不同金属富集能力品系福建牡蛎铜、锌耐受性分析

Analysis of copper and zinc tolerance in the different metal accumulation ability strains of Crassostrea angulata

【背景】牡蛎具有强大的金属富集能力,被称为铜、锌超富集生物。同时,牡蛎在富集大量铜、锌后仍能正常存活,表现出超强的金属耐受能力。牡蛎对金属的富集能力存在显著的个体差异,是一种数量性状。目前已有采用富集动力学和全基因组关联分析等方法对牡蛎金属富集能力差异的机制进行解析的研究。但富集能力差异是否影响金属耐受性尚无定论。【目的】探究不同金属富集能力的福建牡蛎在不同发育阶段对铜、锌耐受性的差异。【方法】本研究利用福建牡蛎(Crassostrea angulata)高铜锌富集品系和低铜锌富集品系开展实验,测定不同品系福建牡蛎亲本的金属含量,并对两者D形幼体和6月龄成体进行铜、锌急性毒性实验,计算半致死浓度(LC_(50))。【结果】两品系间亲本的铜、锌含量均有显著差异;在D形幼体期,低富集品系幼体24 h的锌LC_(50)显著低于高富集品系幼体,24 h铜LC_(50)在两个品系中无显著差异,即高富集品系对锌的耐受性显著强于低富集品系,但两个品系对铜的耐受性无明显差异;在成体期,高富集品系成体96 h的铜、锌LC_(50)均高于低富集品系,即高富集品系对铜、锌的耐受性均显著强于低富集品系。【结论】福建牡蛎铜、锌富集能力越高,其耐受能力也越强,但受到了金属种类和生长发育阶段的影响,并且推测牡蛎在应对金属胁迫时,金属区域化隔离的解毒效率更高,也更适应环境的压力。【意义】本研究为探讨牡蛎金属富集能力与其耐受性间的联系奠定基础,并进一步为解析牡蛎金属富集和解毒机制提供参考。另外,研究牡蛎金属富集及耐受现象对保障食品安全以及利用牡蛎作为环境检测指示生物都具有重要意义。

[Background]Oysters possess formidable metal accumulation capabilities,earning them the title of hyperaccumulators of copper and zinc.Furthermore,they can survive normally even after accumulating significant amounts of these metals,demonstrating exceptional metal tolerance.Individual differences in oyster metal accumulation abilities are notably significant,representing a quantitative trait.Studies including enrichment kinetics and whole-genome association analyses have elucidated mechanisms underlying differences in oyster metal accumulation capabilities.However,whether these differences in accumulation capabilities affect metal tolerance remains inconclusive.[Objective]Investigating the differences in copper and zinc tolerance among oysters with varying metal accumulation capacities at different developmental stages.[Methods]This study utilized high copper-zinc accumulating strains and low copper-zinc accumulating strains of Fujian oysters(Crassostrea angulata)to conduct experiments.Metal contents in parental C.angulata of different strains were measured,and acute toxicity tests for copper and zinc were performed on D-shaped larvae and 6-month-old adults of both strains,calculating the median lethal concentration(LC_(50)).[Results]There were significant differences in copper and zinc contents between parental C.angulata of the two strains.During the D-shaped larval stage,the 24-hour zinc LC_(50) of larvae from the low accumulation strain was significantly lower than that of larvae from the high accumulation strain,while the 24-hour copper LC_(50) showed no significant difference between the two strains.Thus,the high accumulation strain exhibited significantly greater tolerance to zinc than the low accumulation strain,but both strains showed no significant difference in copper tolerance.In the adult stage,the copper and zinc LC_(50) values at 96 hours for adults of the high accumulation strain were higher than those of the low accumulation strain,indicating significantly greater tolerance to copper and zinc in the high accumulation strain compared to the low accumulation strain.[Conclusion]This study lays the groundwork for exploring the relationship between oyster metal accumulation capability and its tolerance,further providing insights into oyster metal accumulation and detoxification mechanisms.Additionally,research on oyster metal accumulation and tolerance phenomena is crucial for ensuring food safety and utilizing oysters as indicators for environmental monitoring.