微囊藻毒素对水稻种子萌发和幼苗生长的胁迫作用

Inhibitory effect of microcystins on seed germination and seedling growth of rice

为了明确微囊藻毒素污染的农用灌溉水对水稻生长的潜在威胁,研究了微囊藻毒素MC-LR对水稻种子萌发和水稻幼苗生长的影响。结果显示：低浓度MC-LR（0.05-100μg/ml）对水稻种子萌发无显著影响,高浓度MC-LR（500μg/ml）则显著抑制种子萌发（P〈005）;水稻种子淀粉酶活性随着MC-LR处理浓度的升高而逐渐降低（P〈005）;随着MC-LR处理浓度的升高,MC-LR在水稻幼苗体内的累计量逐渐升高,但生物富集系数逐渐降低,水稻幼苗地下部分的MC-LR累积量高于地上部;MC-LR处理显著抑制水稻幼苗的生长（P〈005）,且水稻幼苗的长势与其体内累积的MC-LR量呈显著负相关（P〈005）;005μg/ml的MC-LR处理不影响水稻幼苗体内MDA含量和抗氧化酶（SOD、CAT、POD）的活性,而0.10-500μg/ml的MC-LR处理则导致上述生化指标的显著上升。表明,MC-LR胁迫能够抑制水稻种子萌发,并在水稻幼苗体内显著累积,诱导氧化损伤,抑制幼苗生长。

To investigate the potential risk of microcyntin-contaminated water on the grow-th of rice, the effect of MC-LR on seed germination and seedling growth of rice was investigated. MC-LR at low concentration （0.05-1. 00 pg./ml） exhibited no influence on the germination of rice seed ＂while MC-LR at high concentration （5. 00 pg/ml） significantly inhibited the germination （ P〈0. 05）. Treatment with MC-LR significantly inhibited the activity of amylase in rice seed in a dose- dependent manner （P〈0. 05）. The increase in MC-LR concentration resulted in the increase in MC-LR concentration in rice seedlings but the decrease in bioconcentration factor of MC-LR in rice seedlings. The roots accumulated more MC-LR than shoots. Treatment with MC-LR remarkably inhibited the growth of rice seedlings （ P〈0. 0 5 ） ,and a significantly negative correlation was found between MC-LR concentration in seedlings and the growth of seedlings （ P〈 0. 0 5 ） . The oxidative indices,such as MDA concentration and the activities of antioxidative enzymes （ SOD, CAT, and POD）,were not affected by MC-LR at low concentration （0. 05 μg/ml ）. However, MC-LR at 0.10-5.00 μg/ml significantly induced the increase in the oxidative indices. Taken together, MC-LR stress inhibited seed germination and seedling growth of rice by decreasing the activity of amylase in rice seed and inducing oxidative injury in rice seedling.