大豆磷酸烯醇式丙酮酸磷酸酯酶(PEPP)研究:Ⅰ. 对非生物胁迫的反应

对缺磷、铝毒、盐、干旱、Fe、Mn、Cu、Zn胁迫下大豆根系和叶片磷酸烯醇式丙酮酸磷酸酯酶(PEPP)活性进行了测定，结果表明：(1)长期缺磷和铝毒胁迫可显著提高大豆根系的PEPP活性，并表现出加成效应；(2)长期铝毒、缺磷和铝毒耦合胁迫也显著提高大豆敏感品种BL2叶片的PEPP活性；(3)盐胁迫、干旱以及长期Fe、Mn、Cu、Zn过量都显著提高大豆根系的PEPP活性，Fe、Cu、Zn缺乏则对根系和叶片的PEPP活性影响不大，长期缺Mn显著降低大豆根系及叶片的PEPP活性。     

磷对铝胁迫下荞麦元素吸收与运输的影响

以不同耐铝基因型江西养麦(耐性)和内蒙荞麦(敏感)为材料,采用土培法研究磷对铝胁迫下荞麦生长和Al,P等元素吸收、运输的影响.结果表明,铝胁迫下0.2 g/kg的磷能有效缓解铝毒对荞麦根长的抑制.培养30d后,0.4 g/kg磷处理能显著降低铝在荞麦根系和地上部的积累.铝胁迫下加磷可影响养麦体内Ca,Mg,Mn,Zn,Fe的吸收,0.4 g/kg铝配施0.4 g/kg磷处理对荞麦根系Ca,Mg吸收最有利,内蒙荞麦根系Mg的含量比不加磷组提高了76.8%,但显著阻碍了铝胁迫下荞麦体内Ca,Fe的向上运输.铝胁迫下配施磷促进荞麦根系对Zn,Fe吸收,有利于Zn向地上部转运.施磷能有效缓解铝毒对荞麦生长的抑制,降低根系和地上部铝含量,有利于Ca,Mg,Mn,Zn,Fe的吸收和Mg,Zn的运输.     

外源一氧化氮介导铜胁迫下番茄幼苗中铁、锌、锰的累积及亚细胞分布

采用营养液培养方法,以改良毛粉802F1番茄为材料, 研究外源一氧化氮（NO,SNP为供体）对铜（Cu）胁迫下番茄幼苗铁（Fe）、 锌（Zn）、 锰（Mn）吸收分配的影响。结果显示, 50 mol/ L的 Cu2+ 胁迫下,番茄幼苗的生物量和株高显著降低了33.7% 和23.1%,外施100 mol/L SNP可显著缓解这种抑制作用, 提高Cu 胁迫下番茄幼苗根系、 茎中Fe、 Mn含量及叶柄、 叶片中Fe、 Zn含量,降低茎中Zn含量及叶柄、 叶片中Mn含量; 根系、 茎、 叶柄、 叶片Fe、 Zn及根系和茎中Mn的累积相应增加; 根系吸收的Fe、 Zn、 Mn向地上部的转运降低。Cu 胁迫下, 外源NO可显著提高番茄液泡、 细胞器的Fe、 Zn 含量, 降低根系和叶片细胞壁Fe、 Zn、 Mn含量。在作为转运组织的茎和叶柄中,Mn主要分布在细胞壁上,而在叶柄和叶片液泡、 细胞器中也有增加。表明外源NO可以调控番茄幼苗各部位及亚细胞中Fe、 Zn、 Mn的合理分布,维持胞质离子稳态和矿质营养元素平衡,缓解铜胁迫,保证番茄幼苗正常的生理代谢。     

