赤潮异弯藻和海洋卡盾藻抗氧化酶活性对氮磷比失衡的响应

Response of antioxidant enzyme activities in Heterosigma akashiwo and Chattonella marina to lose-balance of N/P ratio

超氧化物歧化酶(SOD)和过氧化氢酶(CAT)是浮游植物抗氧化酶系统的重要组成部分,可有效消除因环境胁迫产生的活性氧自由基对细胞的损伤。本文通过研究氮磷比失衡状态下赤潮异弯藻和海洋卡盾藻的生长及其SOD与CAT酶活性的变化,探索了赤潮物种抗氧化酶对氮磷比失衡的响应。研究表明:N和P限制不仅抑制了赤潮异弯藻和海洋卡盾藻的生长,而且显著提高了SOD与CAT酶活性。酶活性对营养盐失衡的响应随营养盐类型和藻类种类不同而有所差异:赤潮异弯藻对P限制最为敏感,其SOD和CAT酶活性在P限制下显著高于N限制;而N限制和P限制对海洋卡盾藻抗氧化酶活性的影响并无差异。抗氧化酶活性的调控能够有效降低氮磷比失衡对藻类细胞的生理损伤,有利于藻华的发生和规模的维持。

The antioxidant enzymes of phytoplankton include CAT and SOD, which can alleviate the cellular oxidative damage by scav- enging ROS species. The responses of activities of CAT, SOD in Heterosigma akashiwo and Chattonella marina to the nutrient limita- tion were investigated. The results showed that N-depletion depressed the growth and stimulated the activities of CAT and SOD in H. akashiwo and C. marina. The variation in the response of activities of SOD and CAT to the nutrition limitation was species-specific. The activities of SOD and CAT in H. akashiwo when exposed to the P-depletion were higher than N-depletion, however, both N-limi- tation and P-limitation insignificant impacted the activities of SOD and CAT in C. marina. The antioxidant enzymes appareutly allevi- ate the potential damage caused by the nutrition limitation, thus the development and maintenance of harmful algae bloom need the help.