Sarma S S, Ramírez-Pérez T, Nandini S, Peñalosa-Castro I
Division of Biology, National Autonomous University of Mexico, Campus Iztacala, AP 314, CP 54090, Tlalnepantla, State of Mexico, Mexico.
Ecotoxicology. 2001 Apr;10(2):91-9. doi: 10.1023/a:1008997908784.
Herbicides are important in crop protection and management. A number of them including 2,4-D (2,4-dichlorophenoxyacetic acid), however, may reach water bodies and eventually affect the non-target organisms such as rotifers. In the present work, we studied the influence of 6 concentrations viz. 0 (control), 100, 200, 300, 400 and 500 mg l-1 of 2,4-D on the population growth of the rotifer Brachionus patulus under two algal (Chlorella) food levels (0.5 x 10(6) and 1.5 x 10(6) cells ml-1). Regardless of herbicide concentration, the population growth of B. patulus was dependent on the algal food levels, in that an increase in algal food level supported a better population growth. Similarly at any Chlorella density, the herbicide had a negative influence on the population growth of B. patulus. Herbicide level of 500 mg l-1 inhibited population growth of B. patulus beyond 5 days. Rotifers grown under low food density and high herbicide concentration (300 mg l-1 or above) were completely eliminated after day 15. The rate of population increase (r) (mean +/- standard error) in the controls varied from 0.46 +/- 0.002 and 0.55 +/- 0.004 under 0.5 x 10(6) and 1.5 x 10(6) cells ml-1 of Chlorella, respectively. The r values became negative under both, low and high food levels, at or beyond 300 mg l-1 of 2,4-D. The maximal population abundance (ind. ml-1) in controls varied from 294 +/- 9 to 503 +/- 21 under low and high food levels of Chlorella, respectively. The role of algae in mitigating adverse effects of high herbicide concentrations to rotifers has been discussed.
除草剂在作物保护和管理中很重要。然而，其中一些除草剂，包括2,4-二氯苯氧乙酸（2,4-D），可能会进入水体并最终影响轮虫等非目标生物。在本研究中，我们研究了6种浓度（即0（对照）、100、200、300、400和500 mg l-1）的2,4-D在两种藻类（小球藻）食物水平（0.5×10⁶和1.5×10⁶个细胞 ml-1）下对扁形臂尾轮虫种群增长的影响。无论除草剂浓度如何，扁形臂尾轮虫的种群增长都依赖于藻类食物水平，即藻类食物水平的增加支持更好的种群增长。同样，在任何小球藻密度下，除草剂对扁形臂尾轮虫的种群增长都有负面影响。500 mg l-1的除草剂水平在5天后抑制了扁形臂尾轮虫的种群增长。在低食物密度和高除草剂浓度（300 mg l-1及以上）下生长的轮虫在第15天后被完全消灭。对照中种群增加率（r）（平均值±标准误差）在0.5×10⁶和1.5×10⁶个细胞 ml-1的小球藻下分别为0.46±0.002和0.55±0.004。在2,4-D浓度为300 mg l-1及以上时，无论食物水平高低，r值均变为负值。对照中最大种群丰度（个/ml-1）在小球藻低食物水平和高食物水平下分别为294±9和503±21。本文还讨论了藻类在减轻高浓度除草剂对轮虫的不利影响方面的作用。
