铝诱导有机酸分泌的耐铝机理研究进展

铝毒是限制酸性土壤中植物生长和作物生产以及森林退化的主要因子。为了能在有铝毒害的环境下生长,植物进化出一系列的耐铝毒机制。铝诱导下有机酸分泌解铝毒是植物耐铝研究的一个热门领域。本研究综述了植物根系分泌有机酸的种类以及有机酸解铝毒的机理,并从有机酸通道蛋白基因鉴定、克隆以及功能分析等方面进行综述;同时指出植物耐铝毒是多基因控制的复杂特性,因此,从耐铝基因的表达调控方面进行深入研究,将有效揭示植物抗铝的机制。     

52份豌豆种质萌发期耐铝毒性的综合评价与筛选

随着土壤酸化的日益加重,铝毒成为影响作物种子萌发质量以及产量的重要胁迫因子之一。本研究采用单项耐铝毒系数(AC值)、综合耐铝毒系数(CAC值)、平均隶属函数值(ASF值)、耐性综合评价值(A值)等指标及相关分析、主成分分析、聚类分析和逐步回归分析等方法,综合评价豌豆种质萌发期铝毒耐性,建立综合筛选评价体系,并筛选萌发期耐铝毒豌豆种质。利用筛选出的适宜浓度40 mg L–1Al3+处理52份豌豆品种(系)种子,结果显示,萌发期8个相关性状在处理组及对照组品种间均存在显著差异,遗传多样性指数分别介于1.43～2.03和1.51～2.06之间。基于AC值聚类分析, 52份豌豆种质可被分为3个耐性级别,其中,第I级含2份,为耐铝毒品种(系);第II级含19份,为敏感品种(系);第III级含31份,为铝毒极敏感性品种(系)。利用豌豆种子发芽率、发芽势、发芽指数、芽长、根长、芽干重、根干重7项指标,结合最优回归方程可初步鉴定豌豆萌发期耐铝毒特性。通过综合评价和聚类分析,筛选出萌发期铝毒耐性极强的种质C175和C145,可作为豌豆铝毒耐性育种和耐性机制研究的重要资源。     

利用体细胞无性系变异培育籼稻铝毒耐性品系

为了提高水稻对铝毒的耐性，本试验使用了离体培养诱导的体细胞无性系变异。通过离体培养筛选胚发生的愈伤组织而培育成了耐性植株。用成熟种子胚诱导出愈伤组织，再将其愈伤组织培养在添加有不同浓度Al2（SO4）318H2O的培养基中。随着铝（Al）浓度的增高，种子萌发、愈伤组织诱导、小苗再生和愈伤组织的健康状况都降低了。     

甘蓝型油菜种子萌发期耐铝毒特性综合评价及其种质筛选

种子萌发是油菜植株形态建成的重要阶段,铝毒是酸性土壤中影响其种子萌发的主要因素之一,因此筛选出种子萌发过程中耐铝毒种质对油菜生产及研究具有重要意义。本研究利用5份甘蓝型油菜品种(系)筛选出油菜萌发期耐铝毒种质资源处理的适宜胁迫浓度为90μg mL~(-1)。并以该浓度处理148份甘蓝型油菜品种(系)种子,于萌发期测定其发芽势、发芽率、鲜重、干重、根长和芽长等指标,通过铝毒胁迫耐性综合评价值(A值)、平均隶属函数值(ASF值)、对铝毒加权耐性系数(WAC值)、相关性、频数、主成分、灰色关联度、聚类和逐步回归分析等鉴定萌发期耐铝性,建立萌发期对铝毒耐性综合评价模型并筛选出适宜的评价鉴定指标。结果表明, 148份甘蓝型油菜的萌发期各指标在品种(系)间存在显著差异;筛选出萌发期耐铝毒甘蓝型油菜品种(系) 01188、WH-20、A109、甲预31棚等。根据灰色关联度及回归分析结果认为,在油菜萌发期测定其根长、芽长、鲜重、发芽率和发芽势,通过回归方程估算其A值,可以初步判断甘蓝型油菜种质的耐铝毒特性。     

植物铝毒及其耐铝机制研究进展

铝毒是酸性土壤上作物生产的主要限制因子,目前有关作物铝毒害及耐铝的机理尚不十分清楚,限制了相关育种和栽培工作的开展。近几年来,世界各国针对作物的铝毒害及其耐铝机制进行了大量的研究,并取得了较大进展。本文综述了目前有关铝对植物的毒害及其耐铝机理的研究成果,并简要讨论了今后的研究方向。     