硒对镉胁迫下寒地水稻Cd、Zn、Fe、Cu、Mn含量的影响

研究了镉胁迫下施硒后水稻各器官Cd、Zn、Fe、Cu、Mn含量的变化,并探讨了施硒对缓解镉胁迫下水稻养分吸收的可行性。采用人工模拟镉胁迫的盆栽试验方法,研究不同镉浓度(0,2,4,8mg/kg土壤)下,施硒(0,0.07,0.14mg/kg土壤)对水稻不同器官Cd、Zn、Fe、Cu、Mn含量的影响。结果表明:(1)随着土壤镉浓度的增加,水稻各器官镉含量均增加,不同器官镉含量表现为根系茎鞘叶片精米。(2)相同镉浓度下,随着硒浓度的增加,各器官中镉含量下降,Se2(0.14 mg/kg)优于Se1(0.07 mg/kg)处理。Cd1(2mg/kg)浓度时,Se2处理精米镉含量比Se0降低31.5%(P0.01)。(3)镉胁迫下,施硒对水稻各器官中Zn、Fe、Cu、Mn含量影响不同。相同镉浓度下,随着硒浓度的增加,叶片Zn含量下降,Fe含量增加;茎鞘Zn、Fe含量下降,而Cu含量增加;根系Zn、Cu含量下降,而Fe、Mn含量增加;精米Zn、Mn、Cu、Fe含量增加。其中Cd2(4mg/kg)浓度时,与Se0处理相比,Se2处理茎鞘Zn含量降低了36.2%;叶片和根系Fe含量增加了15.4%和11.4%;精米Zn、Mn、Cu、Fe显著含量增加,分别增加了43.3%,15.8%,52.6%,20.5%(P0.01)。施硒能显著降低镉胁迫下寒地水稻镉含量,Cd1浓度下,施硒后精米镉含量下降幅度最大;镉胁迫下施硒影响水稻对Zn、Fe、Cu、Mn的吸收,尤其Cd2浓度下,施硒对精米Zn、Mn、Cu、Fe含量影响较大,Se2处理效果最佳。     

外源NO对铜胁迫下番茄光合、生物发光特性及矿质元素吸收的影响

采用营养液培养,研究了外源一氧化氮（NO）供体硝普钠(Sodium nitroprusside, SNP)对50 μmol/L铜（Cu）胁迫下番茄叶片叶绿素含量、光合特性、生物发光强度和矿质营养元素的影响。结果表明,在Cu胁迫下,外施100 μmol/L SNP显著提高番茄叶片叶绿素a、叶绿素b、叶绿素a+b含量、叶绿素a/b比值、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和叶片中Cu、Ca、Fe、Zn、Mn以及根系中Cu、K、Fe、Zn的含量; 显著降低叶片超微弱发光强度、荧光强度、磷光强度、胞间CO2浓度(Ci)和根系中Ca的含量。然而,SNP对Cu胁迫下的缓解效应可被NO的清除剂血红蛋白所抑制。在Cu处理液中加入100 μmol/L NO-x（NO的分解产物）或100 μmol/L亚铁氰化钠（SNP的相似物或分解产物）,与Cu胁迫处理差异不显著。表明外源NO可以通过改善Cu胁迫下番茄叶片光合特性,降低超微弱发光、荧光、磷光强度,维持矿质营养元素平衡,缓解Cu胁迫对番茄的抑制作用。     

