铀胁迫对油菜的生长及抗氧化酶的影响

Uraniuminduced effects on development and antioxidase of Brassica napus L.

以甘蓝型油菜为实验材料,分析了在铀胁迫下油菜的生理生化指标,相关抗氧化酶的活性,及相关基因表达的变化.研究结果表明,油菜的种子萌发率,幼苗株高和鲜重并未随着铀胁迫浓度的增加而降低,而随着胁迫浓度和时间的增加,幼苗根长会受到显著影响.铀胁迫对油菜的离子渗漏和脂质过氧化影响很大,在胁迫下油菜幼苗的相对电导率可增加120.6%,丙二醛的含量可达对照的25倍.从几种抗氧化酶的活性变化情况看,随着铀浓度的增加,超氧化物歧化酶(SOD),过氧化物酶(POD)和过氧化氢酶(CAT)的活性都有所下降,而且胁迫浓度和时间越多,酶活下降越多.通过分析几种抗氧化酶相关基因的表达量,发现CAT1和APX的表达量在所有胁迫条件下都下调,而CSD1则在较低浓度时上调表达,较高浓度时下调表达.

This research aimed to study effects on growing development and alterations in transcriptional and protein level of some ROS-scavenging enzymes for Brassica napus seedlings following uranium expo- sure. The results showed that compared with control group, fresh weight, height and germination rate of Brassica napus seedlings did not decrease with increasing uranium stress concentration, but the root length was significantly affected as the treatment of elevated concentrations and suppression time. Ura- nium exposure caused an obvious change in ion leakage and lipid peroxidation, significantly increasing has been observed in relative electrical conductivity（120.6%） and content of malondialdehyde（about 25 times）. Analysis of ROS-scavenging enzymes capacities as SOD, POD and CAT showed sharply de- creased when concentration and time of uranium contamination stress were increased. Changes in gene expression for different ROS-scavenging enzymes as CAT1 ,APX and CSD1 has been analysed,and tran- script levels of CAT1 and APX were significantly down-regulated under any uranium concentration. In-terestingly , the expression of CSD1 was up-regulated under low uranium concentration,but its expres- sion was down-regulated when exposed to high uranium concentration.