Umebese C E, Motajo A F
Department of Botany and Microbiology, University of Lagos, Akoka Yaba, Lagos, Nigeria.
J Environ Biol. 2008 Mar;29(2):197-200.
Ceratophyllum demersum (homwort) was subjected to toxic concentrations of Al (3 and 9 mg l(-1)), Zn (3 and 9 mg l(-1)) and Cu (2.5 and 7 mg l(-1)) in culture solutions for 15 days. The higher dose of Al enhanced the chlorophyll content significantly (p<0.05) in the first 6 days of treatment while other treatments caused marked reductions. Nitrate reductase activity (NRA) was significantly reduced (p<0.05) byAl, Cu and Zn toxicity and ceased completely in plants treated with Cu by the 6th day of treatment. Dry biomass and relative growth rate were reduced significantly (p<0.05) by metal treatment. Tolerance index of the plant was low for Cu (21.62 and 13.43% at low and high doses, respectively) and moderate for Zn (63.74 and 54.85%) and Al (72.83 and 68.79%). Accumulation ofAl, Zn and Cu was threefold at higher doses compared with the lower doses but the bioconcentration factors (BCF) were very low indicating that this plant is not a hyper accumulator of these metals.
金鱼藻在培养液中分别经受了有毒浓度的铝（3和9毫克/升）、锌（3和9毫克/升）和铜（2.5和7毫克/升）处理15天。较高剂量的铝在处理的前6天显著提高了叶绿素含量（p<0.05），而其他处理则导致显著降低。铝、铜和锌的毒性显著降低了硝酸还原酶活性（NRA）（p<0.05），并且在处理第6天时，用铜处理的植物中硝酸还原酶活性完全停止。金属处理显著降低了干生物量和相对生长率（p<0.05）。该植物对铜的耐受指数较低（低剂量和高剂量分别为21.62%和13.43%），对锌（63.74%和54.85%）和铝（72.83%和68.79%）的耐受指数为中等。与较低剂量相比，较高剂量时铝、锌和铜的积累量增加了两倍，但生物富集系数（BCF）非常低，表明该植物不是这些金属的超富集植物。