基于AEZ模型的我国水稻产量潜力的农作制区划分析

本文根据联合国粮农组织(FAO)和国际应用系统分析研究所(IIASA)基于中国1961~1997年的统计资料(经多方校正)共同开发的AEZ模型,运用G IS平台计算了中国41个农作制亚区的水稻生产潜力,并指出了单产最高潜力分布区域。研究结果表明:我国水稻的最高产量潜力大约将是目前产量的2倍。这对我国水稻高产育种及栽培具有重要参考意义。     

利用重组自交系群体检测水稻耐铝毒数量性状基因座

利用Kinmaze / DV85 81个重组自交家系(RIL)作图群体,采用苗期单营养液水培鉴定方法,以相对根伸长量（RRE）作为耐铝毒性状的表型值,分析亲本和重组自交系群体对铝毒的耐性表现。利用Windows QTL Cartographer 1.13a软件共检测到5个耐铝毒QTLs,分别位于第1、5、8、9和11染色体上,各个QTL的贡献率在8.64%～18.60%之间,其     

节水农作制度形成机制的研究

从自然生态、经济、社会三个方面探讨节水农作制度形成的影响因素,将所涵盖的因素又分别细分为几类,从理化机制及国内外实践经验出发,科学分析了各种因素对节水农作制度形成与发展的制约形式,建立中国旱作地区节水农作制度形成机制的基本理论框架,并提出节水农作制度综合效益评价的构想.     

水稻作物对重金属镉的积累、耐性机理以及栽培调控措施进展

为了更加深入研究水稻作物对土壤中镉的积累与毒害耐性机理、了解栽培调控措施对稻米安全生产的意义,本文归纳了水稻作物对镉的转运和积累,分析了水稻镉积累差异及其特征;总结了水稻作物耐镉胁迫的机制,从抗氧化系统,限制吸收和运输,螯合作用等方面分析了水稻对镉胁迫的耐性机制;从肥料、水分等方面分析了栽培措施对水稻镉吸收和积累的调控效应。提出了应加强污染预防品种的选育和栽培调控措施研究等工作的意见和建议。     

基于AEZ模型的我国农区主要作物单产潜力分析

根据联合国粮农组织（FAO）和国际应用系统分析研究所（ⅡASA）基于中国1961年以来的统计资料共同开发的AEZ模型,运用GIS平台计算了中国41个农作制亚区6大主要作物（水稻、小麦、玉米、马铃薯、油菜、大豆）的单产潜力。指出以上作物单产最高潜力分布为：水稻在江淮江汉平原,小麦在秦巴山区,玉米在黄淮平原南阳盆地,马铃薯在秦巴山区,油菜在秦巴山区,大豆在鲁西平原鲁中丘陵。研究结果表明：我国以上主要作物的最高单产潜力是目前全国平均单产的1.2～2.9倍。这对指导我国农作物高产育种及栽培具有重要参考意义。     

Inheritance of root regrowth as an indicator of apparent aluminum tolerance in triticale

Aluminum (Al) toxicity is a predominant growth-limiting factor in acid soils. Better understanding of the genetic mechanisms by which plants tolerate toxic Al expedites the development of tolerant plant genotypes. The genetic behavior of apparent Al tolerance in two triticale crosses as measured by root regrowth of seedlings at a level of 10 μg · ^g−1 Al stress in nutrient solutions was analyzed by following a bi-parental (BIP) mating design. The validity of the additive-dominance genetic model was tested with relevant gene effects estimated. The continuous variation of regrown root length showed that apparent Al tolerance was a metrical character in nature. Both the additive and dominance effects were responsible while the additive effects played a major role in the expression of Al tolerance. Non-allelic interaction (or epistasis) was indicated from the inadequacy of the model and different types of epistatic gene effects were detected in the two crosses. These results suggest that Al tolerance was of polygenic system rather than simply inherited. One to three pairs of genes were involved in apparent Al tolerance for the parental difference. The moderately high value of estimates of heritability together with the estimates of genetic advance (GA) could be used in planning a selective breeding program aimed at greater Al tolerance. This revised version was published online in July 2006 with corrections to the Cover Date.     

