两种冬小麦对铝毒响应的敏感性差异研究

A experiment was carried to evaluate the effects of Al on growth, accumulations of free proline and amino acid in 2 wheat cultivars (Triticum aestivum L.), Yangmai No.5 and Jian 864, differing in Al sensitivity. Plants grew initially in a nutrient solution without Al for 13 days before the addition of Al and finally in a nutrient solution containing 0.5mmol Al (L^-1) for 19 days. The results showed that there were marked decreases in dry weight, relative growth rate (RGR) and net assimilation rate (NAR) of Al-treated seedlings compared with control plants. The Al effects were more evident in Yangmai No.5 than Jian 864. Leaf area ratio(LAR) was little affected by Al. RGR was highly correlated with NAR rather than LAR. Aluminum increased the concentrations of free proline and total free amino acid in shoots of both the cultivars. The increases were greater in Yangmai No.5 than in Jian 864. The percentage of free proline in total amino acid in shoots was not affected by Al treatment. It was possible that accumulation of proline was merely a symptom of Al injury. The concentrations of total nitrogen in Al-treated plants did not significantly differ from those of control plants. Nitrate reductase activity (NRA) in leaves was severely decreased by Al, and a greater decrease was noted in Yangmai No.5 than in Jian 864, but NRA in roots of both the cultivars was not affected. The decreases in NRA might be an indirect (accumulation of amino acid) rather than a direct result of Al toxicity.     

Effects of low aluminium levels on growth and nutrient relations in three rice cultivars with different tolerances to aluminium

Reports on varietal diversity of upland rice in relation to relatively low aluminium (Al) levels are limited. Therefore, effects were examined of 35, 70, and 140 μM Al on plant growth and uptake of macro‐ and micro‐nutrients (K, P, Ca, Mg, Fe, Zn, Cu, and Mn) and their distribution in three upland rice (Oryza saliva L.) cultivars (BG35, DA14, and IR45) with different Al sensitivity. After an initial growth period of 5 days without Al, the plants were grown for 21 days in nutrient solutions containing Al at pH 4.1. Cultivar BG35 showed the highest and IR45 the lowest tolerance to Al when fresh weights of shoots or roots were considered. Except for IR45 at 140 μM Al, total dry weight was unaffected by Al, and the cultivars could not be clearly distinguished with respect to Al tolerance. Net Al uptake rate was higher in Al tolerant BG35 than in DA14 or IR45. Conversely, in IR45 the absorbed Al was rapidly transported to the shoots and accumulated there. In BG35, net P and Ca uptake rates in Al‐treated plants were high enough to maintain the P and Ca status of the shoots at all Al levels. Irrespective of Al sensitivity, there was a general depression of internal Mg concentration in Al‐reated plants. The Fe, Zn, Cu, and Mn concentrations of the plants were not negatively affected by Al in any of the cultivars.     

Varietal diversity of upland rice in sensitivity to aluminium

A rapid and simple nutrient addition technique was used for evaluating Al tolerance of six local upland rice (Oryza sativa L.) cultivars (BG35, BR21, DA25, DA26, DA14, and DA22) from Bangladesh and three IRRI rice, IR46, IR97, and IR45, cultivars from the Philippines. The plants were grown for 21 days with Al (0 μM, 140 μM, 280 μM or 560 μM) at pH 4.1. The roots were more affected by Al than the shoots. In rating cultivars for Al sensitivity, relative shoot weight (RSW) was found to be the best parameter due to the severe damage of the roots, irrespective of Al sensitivity. The cultivars were rated as Al tolerant (BG35, BR21, DA25, and DA26), mid‐tolerant (DA14, DA22, and IR46) and sensitive (IR97 and IR45) . More Al was retained in the roots of tolerant cultivars than in the mid‐tolerant or sensitive cultivars. In shoots, the Al concentration of tolerant cultivars was less than in the mid‐tolerant or in the sensitive cultivars and the inhibition of growth was proportional to Al concentration irrespective of Al tolerance. Therefore, the variation among cultivars in Al sensitivity could be related to the capacity of roots to retain Al from transport to the shoots.     

