玉米根冠粘胶和铝的结合及有机酸累积

Root-cap Mucilage Binds Aluminum and Accumulates Organic Acids in Zea mays L.

玉米根系分泌较多的植物粘胶 ,用 0 .0 1%中性红溶液使粘胶染成红色。 30 μmol/L的AlCl3 处理根系 1h后 ,不除去粘胶的根尖的铝含量大于除去粘胶的根尖的铝含量。粘胶的铝含量随着处理的铝浓度的增加而增加。用高效液相色谱仪能使粘胶 铝复合物分离成均含糖和铝的两种组分。 5 μmol/L的AlCl3 处理根系 2 4h后 ,粘胶中积累了铝诱导分泌的有机酸。粘胶中含有酸性磷酸酶 ,它的活性随着处理的铝浓度的增加而降低。这些结果证明了植物粘胶能够和铝结合。

Mucilage, which could be stained by 0.01% neutral red, was found on the root tip of Zea mays (Fig.1). After roots were exposed to 30 μmol/L AlCl 3 solution for 1 h, Al content in the tips of roots with mucilage was higher than those of roots without it (Fig.2). In vitro , the amount of Al in mucilage increased with the concentration of Al used (Fig.3). The mucilage Al complex was separated with HPLC to two fractions (Fig.4). Organic acids were found in the mucilage when roots were treated with AlCl 3 5 μmol/L for 24 h to induce their secretion (Fig.5). Acid phosphatase was also found in the mucilage, the activity of which decreased with the concentration of Al used (Fig.6) . This study supports the binding of Al to mucilage, accumulations of organic acids and acid phosphatase in mucilage droplet.