红树植物秋茄幼苗对多环芳烃芘胁迫的生理生态响应

采用砂基栽培,研究不同浓度(0,0.1,1,10 mg/ L)多环芳烃芘(Pyr),对红树植物秋茄(Kandelia candel)幼苗光合色素含量、光合速率、可溶性糖和可溶性蛋白含量以及水分代谢的影响.结果表明: Pyr在0.1 mg/L及以下浓度,对秋茄幼苗叶片Chla、Chlb、叶绿素总量以及叶片的净光合速率的影响不明显;而浓度达1 mg/L及以上水平,则幼苗叶片Chla、Chlb和叶绿素总量均随之提高,Chla与Chlb比值未发生明显变化,而净光合速率则随之降低;Pyr浓度达1 mg/L及以上水平,对幼苗叶片的可溶性糖和可溶性蛋白含量,具有明显的促进作用.随着Pyr浓度的提高,幼苗原胚轴组织水势逐渐降低.Pyr浓度为0.1 mg/L,叶片气孔导度和蒸腾速率较对照组有明显提高,表现了PAHs的正刺激作用;浓度为1～10 mg/L,叶片气孔导度和蒸腾速率均显著降低.秋茄幼苗对环境Pyr胁迫的抗性适宜生长的浓度范围在0.1～1 mg/L之间.

Ecophysiological Responses of Mangrove Kandelia candel(L.)Druce Seedlings to Pyrene Stress

In this paper,the effects of increased concentrations of pyrene(0,0.1,1 and 10 mg/L) on the photosynthetic pigments,net photosynthetic rate,soluble sugar,soluble protein content,and water metabolism of mangrove Kandelia candel(L.) Druce seedlings were studied in sand culture.The results showed: the photosynthetic pigments and net photosynthetic rate of leaves showed no significant difference at concentration of 0.1mg/L pyrene.With increasing pyrene level,the photosynthetic pigments significantly increased at concentration of 1 mg/L pyrene and above,while the net photosynthetic rate significantly decreased.The ratio of chlorophyll a to chlorophyll b had no significant difference.Increasing pyrene concentrations (1 mg/L and above) induced an increase in the soluble sugar and soluble protein content of leaves.With increasing pyrene level,the water potential in hypocotyls decreased.The transpiration rate and stomatal conductance of seedlings at 1 mg/L were significantly higher than that of the control seedlings,whereas significantly decreased when at 1 and 10 mg/L pyrene.The tolerance range of pyrene in mangrove Kandelia candel(L.) Druce seedlings may be 0.1～1 mg/L.