Effect of aluminium and calcium on growth of wheat seedlings and germination of seeds

Two separate experiments were conducted to investigate the aluminium (Al) and calcium (Ca) effects on wheat seedling growth and on seed germination. Wheat (Tritcum aestivum L, cs Yangmai No. 5) seedlings were grown for a 15‐day period and treated with 0.5 mM Al with low Ca (1 mM Ca) or high Ca (5 mM Ca). The growth of seedlings was signficantly inhibited by Al. Supplement of Ca improved the growth of Al‐treated plants, increased dry matter weight of plant and leaf area, and decreased shoot/root ratio. This showed that Ca ameliorated Al toxicity in wheat. In experiments on seed germination, Al concentrations less than 2 mM in the germinating medium had little or no visible effect on length of shoot and root of germinating seed. The germinating rate of seed was not affected significantly by Al, when Al concentrations lower than 5 mM Al. The addition of 3 mM Ca did not increase the length of shoot and root and germination rate of seeds. Both pretreatments with 6 mM Ca and 1 μM GA had no significant effect on the length of shoot and root and amylolytic activity of Al‐treated germinating seeds. No significant differences were found in the total amylolytic activity in Al‐treated and control seeds two days and five days after germination. The results of Al and Ca effects on seedlings and seed germination showed that Al‐toxicity on germinating seeds was different from on seedling growth. The high concentrations of Al inhibit growth of roots and shoots of germinating seeds by other toxicity mechanism rather than interaction of Al with Ca and mobilization of carbohydrate reserves.     

不同类型小麦品种干物质积累与产量形成的关系

在高产条件下,冬性春性类型小麦品种各自适期播种,相对早播的冬性半冬性类型的总干物质积累量(简称DMA,后同)高于春性类型;生育前期冬性、半冬性的DMA高于春性,后期春性半冬性高于冬性.茎秆光合产物输出率、成熟期籽粒干重占单株总干重的百分率表现为春性>半冬性>冬性,而基秆干重所占的百分率则呈相反趋势.同期播种,总DMA及籽粒产量都有春性高于冬性、半冬性的趋势.春性及半冬性品种的籽粒干重日增长量和籽粒相对生长率都明显高于冬性品种.因而春性及半冬性品种单株粒重大,经济产量高.本文提出在冬性春性类型品种交叉地区,     

Aluminium sensitivity of two upland rice cultivars at various levels of nutrient supply

Two upland rice (Oryza sativa L.) cultivars with high (IR45) and low (BG35) aluminium (Al) sensitivity were selected to investigate the influence of Al on growth and uptake and distribution of macronutrients [potassium (K), phosphorus (P), calcium (Ca), and magnesium (Mg)] when the plants were grown at various levels of nutrient supply. The plants were grown for 21 days with or without 140 μM Al at pH 4.1. Nutrients were supplied with 2.5, 5.0, 10, or 15% relative increase/day relative nutrient addition rate (RNR), according to a nutrient supply program. In this range of nutrient supply rates, the degree of Al sensitivity in the two rice cultivars was not markedly affected, except for root growth in BG35 that was more inhibited at low RNRs than at high RNRs. Regardless of nutrient supply rate, Al was mainly confined to the roots in both cultivars. However, the concentrations of Al in the shoots was consistently lower in BG35 than in IR45. Different Al sensitivity in BG35 and IR45 was associated with different influence on uptake and distribution of P and Ca. Uptake of Mg was drastically inhibited by Al at all nutrient supply levels in both cultivars. Uptake and distribution of K were not negatively affected by Al.     

