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首页> 外文会议>Consultants Meeting on Management Practices for Improving Sustainable Crop Production in Tropical Acid Soils >IDENTIFICATION AND CHARACTERIZATION OF ALUMINIUM-RESISTANT, PHOSPHORUS-EFFICIENT PLANT GENOTYPES ADAPTED TO TROPICAL ACID SOILS
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IDENTIFICATION AND CHARACTERIZATION OF ALUMINIUM-RESISTANT, PHOSPHORUS-EFFICIENT PLANT GENOTYPES ADAPTED TO TROPICAL ACID SOILS

机译：耐铝，磷的耐高效植物基因型适用于热带酸性土壤的鉴定及表征

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In most tropical acid soils, aluminium (Al) toxicity and phosphorus (P) deficiency are the most important factors limiting plant growth and crop yields. One of the key elements of sustainable cropping systems on these soils is the integration of crops and/or crop cultivars with high Al resistance and P efficiency. Experimental activities on enhancing plant P efficiency concentrated on the characterization of the P mobilising capacity of different leguminous grain and cover crops, and their effect on P availability to less P-efficient cereals grown in mixed culture and in rotation. Fractionation of P in the rhizosphere soil revealed the capacity of some legumes to better use P from sparingly soluble soil P fractions than maize. Field experiments conducted on 2 sites in the Northern Guinea Savannah of Nigeria and accompanying green-house pot-experiments revealed a positive rotational effect of P-efficient cover crops on maize growth and grain yield with and without return of crop residues. This could be attributed to a better P supply to maize especially on the strongly P-fixing soil. Experimental work related to Al toxicity and resistance focussed on the development of a selection technique for Al resistance and thus adaptation to acid soils, the genetics of Al resistance in maize, the role of cell-wall and plasma-membrane characteristics, and organic acid metabolism in Al resistance in maize, and the characterisation of differences in Al resistance in common bean. A 15x15 cultivars diallel was evaluated under field conditions and in hydroponics for Al-induced callose formation. The statistical analysis clearly showed that the General Combining Ability (GCA) rather than the Specific Combining Ability (SCA) is of major importance for Al resistance. Al-induced callose formation was negatively correlated to yields on acid soils. This screening technique proved to be a powerful tool in the identification of germplasm with high combining ability for adaptation to acid Al-toxic soils. Among the cell-wall properties the pectin content and its degree of methylation appeared to be of particular importance as indicated by a positive correlation between Al injury of root apices and pectin content and its degree of methylation. Silicon-induced amelioration of Al toxicity could be related to an in-planta effect. Al-treated plants accumulated higher amounts of Si in the root apical cell walls than non Al-treated plants, thus reducing the amount of the readily exchangeable Al in the cell walls. The importance of plasma-membrane properties for Al resistance was indicated by experiments with A8-sphingolipid desaturase-transformed maize plants which were more affected by Al than the wild-type, and differences in the degree of desaturation of fatty acids between a resistant and a sensitive maize cultivar. The changes were small, but experiments with yeast transformed with a 9-acyl desaturase showed that a small change in the degree of desaturation led to a very strong increase in Al resistance.
机译：在大多数热带酸性土壤，铝（Al）的毒性和磷（P）不足是限制植物生长和作物产量的最重要因素。一个在这些土壤可持续种植系统的关键因素之一是农作物和/或作物品种具有高Al电阻和P效率的整合。于提高植物P效率实验活动集中在不同豆科谷物和覆盖作物的P-动员能力，和它们对磷的有效性，以在混合培养物和在旋转生长更少的P-高效谷物效果的表征。在根际土壤P的分馏从难溶性土壤磷的分数比玉米透露了一些豆科植物的能力，以更好地利用P上。在尼日利亚北部几内亚大草原2位和相应的温室盆栽实验进行了现场实验表明磷高效覆盖作物对玉米生长和产量正旋转的效果与不作物秸秆的回报。这可能是由于更好的供磷对强P-固定土壤尤其是玉米。有关铝的毒性和性能试验的工作集中在一个选择技术的发展，为的Al阻力，从而适应酸性土壤，玉米耐铝，细胞壁和质膜特性的作用，和有机酸代谢的遗传学在玉米中的Al的电阻，并在常用的Al豆电阻差的表征。甲15×15品种双列在田间条件下，并在水培评价铝诱发的胼胝质的形成。统计分析清楚地表明，一般配合力（GCA），而不是特殊配合力（SCA）是非常重要的耐铝。人诱导的胼胝质的形成呈负在酸性土壤的产量相关。该筛选技术被证明是在识别种质具有用于适应酸铝毒性土壤配合力高的有力工具。间的细胞壁性质果胶含量和其甲基化程度似乎是特别重要的由根顶点的铝损伤和果胶含量和它的甲基化程度之间存在正相关所指示的。铝毒的硅引起的改善可能与一个在植物内的效果。铝处理的植物积累更高量的Si在根尖细胞壁比非铝处理过的植物，从而减少了单元壁的易更换的Al量。质膜性能为耐铝的重要性指示通过与A8-鞘脂去饱和酶转化的玉米植物，其比野生型中更受Al和抗性和之间的脂肪酸去饱和的程度的差异实验敏感的玉米品种。变化很小，但随着酵母的9酰脱氢酶转化实验表明，饱和度的微小变化导致铝阻力非常强的增长。

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