中文摘要：

研究了大型海藻龙须菜（Gracilaria lemaneiformis）对不同浓度重金属铜（0、25、50、100、250和500μg·L^-1）胁迫的生理响应.结果表明：当Cu^2＋浓度≥50μg·L-1时,龙须菜藻体的相对生长速率显著下降,最大光化学量子产量、最大相对电子传递速率和相对电子传递效率呈相同的变化趋势.随着Cu^2＋浓度的升高,龙须菜藻体最大净光合速率和光饱和点显著降低,而光补偿点显著升高,叶绿素a、类胡萝卜素和藻胆蛋白含量则呈先升高后下降的趋势;当Cu^2＋浓度达到500μg·L^-1时,叶绿素a、类胡萝卜素和藻胆蛋白含量显著下降.说明龙须菜在低浓度Cu^2＋胁迫下具有一定的抵抗能力,而当Cu2＋浓度≥50μg·L^-1时,会对藻体生理活动造成显著的抑制作用.

英文摘要：

Gracilaria lemaneiforrnis was exposed to 0, 25, 50, 100,250 and 500 μg·L-1 of Cu^2＋ to study its physiological responses to Cu^2＋ stress. When the Cu^2＋ concentration was 250 μg·L-1, the relative growth rate （RGR） of G. lemaneiforrnis decreased significantly, and the optimal quantum yield （Fv/Fm ） , the maximum relative electron transfer rate （rETR ）, and the relative electron transfer efficiency （α） exhibited the same variation trend, compared with the control. With the increase of Cu^2 ＋ concentration, the maximum net photosynthetic rate （Pmax） and light saturation point （LSP） decreased significantly, light compensation point （LCP） had a significant increase, while chlorophyll a, carotenoid, and phycobiliprotein contents decreased after an initial increase. When the Cu^2＋ concentration reached 500μg · L^-1, the chlorophyll a, carotenoid, and phyeobiliprotein contents decreased significantlv. It was suggested that G. lemaneiformis could tolerate low concentration Cu^2＋ stress, but its physiological activities were inhibited markedly when exposed to ≥50μg ·L^-1 of Cu^2＋.