue (F. ovina L.)] were selected from the 1993 National Fineleaf Fescue Test and screened under greenhouse conditions using solution culture, sand culture, and acid Tatum soil (Clayey, mixed, thermic, typic, Hapludult). The acid Tatum soil had 69% exchangeable Al and a pH of 4.4. An Al concentration of 640 μM and a pH of 4.0 were used in solution culture and sand culture screening. The grasses were seeded and grown for three weeks before harvesting. Aluminum tolerance was assessed by measuring relative root length, shoot length, root weight, shoot weight, and total dry matter. Differences in Al tolerance were identified at both the species and cultivar level based on relative growth were as follows: i) hard fescue and Chewings fescue were more Al tolerant than strong creeping red fescue; ii) within species or subspecies, significant differences were found among cultvars of Chewings fescue, strong creeping red fescue, slender creeping red fescue, and sheep fescue; whereas no difference was observed among the hard fescue cultivars; and iii) the cultivars containing endophyte exhibited greater Al tolerance compared the eudophyte‐free cultivars. The results indicate that fine fescues vary in Al tolerance and there is potential to improve Al tolerance with breeding and to refine their management recommendations regarding soil pH. 相似文献
13.
Ozone (O3) toxicity is a potential yield‐limiting factor for soybean (Glycine max L. Merr.) in the United States and worldwide. The most economical solution to the problem is to use O3‐tolerant cultivars. Thirty‐four cultivars and 87 near‐isogenic lines (NILS) of soybean were screened for O3 tolerance in a fumigation chamber (250 ppb for three hrs). Most tolerant cultivars tested were ‘Cloud’, ‘T‐276’, ‘T263’, and ‘Kindu’. Moderately tolerant cultivars included ‘Davis’, ‘T‐210’, and ‘Elton’. Most sensitive cultivars were ‘Corsoy 79’, ‘Noir’, and ‘Midwest’. The original ‘Clark’ cultivar was not tested, but ‘Clark 63’ tended to be more tolerant than ‘Harosoy’. The aluminum (Al)‐tolerant ‘Perry’ cultivar also tended toward greater O3 tolerance than the Al‐sensitive ‘Chief’, as observed earlier. Our rankings of ‘Hark’ as moderately sensitive and ‘Davis’ as moderately tolerant are also in agreement with earlier reports. Among NILS, the order of O3 tolerance was generally Williams>Clark>Harosoy, but differences were also observed within these parental groups. For example, L68–560 was more tolerant than some other NILS of ‘Harosoy’. ‘L76–1988’ appeared more tolerant to O3 than other NILS of ‘Williams’, but all ‘Williams’ NILS were more tolerant than most NILS of ‘Harosoy’ and ‘Clark’. Ozone‐tolerant and ‐sensitive soybean cultivars or NILS identified in our study may be useful tools in studies on mechanisms of 03 tolerance and differential 03 tolerances in plants and in the development of ameliorative measures. 相似文献
14.
192 sites covering the main soil types in Northern Ireland were analysed for numbers and effectiveness of clover and Lotus rhizobia, and chemical properties. Peat sites were generally highly acid (pH <5.5) and mineral sites near neutral (pH 5.5–7.8). Clover rhizobia were generally absent from peat sites and present in mineral sites as large populations (> 106 g?1 dry soil). 79% of isolates were effective on T. repens var. Grasslands Huia. Lotus rhizobia were generally absent from peat sites, less often present than clover rhizobia in mineral sites, and as smaller populations. They were mainly effective on L. pedunculatus var. G4705 and were all of the slow-growing type belonging to the genus Bradyrhizobium. Numbers of clover rhizobia were significantly correlated with soil pH, exchangeable Ca, base saturation and Al saturation, but effectiveness of clover rhizobia and numbers of Lotus rhizobia were not correlated with any soil chemical property. 相似文献
15.