长期施肥对关中塿土微量元素有效性的影响

以28年的长期肥料定位试验为基础,探讨了对照不施肥(CK),单施有机肥(M2),单施氮、磷肥(N2P2),有机肥+氮、磷肥配合施用(M2N1P1和M2N2P2)5个施肥处理对关中塿土微量元素Fe,Mn,Zn,Cu有效性的影响。结果表明,长期施肥对耕层土壤有效Fe,Mn,Cu,Zn含量影响较大,在耕层土壤(0—20 cm)中,长期不施肥土壤有效Fe,Mn,Cu,Zn含量均处于亏缺边缘;长期单施氮、磷化肥处理的土壤Fe,Cu,Zn也接近亏缺边缘;而长期单施有机肥、有机肥与氮、磷化肥配合处理,土壤有效Fe,Mn,Cu,Zn含量丰富。与CK相比,M2、M2N1P1、M2N2P2均可显著增加0—10 cm土层中有效Fe、Mn、Cu和Zn含量,10 cm以下土层中,土壤有效Fe、Mn、Cu、Zn在一定程度上也有增加趋势;N2P2也可增加0—10 cm土层中土壤有效Fe和Mn含量(有效Mn达到显著水平),有效Cu含量降低,对有效Zn含量没有影响,而10 cm以下土层中土壤有效Fe,Mn,Cu,Zn与CK无明显差异。因此,塿土在不施用有机肥的情况下,应施用微肥以保证作物需求;即使施用有机肥,也应适当补充铁肥和锰肥。有机肥和氮、磷化肥配合施用的土壤微量元素养分状况较好。     

长期施肥对关中土微量元素有效性的影响

以28年的长期肥料定位试验为基础,探讨了对照不施肥（CK）,单施有机肥（M2）,单施氮、磷肥（N2P2）,有机肥+氮、磷肥配合施用（M2N1P1和M2N2P2）5个施肥处理对关中土微量元素Fe,Mn,Zn,Cu有效性的影响。结果表明,长期施肥对耕层土壤有效Fe,Mn,Cu,Zn含量影响较大,在耕层土壤（0—20cm）中,长期不施肥土壤有效Fe,Mn,Cu,Zn含量均处于亏缺边缘; 长期单施氮、磷化肥处理的土壤Fe,Cu,Zn也接近亏缺边缘; 而长期单施有机肥、有机肥与氮、磷化肥配合处理,土壤有效Fe,Mn,Cu,Zn含量丰富。与CK相比,M2、M2N1P1、M2N2P2均可显著增加0—10 cm土层中有效Fe、Mn、Cu和Zn含量, 10 cm以下土层中,土壤有效Fe、Mn、Cu、Zn在一定程度上也有增加趋势; N2P2也可增加0—10 cm土层中土壤有效Fe和Mn含量（有效Mn达到显著水平）,有效Cu含量降低,对有效Zn含量没有影响,而10 cm以下土层中土壤有效Fe,Mn,Cu,Zn与CK无明显差异。因此,土在不施用有机肥的情况下,应施用微肥以保证作物需求; 即使施用有机肥,也应适当补充铁肥和锰肥。有机肥和氮、磷化肥配合施用的土壤微量元素养分状况较好。     

激光剥蚀–电感耦合等离子体质谱分析缺锌胁迫玉米根尖微量元素空间分布

【目的】激光剥蚀?电感耦合等离子体质谱 (laser ablation inductively coupled plasma mass spectrometry,LA-ICP-MS) 法是一种利用聚焦激光扫描激发固体样品,并经电感耦合等离子体质谱离子化,以分析样品元素含量及分布的新兴技术。本文利用LA-ICP-MS技术研究缺锌 (Zn) 胁迫下玉米根尖铁 (Fe)、锰 (Mn)、铜 (Cu)、Zn元素的分布定位,以期从组织水平揭示作物中Zn的转运富集规律及缺Zn对微量金属元素吸收转运的影响。【方法】以玉米‘郑单958’为试材,用不同加锌浓度营养液进行培养,获得根系样品烘干后磨碎、混匀、压片,取适量混匀的根系样品消煮,利用液体进样系统ICP-MS检测得到样品中实际元素含量,并与样品压片LA-ICP-MS检测信号值间进行线性回归分析,标准曲线相关性良好 (R2 = 0.9995),从而获得可适用于LA-ICP-MS定量分析的自制根系标准样品。将此标准样品与待测根尖样品放入LA样品池中,13C作为内标元素,进行缺锌胁迫下玉米根尖中锌元素分布特征的定量成像研究。【结果】缺锌胁迫下玉米根系锌元素含量显著降低,仅为正常植株的27.78%;缺锌根系中Mn和Cu含量升高。LA-ICP-MS系统定量成像显示,玉米根尖顶端Zn含量较高,由表皮向内锌含量逐渐增加;缺Zn处理根系Zn含量降低,根尖顶端Zn分布明显减少。利用LA-ICP-MS检测信号强度值对Fe、Mn、Cu元素进行定性分布,成像显示在正常根系中Fe、Mn、Cu元素在根尖前端信号强度较高,由表向内逐渐增加;缺锌处理下,根系中Fe、Mn、Cu信号强度均有不同程度增加。【结论】正常施锌玉米根尖中锌、铁、锰、铜分布呈现由表皮向中柱增加的趋势;缺锌胁迫下根系锌含量显著降低,铁、锰、铜均有不同程度积累。     