Accumulation of amino acids,proline, and carbohydrates in response to aluminum and manganese stress in maize

Synthesis of amino acids, proline, and carbohydrates was studied in roots and shoots of 5 maize accessions, differing in aluminum (Al) and manganese (Mn) tolerance, in response to Al and Mn stress at the seedling stage in solution culture. The concentrations of these metabolites increased in roots and shoots of the seedlings in the nutrient solution with added Al (0.22 mM), and Mn (2.0 mM). Both Al and/or Mn tolerant and non‐tolerant accessions accumulated more metabolites under stress than control. Generally, the tolerant accessions accumulated more solutes than the non‐tolerant maize accessions examined.     

Aluminium‐induced increase of zeatin riboside and dihydrozeatin riboside in Phaseolus vulgaris L. cultivars

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.     

不同Zn浓度对黑麦草根分泌物、根际Zn形态及植物Zn蓄集的影响

A glasshouse experiment was conducted using a root-bag technique to study the root exudates, rhizosphere Zn fractions, and Zn concentrations and accumulations of two ryegrass cultivars (Lolium perenne L. cvs. Airs and Tede) at different soil Zn levels (0, 2, 4, 8, and 16 mmol kg-1 soil). Results indicated that plant growth of the two cultivars was not adversely affected at soil Zn level≤8 mmol kg-1. Plants accumulated more Zn as soil Zn levels increased, and Zn concentrations of shoots were about 540 /μg g-1 in Aris and 583.9μg g-1 in Tede in response to 16 mmol Zn kg-1 soil. Zn ratios of shoots to roots across the soil Zn levels were higher in Tede than in Airs, corresponding with higher rhizosphere available Zn fractions (exchangeable, bound to manganese oxides, and bound to organic matter) in Airs than in Tede. Low-molecular-weight (LMW) organic acids (oxalic, tartaric, malic, and succinic acids) and amino acids (proline, threonine, glutamic acid, and aspartic acid, etc.) were detected in root exudates, and the concentrations of LMW organic acids and amino acids increased with addition of 4 mmol Zn kg-1 soil compared with zero Zn addition. Higher rhizosphere concentrations of oxalic acid, glutamic acid, alanine, phenylalanine, leucine, and proline in Tede than in Airs likely resulted in increased Zn uptake from the soil by Tede than by Airs. The results suggested that genotypic differences in Zn accumulations were mainly because of different root exudates and rhizosphere Zn fractions.     

Aluminium-induced callose formation in root tips of Norway spruce (Picea abies (L.) Karst.)

The objective of this study was to examine whether aluminium (Al) induces callose formation in roots of Norway spruce as it does in soybean. Spruce seedlings were grown in Al-free nutrient solution under controlled conditions in a growth chamber at pH 3.8. After 21 days 170 μM Al was added or not (controls) to the complete nutrient solution (molar Ca/Al ratio: 0.75). Callose could be detected in outer root-tip cells of Al-treated plants within 3 h, using fluorescence microscopy after staining with aniline blue. Prolonged Al treatment up to 24 h increased both the density of the callose deposits and the number of affected cell layers. Control plants showed no comparable callose deposits. Ultrastructural examinations showed cell-wall appositions in Al-treated root cells but not in controls. The possible implications of Al-induced callose formation for nutrient and water uptake by roots are discussed.     

铝胁迫下不同小麦基因型根际pH的变化、NH4+和NO3-吸收及还原与其耐铝性的关系

以耐Al性明显差异的 2个小麦基因型为材料 ,采用溶液培养试验和动力学方法研究了根际 pH变化、NH4+和NO3- 的吸收以及NO3- 还原与其耐Al性的关系。结果表明 ,A1胁迫下鉴 86.4(耐性基因型 )比扬麦 5号 (敏感基因型 )能维持较高的根际 pH值 ,当溶液 pH值下降到最低时 ,前者比后者高 0.23个pH单位。吸收动力学研究表明 ,鉴 86-4在无Al和有Al胁迫时对NO3- 的吸收速率和亲和力大于扬麦 5号 ;而对NH4+的吸收速率和亲和力却小于扬麦 5号。Al还降低叶片和根系的硝酸还原酶活性 ,但鉴 86.4的叶片和根系硝酸还原酶活性均高于扬麦 5号。此外 ,在Al胁迫下 ,植株体内游离脯氨酸含量迅速提高 ,但扬麦 5号积累量高于鉴 86.4。鉴 86.4具有较高的耐Al能力可能与其在Al胁迫下对NO3- 的吸收速率、亲和力以及硝酸还原酶活性较高 ,而对N4+的吸收速率和亲和力较低 ,从而能维持较高的根际 pH值有关     