Toxic effects of aluminium (Al) on root tips are considered to decrease export of cytokinins to shoots, and deficiency of cytokinins has been made responsible for Al‐induced inhibition of shoot growth. But no experimental data on the influence of Al on endogenous cytokinin levels in higher plants have been reported. In this study, the endogenous levels of zeatin riboside (ZR) and dihydrozeatin riboside (DHZR) of roots, stems, and leaves of two bean cultivars (Phaseolus vulgaris L. cv Contender and cv Strike) exposed to Al in continuously flowing nutrient solution (pH 4.5) was analysed. The supply of a high Al concentration (sum of monomeric Al species, 127 μM) caused severe inhibition of root elongation in both cultivars. The cv Strike was more affected by both Al‐induced mineral nutrient disorders and Al‐induced alteration of leaf water relationships. In both cultivars Al‐supply significantly increased ZR and DHZR. Leaves of Al‐treated plants exhibited a more than three times higher concentration of ribosylated cytokinins than controls. Nevertheless, stomatal resistance was significantly increased by Al in both cultivars. Our results support the hypothesis that Al affects plants not by inducing deficiency of cytokinins but of some other factor necessary for the manifestation of cytokinin action. 相似文献
16.
C. D. Foy 《Journal of plant nutrition》2013,36(10-11):1381-1394
Durum wheat, Triticum durum Desf., is reportedly more sensitive to aluminum (Al) toxicity in acid soils than hexaploid wheat, Triticum aestivum L. em. Thell. Aluminum‐tolerant genotypes would permit more widespread use of this species where it is desired, but not grown, because of acid soil constraints. Durum wheat germplasm has not been adequately screened for acid soil (Al) tolerance. Fifteen lines of durum wheat were grown for 28 days in greenhouse pots of acid, Al‐toxic Tatum subsoil at pH 4.5, and non‐toxic soil at pH 6.0. Aluminum‐tolerant Atlas 66 and sensitive Scout 66 hexaploid wheats were also included as standards. Based on relative shoot and root dry weight (wt. at pH 4.5/wt. at pH 6.0 X 100), durum entries differed significantly in tolerance to the acid soil. Relative shoot dry weight alone was an acceptable indicator of acid soil tolerance. Relative dry weights ranged from 55.1 to 15.5% for shoots and from 107 to 15.8% for roots. Durum lines PI 195726 (Ethiopia) and PI 193922 (Brazil) were significantly more tolerant than all other entries, even the Al‐tolerant, hexaploid Atlas 66 standard. Hence, these two lines have potential for direct use on acid soils or as breeding materials for use in developing greater Al tolerance in durum wheat. Unexpectedly, the range of acid soil tolerance available in durum wheat appears comparable to that in the hexaploid species. Hence, additional screening of durum wheat germplasm for acid soil (Al) tolerance appears warranted. Durum lines showing least tolerance to the acid soil included PI 322716 (Mexico), PI 264991 (Greece), PI 478306 (Washington State, USA), and PI 345040 (Yugoslavia). The Al‐sensitive Scout 66 standard was as sensitive as the most sensitive durum lines. Concentrations of Al and phosphorus were significantly higher in shoots of acid soil sensitive than in those of tolerant lines, and these values exceeded those reported to cause Al and phosphorus (P) toxicities in wheat and barley. 相似文献
17.
D. M. Wheeler 《Journal of plant nutrition》2013,36(5):955-958
The aluminium (Al) tolerance of white clover (Trifolium repens L.) lines that had either long or short root hair lengths were evaluated in low ionic strength (2.7 x 10‐3 M) solution culture. Absolute yield of the long root hair length plants was greater than the short root hair length plants at all Al rates by, on average, 34%. However, increasing root hair length had no significant (P<0.05) effect on relative Al tolerance. 相似文献
18.
