塔玛亚历山大藻对重金属铜的生理响应

Physiogical Response of Alexandrium tamatense to Heavy Metal Copper

针对铜离子(Cu^(2+))污染海洋环境中塔玛亚历山大藻作为优势种广泛分布的现状,本研究以塔玛亚历山大藻(Alexandrium tamarense)为研究对象,深入探究了不同铜离子(Cu^(2+))浓度(0、20、40、80和160 nmol/L)培养下塔玛亚历山大藻生长、叶绿素、光合作用以及抗氧化系统的变化,揭示了塔玛亚历山大藻对Cu^(2+)的生理响应机制。实验结果表明,塔玛亚历山大藻生长和光合作用的最适Cu^(2+)浓度为40 nmol/L。低于此浓度,塔玛亚历山大藻的生长和光合作用受到轻微抑制。而高浓度Cu^(2+)(80和160 nmol/L)处理下,在培养前5 d内会导致藻的生理机能严重受损,生长受到抑制,光合能力下降,活性氧含量增加,抗氧化酶活性和抗氧化剂含量增加;培养5 d后,塔玛亚历山大藻的生长速度和叶绿素含量逐渐增加,光合能力逐渐增强。这表明高浓度Cu^(2+)胁迫在初期(短期内)会诱导藻体内抗氧化酶活性和抗氧化剂含量的升高,从而增强其对Cu^(2+)的耐受性,随着Cu^(2+)的消耗和玛亚历山大藻对环境的逐渐适应,该藻的生长和光合作用恢复正常生长。综上所述,塔玛亚历山大藻对高浓度Cu^(2+)胁迫具有一定的耐受性,这增加了该藻在Cu^(2+)污染的环境中的竞争力。

Aimed at the situation of the Alexandrium tamarense distribution as the dominant species in Cu polluted marine environment we deeply investigate the change of growth,chlorophyll,photosynthesis,and antioxidant system of A.tamarense cultured at different Cu^(2+)concentrations(0、20、40、80 and 160 nmol/L),which could reveal the physiological response of A.tamarense to Cu^(2+).The results showed that the optimum concentration of Cu^(2+)for growth and photosynthesis was 40 nmol/L,below which the growth and photosynthesis of A.tamarense were slightly inhibited.The higher Cu^(2+)concentration(80 and 160 nmol/L)could induce the impairment of physiological functions,inhibition of the growth,decrease of photosynthetic capacity,enhancement of reactive oxygen and antioxidant oxidase content in the first 5 days.However,the growth rate,chlorophyll content,and photosynthetic capacity increased gradually after 5 days.That indicated the high Cu^(2+)concentration could result in the improvement of the activity of antioxidant enzyme and antioxidant in alga,further enhancing the tolerance of A.tamarense to Cu^(2+).With the consumption of Cu^(2+)and adaptation to the environment,the growth and photosynthesis of A.tamarense could be recovered.In conclusion,A.tamarense exhibited a significant tolerance to the high Cu^(2+)concentration,and enhanced the competitiveness of A.tamarense in Cu-contaminated environment.