不同水分条件与重金属复合处理对铺地黍生长的影响

鉴于污染河岸消落带生态修复的紧迫性及其干湿交替生境的特殊性,本研究针对铺地黍(Panicum repens L.)在同时受到水分和重金属复合胁迫下的形态和生理特性变化展开研究,以期为构建铺地黍-消落带生态系统提供理论与实践参考。试验采用盆栽,设置5种水分+重金属复合处理。结果显示,在铺地黍株高和分枝数形态特征方面,相对于CK,水淹+低浓度重金属复合处理下的42天总体平均值高于CK,促进了生长;水淹+高浓度重金属的总体平均值虽低于CK,但差异不显著(P0.05),整个试验期均正常生长。干旱+低浓度重金属和干旱+高浓度重金属处理下的株高和分枝数都受到严重影响,处理14天植株叶片开始出现萎蔫,21天大部分植株干枯,35天(干旱+低浓度)和28天(干旱+高浓度)地上部死亡。在铺地黍生理响应方面,水淹+重金属条件下的叶片游离脯氨酸和丙二醛含量与CK之间的差异均不显著(P0.05),即植株受伤害程度不大。但是,干旱+重金属条件下的叶片游离脯氨酸和丙二醛产生了积极响应,均显著高于CK(P0.05)。

Compound Treatment Effects of Water and Heavy Metal on Growth of Panicum repens L.

Studies on the morphological and physiological properties of Panicum repens L. were conducted under both water and heavy metal stress, in view of the urgency of eco-restoration of hydro-fluctuation belts of polluted rivers and their special alternation environment of wetting and drying, to provide references for constructingPanicum repens L.-hydro-fluctuation belt ecological system. This experiment was conducted with pot- cultured method and 5 treatments compositing 2 factors of water and heavy metal were adopted. The results showed that: the total average values of the plant absolute height and branch number ofPanicum repens L. under the low-Cd-Pb-and-flooded treatment with 42 days were higher than that under CK; in addition, although the total average of the plant absolute height and branch number ofPanicum repens L. under high- Cd-Pb-and-flooded treatment were lower than that under CK, but the differences between H-Cd-Pb-flooded treatment were not significant (P >0.05), i.e.Panicum repens L. could maintain normal growth; however, the plant absolute height and branch number ofPanicum repens L. were inhibited under both L-Cd-Pb-drought and H-Cd-Pb-drought treatments; during the experiments under Cd-Pb-drought treatments, the plant had wilt phenomenon in 14 days, and then leaf blade was dry in 21 days, even all the plants were dead in 35 days for those under L-Cd-Pb-drought and in 28 days for those under H-Cd-Pb-drought; as for the physiological features, the proline content and malondialdehyde content under both L-and H-Cd-Pb-flooded treatments were all close to those values under CK and the differences between Cd-Pb-flooded treatments and CK were not significant (P >0.05), which indicated that the hurt from Cd-Pb-flooded treatment were light; however, the proline and malondialdehyde content under both L-and H-Cd-Pb-drought treatments were all significantly higher than those values under CK (P >0.05), which suggested a very active physiological response ofPanicum repens L. to L-and H-Cd-Pb-drought treatments.