Bittencourt-Oliveira M C, Hereman T C, Macedo-Silva I, Cordeiro-Araújo M K, Sasaki F F C, Dias C T S
Department of Biological Sciences, Luiz de Queiroz College of Agriculture, Universidade de São Paulo, Piracicaba, SP, Brazil.
Graduating Program on Biological Sciences, Universidade Estadual Paulista "Júlio de Mesquita Filho", Rio Claro, SP, Brazil.
Braz J Biol. 2015 May;75(2):273-8. doi: 10.1590/1519-6984.08113.
We evaluated the effect of crude extracts of the microcystin-producing (MC+) cyanobacteria Microcystis aeruginosa on seed germination and initial development of lettuce and arugula, at concentrations between 0.5 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent, and compared it to crude extracts of the same species without the toxin (MC-). Crude extracts of the cyanobacteria with MC (+) and without MC (-) caused different effects on seed germination and initial development of the salad green seedlings, lettuce being more sensitive to both extracts when compared to arugula. Crude extracts of M. aeruginosa (MC+) caused more evident effects on seed germination and initial development of both species of salad greens than MC-. Concentrations of 75 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent induced a greater occurrence of abnormal seedlings in lettuce, due to necrosis of the radicle and shortening of this organ in normal seedlings, as well as the reduction in total chlorophyll content and increase in the activity of the antioxidant enzyme peroxidase (POD). The MC- extract caused no harmful effects to seed germination and initial development of seedlings of arugula. However, in lettuce, it caused elevation of POD enzyme activity, decrease in seed germination at concentrations of 75 μg.L(-1) (MC-75) and 100 μg.L(-1) (MC-100), and shortening of the radicle length, suggesting that other compounds present in the cyanobacteria extracts contributed to this result. Crude extracts of M. aeruginosa (MC-) may contain other compounds, besides the cyanotoxins, capable of causing inhibitory or stimulatory effects on seed germination and initial development of salad green seedlings. Arugula was more sensitive to the crude extracts of M. aeruginosa (MC+) and (MC-) and to other possible compounds produced by the cyanobacteria.
我们评估了产微囊藻毒素（MC+）的铜绿微囊藻粗提物对生菜和芝麻菜种子萌发及初期发育的影响，其微囊藻毒素-LR（MC-LR）当量浓度在0.5 μg.L⁻¹至100 μg.L⁻¹之间，并将其与不含毒素的同物种粗提物（MC-）进行了比较。含MC（+）和不含MC（-）的蓝藻粗提物对沙拉绿色幼苗的种子萌发和初期发育产生了不同影响，与芝麻菜相比，生菜对两种粗提物都更敏感。铜绿微囊藻（MC+）的粗提物对两种沙拉绿色植物的种子萌发和初期发育产生的影响比MC-更明显。75 μg.L⁻¹和100 μg.L⁻¹的MC-LR当量浓度导致生菜中异常幼苗的发生率更高，这是由于正常幼苗的胚根坏死和该器官缩短，以及总叶绿素含量降低和抗氧化酶过氧化物酶（POD）活性增加。MC-粗提物对芝麻菜幼苗的种子萌发和初期发育没有有害影响。然而，在生菜中，它导致POD酶活性升高，在75 μg.L⁻¹（MC-75）和100 μg.L⁻¹（MC-100）浓度下种子萌发率降低，胚根长度缩短，这表明蓝藻提取物中存在的其他化合物促成了这一结果。铜绿微囊藻（MC-）的粗提物除了蓝藻毒素外，可能还含有其他能够对沙拉绿色幼苗的种子萌发和初期发育产生抑制或刺激作用的化合物。芝麻菜对铜绿微囊藻（MC+）和（MC-）的粗提物以及蓝藻产生的其他可能化合物更敏感。
