水稻和小麦根尖细胞壁多糖的铝积累能力比较

采用水培法比较4种禾本科植物水稻（Oryza sativa L.）、玉米（Zea mays L.）、高粱（Sorghum bicolor（L.）Moench）和小麦（Triticum aestivum L.）8个基因型的抗铝（Al）能力，并对他们在Al积累后细胞壁的多糖组分进行分析。结果显示，在5~200 μmol/L Al处理下，水稻抗Al能力较强，而小麦抗Al能力较弱。在50 μmol/L Al处理下，小麦根尖的果胶和半纤维素1含量的增幅明显高于水稻。水稻基因型‘日本晴’与‘浙辐802’的细胞壁Al含量分别占根尖总Al含量的78.7%和91.6%；小麦基因型‘扬麦18’与‘扬麦16’Al含量分别占根尖总Al含量的64.9%和72.1%。Al吸附-解吸实验结果显示，小麦根尖细胞壁上Al的吸附量高于水稻。研究结果表明，细胞壁是Al积累的主要部位，对Al敏感的水稻和小麦基因型细胞壁中的Al主要分布在果胶中；而对Al耐性较强的水稻和小麦基因型细胞壁中的Al主要分布在半纤维素1中。

Comparison of aluminum accumulation ability of cell wall polysaccharides in Oryza sativa and Triticum aestivum root tips under aluminum toxicity

Hydroponics were used to compare eight genotypes of four Poaceae plants (Oryza sativa L., Zea mays L., Sorghum bicolor (L.) Moench, and Triticum aestivum L.). We investigated their resistance to aluminum (Al) and analyzed the polysaccharide components of the cell wall after Al accumulation. Results revealed that under 5-200 μmol/L Al treatment, rice exhibited the strongest Al resistance, whereas wheat demonstrated the weakest, thus further experiments were carried out on rice and wheat. Under 50 μmol/L Al treatment, the content of pectin and hemicellulose 1 was higher in the wheat root tips than that in the rice root tips. Furthermore, Al content in the cell wall of ‘Nipponbare’ and ‘Zhefu 802’ seedlings accounted for 78.7% and 91.6% of that in the root tips, and in ‘Yangmai 18’ and ‘Yangmai 16’ seedlings accounted for 64.9% and 72.1% of that in the root tips. The Al adsorption-desorption tests further showed that Al uptake in the wheat root tip cell wall was higher than that for rice, whereas the desorption rate was lower than that for rice. The cell wall was the main site for Al accumulation, the pectin component in the cell wall was the major binding site of Al-sensitive rice and wheat genotypes, and the hemicellulose 1 component was the major binding site of Al-tolerant rice and wheat genotypes.