Genetic variability for responses to short‐ and long‐term salt stress in vegetative sunflower plants
Dolores Bustos Leandro Ismael Ortega Alicia Córdoba Abelardo Vegetti Edith Taleisnik 《植物养料与土壤学杂志》2012,175(6):882-890
Sunflower (Helianthus annuus L.) has been rated as moderately salt‐resistant, and variability for salt resistance has been detected within this crop. However, variability in salt‐resistance mechanisms has not been assessed. Osmotic tolerance, the relation of salt resistance with whole‐plant Na+ and K+ distribution and tissue Na+ tolerance were investigated in several sunflower inbred lines. Plants were grown under controlled conditions, in pots with sand and perlite irrigated with salinized (NaCl, –0.65 MPa) nutrient solution. Osmotic tolerance was assessed from the initial effects of the salt treatment on plant elongation in eleven sunflower lines. Long‐term salinity responses were evaluated in four of those lines, by assessing whole‐plant growth. A principal components analysis (PCA) was run on relative‐to‐control growth data, and this information was used to establish a relative resistance ranking, which indicated lines HAR2 > HAR1 > HA64 > HAR5. Osmotic tolerance was observed in HA64 and HAR2. The lines showed different degrees of Na+ accumulation, it was very low in some of them, but relative salt resistance was not associated to this trait. Tissue Na+ tolerance was deduced by comparing the percentage of dead leaves as a function of leaf blade Na+ accumulation, and it was higher in HAR1 than in the rest. These results indicate that variability for salt‐resistance mechanisms exists in sunflower. Osmotic tolerance and tissue Na+ tolerance were detected in different lines, highlighting that such variability may be exploited for increasing salt resistance in this crop. 相似文献
19.
Soil acidity is often associated with toxic aluminum (Al), and mineral uptake usually decreases in plants grown with excess Al. This study was conducted to evaluate the effects of Al (0, 35, 70, and 105 μM) on Al, phsophorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn,) and copper (Cu) uptake in shoots and roots of sorghum [Sorghum bicolor (L.) Moench, cv. SC283] colonized with the vesicular‐arbuscular mycorrhizal (VAM) fungi isolates Glomus intraradices UT143–2 (UT143) and Glomus etunicatum UT316A‐2 (UT316) and grown in sand (pH 4.8). Mycorrhizal (+VAM) plants had higher shoot and root dry matter (DM) than nonmycorrhizal (‐VAM) plants. The VAM treatment had significant effects on shoot concentrations of P, K, Ca, Fe, Mn, and Zn; shoot contents of P, S, K, Ca, Mg, Fe, Mn, Zn, and Cu; root concentrations of P, S, K, Ca, Mn, Zn, and Cu; and root contents of Al, P, S, K, Ca, Mg, Fe, Mn, Zn, and Cu. The VAM effects on nutrient concentrations and contents and DM generally followed the sequence of UT316 > UT143 > ‐VAM. The VAM isolate UT143 particularly enhanced Zn uptake, and both VAM isolates enhanced uptake of P and Cu in shoots and roots, and various other nutrients in shoots or roots. 相似文献
20.
This study compares the effect of aluminum (Al) on the shoot morphology, root distribution and plant chemical content of selections made for Al tolerance and an unselected population of Huia white clover (Trifolium repens L.). Seedlings from the two seed sources were sown into trays of soil to which had been added 400 μg Al/g soil as aluminum sulphate. The two seed sources were, (1) progeny from a polycross of genotypes previously selected for Al tolerance from the cultivar Huia and, (2) a previously unselected accession of Huia. After selection of genotypes capable of producing large shoots when grown in soil containing 400 μg g‐1 added Al, plants were grown in artificial soil profiles where soil Al content increased with depth. Selections from first generation Al‐tolerant germplasm were smaller leaved, with more leaves per unit length of stolon, with larger stolons, heavier shoots and a slightly deeper root distribution, but lower root/shoot ratio than selections from previously unselected germplasm. The proportion of root weight below 100 mm (i.e., the proportion of root growing in Al‐toxic soil) was poorly related to other characters measured. From an analysis over all 100 genotypes tested, proportion of root weight below 100 mm was significantly (P <0.05) but weakly (r=0.19) correlated with shoot [potassium/(calcium + magnesium) (K/(Ca + Mg))] ratio. Selection for Al tolerance in white clover can cause associated changes in other plant characters. 相似文献