三江平原白浆土中Fe、Mn、Cu和Zn生物有效性的研究

在三江平原上,测定 42 个小区中玉米、大豆、小麦籽实 Fe、Mn、Cu 和 Zn 含量和土壤中各形态 Fe、Mn、Cu 和Zn含量.通过相关分析和通径分析,探讨了土壤中各形态Fe、Mn、Cu 和 Zn 的生物有效性,旨在为该地区合理施用微量元素提供科学依据.试验结果表明,玉米、大豆和小麦籽实含 Fe、Mn、Cu 和 Zn 量与土壤中有效态和交换态 Fe、Mn、Cu和Zn含量呈显著或极显著正相关.有机态 Fe、Mn、Cu 和 Zn含量与玉米、大豆和小麦籽实Fe、Mn、Cu 和 Zn含量也有很好的相关关系.交换态对有效态 Fe、Mn、Cu 和 Zn 影响最大,其次是有机质结合态.铁锰氧化物结合态 Fe、Cu 对有效态 Fe、Cu 及碳酸盐结合态 Mn、Zn 对有效态 Mn、Zn 具有一定正效应.而残留态 Fe、Cu 对有效态 Fe、Cu 和铁锰氧化物结合态 Mn 对有效态 Mn 产生负效应.     

重金属胁迫对水稻不同品种超氧化物歧化酶的影响

用不同浓度的Cd2 + 、Cu2 + 和Hg2 + 处理花期的扬稻 6号 (籼稻 )、武育粳 8号 (粳稻 )和协优 81 8(杂交稻 ) ,测定各器官SOD活性 ,并进行SOD同功酶的电泳分析。结果表明 ,较高浓度重金属显著抑制各品种根系SOD活性 ,也抑制叶片SOD活性 ,但抑制程度因重金属种类和品种类型而异。各浓度均抑制武育粳穗SOD活性 ,但诱导扬稻 6号穗SOD活性增高。协优 81 8穗SOD活性受Cd2 + 抑制 ,但却受高浓度Cu2 + 和Hg2 + 诱导。≥ 2 0ppmCd2 + 、Cu2 + 和Hg2 + 均抑制水稻根系SOD同功酶表达 ,但诱导扬稻 6号和协优 81 8穗SOD同功酶表达。Mn SOD和Cu Zn SOD同功酶对重金属胁迫的敏感性不同 ,重金属对水稻根系Mn SOD的抑制程度明显高于Cu Zn SOD。     

Aluminum toxicity in plants grown in solution culture

Abstract

Earlirose rice (Oryza sativa L. ) and Hawkeye soybeans (Glycine max L.) were grown in solution culture with A1₂(SO₄)₃ in concentrations of 0, 10^‐6, 10^‐5, 10^‐4, 10^‐3 M. Only at 10^‐4 (slightly) and at 10^‐3 M were there yield depressions due to Al. The threshold concentration of Al for toxicity was about 20 μg/g in rice shoots and about 30 μg/g in soybean leaves. The solution level necessary for these concentrations was 8 μg Al/ml. Plant concentrations which caused severe toxicity were 70 μg Al/g plant with 81 μg Al/ml solution. Most Al remained in roots, but leaves contained more than did stems of soybeans. The high Al decreased Fe, Cu, and Mn concentrations in shoots of rice and decreased Fe, Cu, and Zn in roots of rice. The high Al resulted in decreased Fe and Zn in leaves of soybeans. No Fe deficiency symptoms were present due to the high Al.     

