三苯基氯化锡(TPTC)对孔石莼光合作用及生长的影响

EFFECTS OF TPTC ON PHOTOSYNTHESIS AND GROWTH OF MACROALGAE, ULVA PERTUSA

于 1 995年 5月在青岛太平角采集孔石莼 ,研究了三苯基氯化锡 (TPTC)对其光合、呼吸、色素含量及生长的影响。结果表明 ,低浓度的TPTC(≤ 2 μg/L)对光合过程无明显作用 ,高浓度的TPTC( >2 μg/L)能抑制光合作用 ,当TPTC浓度达到 1 6μg/L时 ,光合过程基本停止 ,TPTC对光合作用的半数效应浓度为 96hEC50 =7.39μg/L。低浓度的TPTC就能够使呼吸速率加快 ,但TPTC浓度达到 8μg/L后 ,呼吸速率开始下降。 1 μg/L的TPTC能促进叶绿素a的合成 ,当TPTC浓度在 2 μg/L以上时 ,叶绿素a含量下降 ,TPTC对叶绿素a含量的半数效应浓度为 96hEC50 =1 2 .99μg/L。TPTC能抑制藻片的生长 ,其对藻片半径增长和藻体生物量增加的半数效应浓度为 96hEC50 =4.0 1 μg/L和 1 0 .1 1 μg/L。

Macroalgae are important components of primary productivity in coastal areas. However, there is little knowledge about the toxic effects of organotin on macroalgae. In 1995, Ulva pertusa were collected from Taipingjiao, Qingdao study the toxic effects of Triphenyltin chloride (TPTC) on its photosynthesis, respiration, content of Chlorophyll- a and growth.\;TPTC showed no effects on photosynthesis process of Ulva pertusa until TPTC concentration reached 2μg/L, and the photosynthesis was almost totally inhibited at 16μg/L. The calculated value of 96h EC 50 for photosynthesis inhibition was 7.39μg/L. Respiration rate initially increased with low TPTC exposure level, and started to decrease from 8μg/L. But the respiration rate at 16μg/L was still higher than that of the control. Chlorophyll- a content was slightly higher than that of the control when TPTC concentration was 1μg/L, it decreased with TPTC level of 96h EC 50 =12.99μg/L. TPTC could inhibit the growth of Ulva pertusa both in size (96h EC 50 =4.01μg/L) and biomass (96h EC 50 =10.11μg/L).\;During the experiment, both respiration rate and content of Chlorophyll- a increased at low concentration of TPTC, which reflected a state of “physiological excitement”. This was probably due to the mechanism of self-protection of removing the pollutant. Compared to respiration process, which didn't show decreasing trend until 16μg/L, the photosynthesis process was more sensitive to TPTC. This might reflect the difference of sensitivity in chloroplast and mitochondria. Results show that the resistance of macroalgae to TPTC is 3—5 times higher than that of microalgae according to the toxicity data published before.