Tolerance of barley cultivars to an acid,aluminum‐toxic subsoil related to mineral element concentrations in their shoots

Abstract

Barley, Hordeum vulgare L., is extremely sensitive to excess soluble or exchangeable aluminum (Al) in acid soils having pH values below about 5.5. Aluminum tolerant cultivars are needed for use in rotations with potatoes which require a soil pH below 5.5 for control of scab disease. They are also potentially useful in the currently popular “low input, sustainable agriculture (LISA)”; in which liming even the plow layer of soil is not always possible or cost effective, or in situations where surface soils are limed but subsoils are acidic and Al toxic to roots. Ten barley cultivars were screened for Al tolerance by growing them for 25 days in greenhouse pots of acid, Al‐toxic Tatum subsoil (clayey, mixed, thermic, typic Hapludult) treated with either 750 or 4000 μg?g^‐1 CaCO₃ to produce final soil pH values of 4.4 and 5.7, respectively. Based on relative shoot dry weight (weight at pH 4.4/weight at pH 5.7 X 100), Tennessee Winter 52, Volla (England), Dayton and Herta (Denmark) were significantly more tolerant to the acid soil than Herta (Hungary), Kearney, Nebar, Dicktoo, Kenbar and Dundy cultivars. Relative shoot dry weights averaged 28.6% for tolerant and 14.1% for sensitive cultivar groups. Comparable relative root dry weights were 41.7% and 13.7% for tolerant and sensitive cultivars, respectively. At pH 4.4, Al concentrations were nearly three times as high in shoots of sensitive cultivars as in those of the tolerant group (646 vs. 175 μg?g^‐1), but these differences were reduced or absent at pH 5.7. At pH 4.4, acid soil sensitive cultivars also accumulated phosphorus concentrations that were twice as high as those in tolerant cultivars (1.2% vs. 0.64%). At pH 5.7, these P differences were equalized at about 0.7% for both tolerant and sensitive groups. At pH 4.4, shoots of the Al‐sensitive cultivar Nebar contained 1067 μg?g^‐1 Al and 1.5% P. Concentrations of Al and P in the shoots of acid soil sensitive cultivars grown at pH 4.4 exceeded levels reported to produce toxicity in barley. The observed accumulation of such concentrations of Al and P in the shoots of plants grown under Al stress is unusual and deserves further study.     

Effects of low aluminum activity in nutrient solutions on the organic acid concentrations in maize plants

The effects of low aluminum (Al) activity in nutrient solution on the concentrations of organic acids in two cultivars of maize (Zea mays L.), HS7777 Al‐sensitive and C525‐M Al‐tolerant, were studied. Aluminum stress increased total organic acid concentration in the roots and in the shoots for both cultivars. The relative increase of t‐aconitic, citric, formic, malic, and quinic acids was higher in the roots than in the shoots for both cultivars. The concentrations of c‐aconitic, isocitric, malonic, oxalic, and succinic organic acids were reduced by Al stress, principally for C525‐M. There were no consistent differences in organic acid concentrations between the cultivars to discriminate Al tolerance. The Al tolerance for C525‐M may be justified by lower Al concentrations in the root tips where cellular division takes place and/or by higher excretion of organic acids from roots to the rhizosphere for detoxification of Al by chelation.     