Validation of quantitative trait loci for aluminum tolerance in Chinese wheat landrace FSW

Aluminum (Al) toxicity is one of the major constraints for wheat production in acidic soils worldwide and use of Al-tolerant cultivars is one of the most effective approaches to reduce Al damage in the acidic soils. A Chinese landrace, FSW, shows a high level of tolerance to Al toxicity and a mapping population of recombinant inbred lines (RILs) was developed from a cross between FSW and Al-sensitive US spring wheat cultivar Wheaton to validate the quantitative trait loci (QTL) previously identified in FSW. The mapping population was evaluated for net root growth (NRG) during Al stress in a nutrient solution culture and hematoxylin staining score (HSS) of root tips after Al stress. After 132 simple sequence repeat (SSR) markers from three chromosomes that were previously reported to have the QTLs were analyzed in the population, two QTLs for Al tolerance from FSW were confirmed. The major QTL on chromosome 4DL co-segregated with the Al-activated malate transporter gene (ALMT1), however, sequence analysis of the promoter region (Ups4) of ALMT1 gene indicated that FSW contained a marker allele that is different from the one that was reported to condition Al tolerance in the Brazilian source. Another QTL on chromosome 3BL showed a minor effect on Al tolerance in the population. The two QTLs accounted for about 74.9 % of the phenotypic variation for HSS and 72.1 % for NRG and demonstrated an epistatic effect for both HSS and NRG. SSR markers closely linked to the QTLs have potential to be used for marker-assisted selection (MAS) to improve Al tolerance in wheat breeding programs.     

A cytological study on aluminium-treated wheat anther cultures resulting in plants with increased Al tolerance

The in vitro selection of microspores and microspore‐derived structures under Al stress is one way to improve the Al tolerance of crops. In our study, cytological alterations caused by Al were examined in anther cultures of a commercial wheat (Triticum aestivum L.) variety ‘Mv Pálma’, and the efficiency of in vitro selection was demonstrated. Although the anther walls retarded the appearance of toxicity symptoms, cytological changes similar to those observed in root cells (inhibition of cell division, intense vacuolisation, occurrence of micronuclei and cell wall thickening) were detected in the microspores. The severity of Al toxicity and the efficiency of selection depended on the Al concentration and the mode of treatment. Single Al treatments (0.6 and especially 1.6 mM) allowed DH lines with increased Al tolerance to be selected. Repeated Al treatment severely inhibited the cell division of the microspores and it was lethal even at a concentration as low as 0.6 mM. The results show that microspore embryogenesis can be exploited for studying the cytological effect of Al and for increasing the Al tolerance of wheat.     

Barley mutants with increased tolerance to aluminium toxicity

Acid soil and associated aluminium toxicity are considered as the number one abiotic factor limiting crop production. Over 2 billion hectares of acid soils exist world-wide, both in tropical and moderate climatic zones. In Poland acid soils represent up to60% of arable land. At soil pH < 5.0 Al ions become soluble in water and toxic to plants. Genetic improvement of Al tolerance in crops is the only alternative to soil liming, a traditional but short term and expensive agricultural cure to raise soil pH. Of the various cereals, barley is the most sensitive to Al toxicity. The known sources of Al tolerance in barley are limited to old cultivars and landraces. While they represent multiple alleles of a single locus, there is no potential to improve Al tolerance through recombination of non-allelic additive genes. In the Department of Genetics, Silesian University we have employed induced mutations for rapid creation of variability for Al tolerance in barley. Thirteen mutants with increased levels of tolerance to Al toxicity have been selected in M₃ generation after mutagenic treatment of four barley varieties with N-methyl-N-nitroso urea (MNH) and sodium azide. Six further Al tolerant mutants were identified in the collection of semi-dwarf mutants of the Department. All selected mutants confirmed Al tolerance with the use of three different methods of screening, i.e., root re-growth, root tolerance index and hematoxylin staining. Fourteen mutants exhibited significant root re-growth after 48 hour incubation with 3 ppm Al⁺³ and two of them, namely RL819/2 and RL820/6 were tolerant even to 6 ppm Al⁺³. Crosses of two selected mutants with their respective parent varieties indicated that Al tolerance in each mutant was controlled by a single recessive gene. Out of three methods tested, the root re-growth method facilitated by hematoxylin staining proved to be the most reliable technique for large scale testing. Double treatment with MNH or combined treatment with sodium azide and MNH and 6hinter-incubation germination between treatments were the most successful treatment combinations for induction of aluminium tolerance in barley. This revised version was published online in August 2006 with corrections to the Cover Date.     