Effects of excess aluminum on mineral uptake in mycorrhizal sorghum

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.     

Effects of Nickel on Growth and Composition of Metal Micronutrients in Barley Plants Grown in Nutrient Solution

Abstract

A hydroponic experiment was conducted in a phytotron at pH 5.5 to study the effects of nickel (Ni) on the growth and composition of metal micronutrients, such as copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), of barley (Hordeum vulgare L. cv. Minorimugi). Four Ni treatments were conducted (0, 1.0, 10, and 100 μM) for 14 d. Plants grown in 100 μM Ni showed typical visual symptoms of Ni toxicity such as chlorosis, necrosis of leaves, and browning of the root system, while other plants were free from any symptoms. Dry weights were the highest in plants grown in 1.0 μM Ni, with a corresponding increase in the chlorophyll index of the plants, suggesting that 1.0～10 μM Ni needs to be added to the nutrient solution for optimum growth of barley plants. The increase of Ni in the nutrient solutions increased the concentrations of Cu and Fe in roots, while a decrease was observed in shoots. The concentrations of Mn and Zn in shoots and roots of plants decreased with increasing Ni supply in the nutrient solution. Shoot concentrations of Cu, Fe, Mn, and Zn in plants grown at 100 μ M Ni were below the critical levels for deficiency. Plants grown at 1.0 μ M Ni accumulated higher amounts of Cu, Fe, Mn and Zn, indicating that nutrient accumulation in plants was more influenced by dry weights than by nutrient concentrations. The translocation of Cu and Fe from roots to shoots was repressed, while that of Mn and Zn was not repressed with increasing Ni concentration in the nutrient solution.     

苹果MxNas1基因正反义表达载体构建及转化烟草的研究

为研究笔者前期克隆的MxNas1基因功能,构建了苹果属植物小金海棠MxNas1基因正义和反义两种表达载体,并用农杆菌介导的叶盘转化法转化了烟草.对转基因烟草分别进行0和1μmol/L Fe处理14d后,转正义载体烟草在缺Fe情况下叶片没有黄化,表现出较强的抗缺Fe能力;转反义载体植株比对照烟草幼叶提前出现黄化现象,表现...     

Aluminum toxicity in tomato. Part 1. growth and mineral nutrition

Aluminum (Al) toxicity was studied in two tomato cultivars (Lycopersicon esculentum Mill. ‘Mountain Pride’ and Floramerica') grown in diluted nutrient solution (pH 4.0) at 0, 10, 25, and 50 μM Al levels. In the presence of 25 and 50 μM Al, significant reduction was found in leaf area, dry weight, stem length, and longest root length of both cultivars. Growth of ‘Floramerica’ was less sensitive to Al toxicity than growth of ‘Mountain Pride’. Elemental composition of the nutrient solutions were compared immediately after the first Al addition and four days later. The uptake of micronutrients copper (Cu), manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B), and iron (Fe) from the nutrient solution was reduced in both cultivars with increasing Al levels. Nutrient solution Al gradually decreased in time for every treatment; less in cultures of ‘Floramerica’ than in ‘Mountain Pride’. Aluminum treatments decreased the calcium (Ca), potassium (K), magnesium (Mg), Mn, Fe, and Zn content in the roots, stems, and leaves. Aluminum treatment promoted the accumulation of P, Mo, and Cu in the roots, and inhibited the transport of these nutrients into stems and leaves. At 25 and 50 μM levels of Al, lower Al content was found in the roots of cv. “Floramerica’ than in the roots of cv. ‘Mountain Pride’.     