Effect of Salinity on Growth of Twelve Cultivars of the United Arab Emirates Date Palm

To successfully use salt water for crop production and start a breeding program, more information is needed about the response of salt‐tolerant plants to saline environments. The objective of this experiment was to test the growth of 12 cultivars of the United Arab Emirates date palm seeds at four sodium chloride (NaCl) levels. The experiment was a randomized complete block design with three replicates. Optimal growth was found at control and 3000 ppm of NaCl. Relative growth rate (RGR), biomass, and number of leaves (NL) decreased significantly by increasing salinity. Increased NaCl leads to significant decreases in potassium (K⁺), magnesium (Mg²⁺), and calcium (Ca²⁺) contents of plants. The Na/K ratios were lower in shoots than in roots. ‘Lulu,’ ‘Fard,’ ‘Khnaizi,’ ‘Nabtat Safi,’ and ‘Razez’ cultivars showed greater RGR and biomasses, whereas ‘Khnaizi,’ ‘Mesally,’ and ‘Safri’ had greater Na/K ratios than others in the control indicating greater Na⁺ discriminations from plant parts.     

小麦苗期氮素吸收利用效率差异及聚类分析

【目的】氮肥过量施用,不仅造成氮素大量流失,还增加了农业生产成本,对生态环境带来了巨大的威胁。筛选和培育氮高效小麦品种是提高氮肥利用率、 降低环境污染风险的有效途径。本文通过对44个小麦品种苗期性状的考察,初步筛选出具有氮高效潜力的小麦品种。【方法】利用循环营养液培养方法,研究了安徽省44个小麦品种(系)在正常氮(5 mmol/L)和高氮(45 mmol/L)条件下苗期氮素吸收利用效率的差异。采用隶属函数法将评价指标数据进行标准化,区间为[0,1];而后采用客观赋权法将标准化后的数据整合成一个无量纲的综合值,最后基于综合值运用最短距离法、 欧氏距离平方聚类分析方法,将44个小麦品种划分成不同的氮效率类型。【结果】在两种供氮水平下,不同小麦品种的茎叶干重、 根干重、 叶面积、 茎叶氮累积量和根氮累积量存在显著性差异,其变异系数分别在27.9%～33.7%和21.5%～32.8%之间,可作为小麦苗期氮效率的评价指标。小麦苗期氮效率综合值在正常氮和高氮水平下分别在0.053～0.920和0.001～0.853之间,其中鉴76在正常氮和高氮条件下的氮效率综合值均大于80%。通过隶属函数氮效率综合值及其聚类分析,将44个供试小麦品种分为氮高效型、 氮中效型和氮低效型三类;其中扬麦16和鉴76在正常氮和高氮条件下均表现为高效型,皖麦68、 F60501-4、 鉴62和安农1026只在高氮条件下表现为高效型。氮高效型、 氮中效型、 氮低效型小麦品种在正常供氮和高氮条件下分别占供试品种总数的4.54%、 54.55%、 40.91%和13.63%、 38.64、 47.73%。【结论】在正常供氮和高氮条件下,44个供试小麦品种的茎叶氮累积量、 茎叶干重、 根部氮累积量、 根部干重和叶面积存在显著性差异,可以作为小麦苗期氮效率评价指标;初步确定扬麦16和鉴76为正常供氮和高氮条件下的氮高效型品种,皖麦68、 F60501-4、 鉴62和安农1026 为高氮条件下的氮高效型品种。     

