Physiological responses of three Wild Polygonaceae plants to aluminum stress | 3种野生蓼科植物对铝胁迫的生理响应

Chinese. 摘　　要：用水培法，设置0、25、50、100、400μmol／L5种AlCl3浓度处理，研究了3种野生蓼科植物酸模叶蓼、杠板归和辣蓼对铝胁迫的生理响应。结果表明：3种蓼科植物相对根系伸长率都随A1Cl3浓度的增加呈递减的趋势，但A1Cl3对杠板归根伸长的抑制程度要明显高于酸模叶蓼和辣蓼，表明酸模叶蓼和辣蓼的耐铝性显著高于杠板归；3种蓼科植物根系铝含量和草酸分泌量均随AICl3浓度的增加而增加（其中杠板归和辣蓼根系草酸分泌量在AICl3为50μmol／L时达到饱和），但酸模叶蓼和辣蓼根系铝含量显著低于杠板归，而根系草酸分泌量显著高于杠板归；高浓度（400μmol／L）处理使3种蓼科植物根系活力、叶片过氧化物酶（POD）和过氧化氢酶（CAT）活性显著下降，丙二醛（MDA）含量显著升高，尤以杠板归变化最为明显。而低浓度（25-50μmol／L）处理时，酸模叶蓼和辣蓼根系活力表现出递增的趋势，叶片脯氨酸含量、过氧化物酶和过氧化氢酶活性较对照显著升高，丙二醛含量显著下降。由此说明，酸模叶蓼和辣蓼在低浓度AlCl3胁迫下可通过外部排斥（铝诱导的根系草酸分泌）和内部解铝毒（提高根系活力、叶片POD和CAT活性、脯氨酸含量及降低MDA含量）2种途径来增强其对铝的耐性。

English. Three wild polygonaceae plants, Polygonum lapathifolium, Polygonum perfoliatum and Polygonurn hydropiper,were used to study the physiological responses under five aluminum （AlCl3） concentrations （0,25,50,100,400μmol/L） with solution culture method. It was found that relative root elongation was decreased with the increase of AlCl3 concentrations in polygonaceae plants,but the magnitude of decrease was higher in Polygonum perfoliatum than that in Polygonum lapathifolium and PoLygonum h ydropi per , suggesting that PoLygonurn la pathi folium and PoLygonum hydropiper were much more tolerant to Al than Polygonum perfoliatum was. A1 contents and oxalate secretion in roots of three polygonaceae plants were increased with increase of AlCl3 concentraions and oxalate secretion showed that a saturating phenomenon at approximately 50μmol/L AlCl3 in PoLygonum hydropiper and Polygohum perfoliatum, while A1 contents were significantly lower and the amount of oxalate secretion significantly higher in Polygonum lapathifolium and Polygonurn hydropiper than that in Polygonum perfoLiatum. When compared with the control,high AlCl3 treatment （400 μmol/L） significantly decreased root activity,leaf activities of peroxides （POD） and catalase （CAT）,increased malondialdehyde （MDA） con- tent of three polygonaceae plants, especially in Polygonum perfoliatum. In the low concentration of AlCl3 treatments （25-50 μmol/L）, root activity in Polygonum lapathifoliurn and Polygonum hydropiper showed an increasing trend, and leaf proline content, activities of POD and CAT significantly increased,MDA content significantly decreased compared with the control. These findings suggested that Polygonum lapathifoliurn and Polygonum hydropiper could enhance the tolerance to A1 stress by increasing Al-induced oxalate secretion and maintaining higher proline content, higher activities of POD and CAT,lower MDA content under the low AlCl3 concentration.