[Physiological responses of Gracilaria lemaneiformis to copper stress].
Gracilaria lemaneiformis was exposed to 0, 25, 50, 100, 250 and 500 microg x L(-1) of Cu2+ to study its physiological responses to Cu2+ stress. When the Cu2+ concentration was > or = 50 microg x L(-1), the relative growth rate (RGR) of G. lemaneiformis decreased significantly, and the optimal quantum yield (Fv/Fm), the maximum relative electron transfer rate (rETRmax), and the relative electron transfer efficiency (alpha) exhibited the same variation trend, compared with the control. With the increase of Cu2+ 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 Cu2+ concentration reached 500 microg x L(-1), the chlorophyll a, carotenoid, and phycobiliprotein contents decreased significantly. It was suggested that G. lemaneiformis could tolerate low concentration Cu2+ stress, but its physiological activities were inhibited markedly when exposed to > or =50 microg x L(-1) of Cu2+.
Institute of Marine Biology, Shantou University, Shantou 515063, Guangdong, China. 07xfzhu@stu.edu.cn
Xi-Feng
XF
Zhu
Ding-Hui
DH
Zou
Jian-Bo
JB
Jian
Wei-Zhou
WZ
Chen
Hui-Hui
HH
Liu
Hong
H
Du
D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003300:Copper / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D044724:Gracilaria / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D003300:Copper; D000077194:Chlorophyll A