Sensitivity of soft red winter wheat cultivars to chlorate‐induced toxicity

The use of chlorate as a nitrate analogue to screen soft red winter wheat (Triticum aestivum L.) cultivars for differences in nitrate reductase activity (NRA) was studied by adding potassium chlorate to a hydroponic nutrient solution in which wheat seedlings were growing. After 14 days, leaf symptoms indicating chlorate‐induced toxicity were rated. It was hypothesized that wheat plants which were susceptible to chlorate‐induced toxicity reduced chlorate and nitrate more rapidly than did resistant plants. In experiments testing the potential of this assay, wheat and barley (Hordeum vulgare L.) cultivars previously reported to have low NRA were less susceptible to chlorate‐induced toxicity than were cultivars reported to have high NRA. The assay was used to screen 15 soft red winter wheat cultivars for differences in sensitivity to chlorate‐induced toxicity. Variable toxic reactions were observed both among and within the cultivars. To determine whether the within‐cultivar variation was environmental or genetic, single plant selections for contrasting chlorate response were made, and bulked progeny were rescreened. In eight of 15 cultivars, the contrasting selections were different for chlorate‐induced toxic response, indicating heterogeneity for this trait within these eight cultivars. These chlorate‐selected lines may also be near‐isogenic lines for NRA. Seedling screening of wheat for chlorate response may be useful for identification of high NRA breeding lines.     

种子钼对冬小麦硝酸还原酶活性、干物质重及产量的影响

在酸性黄棕壤上 ,研究了种子钼对冬小麦幼苗NRA(硝酸还原酶活性 )、拔节期地上部干物质重和小麦子粒产量的影响。结果表明 ,不管施钼与否 ,苗期NRA与种子钼含量呈极显著正相关。拔节期地上部干物质重与种子钼含量呈极显著正相关 ,但施钼以后无明显相关性。小麦子粒产量与种子钼含量无显著相关性。种子钼处理 (种子钼加土壤有效钼 )对大多数品种的幼苗NRA、拔节期干物质重和子粒产量 ,均比施钼处理极显著降低。这些表明 ,种子钼对植物体的生长有一定作用 ,但不足以保证冬小麦正常生长发育并获得高产。因此 ,在施钼是在缺钼土壤上矫正缺钼、促进冬小麦生长发育、获得高产的必要措施之一。     

Free amino acids of tronchuda cabbage (Brassica oleracea L. Var. costata DC): influence of leaf position (internal or external) and collection time

The free amino acid profile of 18 samples of tronchuda cabbage ( Brassica oleracea L. var. costata DC) leaves, harvested at three different months, was determined by HPLC/UV-vis. The tronchuda cabbage leaves total free amino acid content varied from 3.3 to 14.4 g/kg fresh weight. Generally, arginine was the major compound, followed by proline, threonine, glutamine, cysteine, and glutamic acid. This study indicates that free amino acids are not similarly distributed: in external leaves, proline and arginine were the major free amino acids, while in internal ones, arginine was the main free amino acid, followed by threonine, glutamine, and cysteine. Significant differences were observed for valine, proline, arginine, leucine, cysteine, lysine, histidine, and tyrosine contents. The levels of some free amino acids were significantly affected by the collection period. In external leaves, this occurred with glutamic acid, serine, valine, leucine, cysteine, and ornithine contents, while in internal leaves, it occurred with aspartic acid, arginine, and total contents.     

高铝低磷胁迫对胡枝子生长及矿质元素吸收的影响

限制酸性土壤作物生长的最重要、最普遍的因子是Al3+ 的毒害和 P 的缺乏.本文用溶液培养试验研究两种不同生态型的二色胡枝子在高Al低P胁迫下的矿质营养元素积累情况.试验表明,江西胡枝子比河北胡枝子更耐低 P 低 pH 的生长环境,但两者间耐Al性无显著差异;100 μm/L Al 处理显著地抑制了两种胡枝子对 Ca 的吸收,降低了根系 Mg 的积累量,对植株的 K、P、Fe、Zn、Cu 含量没有显著影响;低 P 处理没有显著降低两种胡枝子对 Ca、K、Fe、Zn、Cu 和江西胡枝子对 Mg 的吸收,但是低 P 处理显著降低了河北胡枝子对 Mg 的吸收和转运.二色胡枝子植株吸收的 Al 主要积累在根部,地上部分Al含量仅是根系的1% 左右.