Effect of iron plaque on roots of rice on growth of plants in excess zinc and accumulation of phosphorus in plants in excess copper or nickel

Iron (Fe) plaque on roots of rice was found to lessen the toxic effects of zinc (Zn). With excess Zn, plants with Fe plaque had significantly greater dry mass of roots and foliage than plants without plaque. In the excess of Zn, plants with Fe plaque had higher concentrations of Fe but lower Zn than plants without plaque, although the differences were not significant. In the excess of copper (Cu) or nickel (Ni), plants with Fe plaque had significantly lower concentration of phosphorus (P) in leaves than plants without plaque. It is suggested that the low concentration of P in leaves of plants with plaque will increase the concentration of “active iron”; inside leaves, and therefore, increase their tolerance against heavy metal toxicity.     

Effects of Manganese on Uptake and Translocation of Nutrients in a Hyperaccumulator

The effects of manganese (Mn) on the growth and Mn-induced changes in nutrients uptake and translocation in Mn hyperaccumulator Phytolacca acinosa was investigated in this study. Results showed that high Mn (5000 μ M) in culture solution lead to typical Mn toxicity symptoms in leaves of P. acinosa and decrease of dry matter accumulation in shoots whereas there are no obvious toxicity symptoms and significant decrease of dry weight in roots. Manganese accumulation in roots, stems, and leaves increased with the increment of Mn concentration at the medium level. Calcium (Ca), magnesium (Mg), and iron (Fe) concentration in organs of P. acinosa decreased as the Mn concentration in the nutrient solution increased, but the Ca and Mg concentrations were still at a normal level and the Fe concentration at a sufficient level when compared with the normal plants. The Zn concentration affected by higher Mn level occurred only in roots of P. acinosa and the P concentration affected only in stems, whereas there were no significant influences of excess Mn on the potassium (K) and copper (Cu) concentration in organs of P. acinosa.     

不同氮素形态对干旱胁迫杉木幼苗养分吸收及分配的影响

【目的】干旱胁迫是限制植物生长的重要非生物因素之一,而适宜的氮素营养可以提高植物的抗旱性。本文探讨了供应不同形态氮源对干旱条件下杉木[Cunninghamia lanceolata (Lamb.) Hook]幼苗养分吸收及分配的影响。【方法】采用水培试验,供试杉木材料为2个无性系幼苗(7–14号和8–8号),在营养液中添加10%(w/v)PEG-6000进行干旱胁迫。营养液中的氮源处理包括硝态氮、铵态氮、硝铵混合氮,氮素浓度均为4.571mmol/L,每个品种均设6个处理。培养20天后,测定了杉木幼苗根、茎、叶的养分含量及生物量。【结果】与正常水分供应相比较,干旱胁迫条件下供应铵态氮可促进叶片N、K以及茎叶P、K的吸收,供应混合氮可促进根部K的吸收;供应铵态氮可促进根、茎对Ca的吸收,对叶片Ca无明显作用。干旱胁迫对根部Fe、Mn、Cu、Zn吸收量影响显著,氮素供应不同程度地降低了干旱胁迫下各器官Mg、Fe、Mn和Cu吸收量,表现为抑制吸收,但添加铵态氮比硝态氮的降低幅度小。3个氮源处理均降低了干旱条件下根部Zn吸收量,但没有降低甚至增加了茎、叶中Zn的吸收量,说明氮营养可调节Zn在各器官间的分配,缓解干旱导致的缺锌现象。不同器官之间各养分吸收量差异显著,3个氮源处理中,N和P吸收量表现为叶>根>茎,K和Ca为叶>茎>根,Fe、Cu为根>叶>茎,Mg、Mn和Zn在各器官之间的分配规律不一。铵态氮吸收量均表现为叶>根>茎,且各器官铵态氮吸收量显著高于硝态氮,说明杉木具有明显的喜铵特性。【结论】在干旱胁迫下,氮素供应形态显著影响杉木幼苗对养分的吸收及在各器官中的分配,作用效果因家系品种和元素种类而异。总体来讲,铵态氮提高干旱胁迫下杉木幼苗养分吸收的效果好于硝态氮,杉木可以认为是喜铵植物。     