Molecular mapping of quantitative trait loci (QTLs) controlling aluminium tolerance in bread wheat

Aluminium (Al) toxicity is a major constraint to crop productivity in acidic soils. A quantitative trait locus (QTL) analysis was performed to identify the genetic basis of Al tolerance in the wheat cultivar ‘Chinese Spring’. A nutrient solution culture approach was undertaken with the root tolerance index (RTI) and hematoxylin staining method as parameters to assess the Al tolerance. Using a set of D genome introgression lines, a major Al tolerance QTL was located on chromosome arm 4DL, explaining 31% of the phenotypic variance present in the population. A doubled haploid population was used to map a second major Al tolerance QTL to chromosome arm 3BL. This major QTL (Qalt _CS .ipk-3B) in ‘Chinese Spring’ accounted for 49% of the phenotypic variation. Linkage of this latter QTL to SSR markers opens the possibility to apply marker-assisted selection (MAS) and pyramiding of this new QTL to improve the Al tolerance of wheat cultivars in breeding programmes.     

Enhancement of aluminum tolerance in wheat by addition of chromosomes from the wild relative Leymus racemosus

Aluminum (Al) toxicity is the key factor limiting wheat production in acid soils. Soil liming has been used widely to increase the soil pH, but due to its high cost, breeding tolerant cultivars is more cost-effective mean to mitigate the problem. Tolerant cultivars could be developed by traditional breeding, genetic transformation or introgression of genes from wild relatives. We used 30 wheat alien chromosome addition lines to identify new genetic resources to improve wheat tolerance to Al and to identify the chromosomes harboring the tolerance genes. We evaluated these lines and their wheat background Chinese Spring for Al tolerance in hydroponic culture at various Al concentrations. We also investigated Al uptake, oxidative stress and cell membrane integrity. The L. racemosus chromosomes A and E significantly enhanced the Al tolerance of the wheat in term of relative root growth. At the highest Al concentration tested (200 μM), line E had the greatest tolerance. The introgressed chromosomes did not affect Al uptake of the tolerant lines. We attribute the improved tolerance conferred by chromosome E to improved cell membrane integrity. Chromosome engineering with these two lines could produce Al-tolerant wheat cultivars.     

Inheritance and chromosome location of Alp, a gene controlling aluminum tolerance in 'Dayton' barley

Aluminum (Al) toxicity is a major limiting factor in acid soils and more adequate genetic tolerance is needed to improve barley adaptation and production in affected regions. To study the inheritance and chromosome location of the Alp gene controlling Al tolerance in ‘Dayton’ barley the primary trisomics of sensitive ‘Shin Ebisu 16’ were crossed to ‘Dayton’. Parental, F₁ and F₂ seedlings were grown in nutrient solution containing 0.03, 0.06 and 0.09mM Al. and classified for tolerance by haematoxylin staining of the roots. In diploid F₂ progeny, Alp was inherited as a single gene, dominant at 0.06mM and recessive at 0.09 mM concentrations, as indicated by the 3:1 and 1:3 (tolerant: sensitive) segregation ratios, respectively. Segregation of the trisomic Frderived F₂ seedlings at 0.06mM Al deviated significantly from the 3:1 only for the triplo 4/‘Dayton’ cross. Data for this cross fit the expected trisomic ratios, indicating that the Alp gene is distally located from the centromere on chromosome 4. These results confirm that tolerance is simply inherited, but expression of tolerance is dependent on Al concentration and allele dose.     

超量表达苹果酸脱氢酶基因提高苜蓿对铝毒的耐受性

在酸性土壤中,铝毒是许多作物正常生产的主要限制因子。虽可通过施用生石灰来改良土壤酸碱度,但只能改善土壤表层,在实际应用中受到很大限制。紫花苜蓿作为一种非常重要的牧草、饲料,在酸性土壤条件下苜蓿生长缓慢甚至死亡。我国南方水热资源丰富,但土壤多偏酸性,限制了苜蓿南移。有机酸能螯合铝离子,减轻铝对植物根系的危害。苹果酸是游离铝离子的有效螯合剂,而苹果酸脱氢酶(Malate Dehydrogenase,MDH)催化草酰乙酸形成苹果酸。本研究在苜蓿中超量表达苹果酸脱氢酶基因,通过抗生素筛选、组织化学染色和PCR扩增等技术鉴定出转化植株,并对转化株系进行了耐铝胁迫试验,比较分析了转基因株系与非转基因株系的的相对伸长量,转基因株系根相对伸长量比对照高出3．6％～22．5％。说明超量表达neMDH基因可提高了转基因苜蓿对铝毒的耐受性。