Interactive effects of aluminum and chromium stresses on the uptake of nutrients and the metals in barley

Aluminum (Al) and chromium (Cr) stresses often occur simultaneously in agricultural soils, and pose a great damage to crop growth, yield formation and product safety. In the current study, the influence of combined Al and Cr stresses on plant biomass, metal and nutrient contents was determined in comparison with that of Al or Cr stress alone. A hydroponic experiment was conducted to investigate the effect of pH, Al and Cr in the medium solution on the uptake of mineral elements as well as Al and Cr in the two barley genotypes differing in Al tolerance. Aluminum sensitive genotype Shang 70-119 had significantly higher Cr and Al contents in plants than Al-tolerant genotype Gebeina. Barley roots had much higher Al and Cr contents than above-ground plant parts. Chromium contents were much higher in the solution with pH 4.0 than in that with pH 6.5. Aluminum stress reduced phosphorus (P), calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) contents in roots and restrained potassium (K) and iron (Fe) from being translocated into shoots and leaves. Chromium stress resulted in reduced P, K, Mg, S, Fe, Zn and Mn contents in roots at pH 6.5 and P, K, Ca, Mg, S, Zn and Mn contents at pH 4.0. Translocation of all nutrients from roots to upper parts of plants was inhibited except Ca in pH 6.5 with Cr addition. Lower contents of all nutrients were observed at pH 4.0 as compared to pH 6.5. Combined stress of Cr and Al, on the whole, caused further reduction in mineral content in all plant parts of the two barley genotypes as compared to Al or Cr stress alone. Moreover, the reduction was more pronounced in Al sensitive genotype Shang 70-119.     

缺磷对不同作物根系形态及体内养分含量浓度的影响

采用营养液培养方法,以水稻、 小麦、 玉米和大豆为试验材料,研究了短期缺磷（2周）诱导根表沉积铁氧化物是否为水稻特有的性质,以及缺磷对不同作物根系形态及其吸收钾、 钙、 铁、 锰、 铜、 锌营养元素的影响。结果表明,供磷和缺磷处理并没有影响小麦、 玉米和大豆3种作物根系的颜色,而缺磷处理水稻根表沉积了铁氧化物而呈红（黄）棕色,且铁氧化物不均匀地富集在根细胞壁的孔隙中; 缺磷促进了水稻,小麦,玉米和大豆根系的生长,分别比供磷处理伸长了11%、 11%、 20%和11%（P0.05）。此外,缺磷胁迫下水稻根表铁氧化物增强了钙、 铁、 锰、 铜和锌在根表的富集而成为其进入根系的缓冲层。缺磷处理水稻根中铁浓度明显高于供磷处理（P0.05）,而地上部铁的浓度仅为磷营养正常水稻植株的18%,这说明缺磷诱导的铁氧化物促进了根系对铁的吸收但抑制了铁由根系向地上部的转运。短期缺磷对其他养分在水稻根中和地上部的浓度没有明显影响。对于其他 3 种作物,短期缺磷没有明显影响钾、 钙、 铁、 锰、 铜和锌在其根表富集及在植物体内的浓度。因此,在供试的4 种作物中,由于磷胁迫诱导根表形成铁氧化物是水稻特有的性质,铁氧化物的沉积可促进铁的吸收但抑制了铁向地上部的转运,而短期缺磷并没有影响其他3种作物对钾、 钙、 铁、 锰、 铜和锌养分的吸收和转运。