向日葵对苯胺废水的光合生理响应及净化效果

摘要

为探讨向日葵对苯胺废水的耐受性及其应用于苯胺污染废水植物修复的可行性,采用水培试验方法,以美国油葵1号为材料,研究了不同苯胺浓度胁迫对向日葵光合和叶绿素荧光参数的影响,以及向日葵对苯胺的吸收、积累和净化效果.研究发现:100 mg/L的苯胺对向日葵的净光合速率(Pn)、气孔导度(Ls)和蒸腾速率(Tr)有显著的促进作用,而对生长与叶绿素荧光相关参数无显著的影响.当苯胺浓度升高到200-400 mg/L时,向日葵的鲜重、净光合速率(Pn)、实际光化学效率(ΦPSⅡ),最大光化学效率(Fv/Fm)以及光化学淬灭系数(qP)比对照组显著降低,而胞间CO2浓度(Ci)显著升高,NPQ呈现出先升高后降低的趋势,并在苯胺浓度为200 mg/L时达到最大值.综合分析表明,当苯胺浓度升高到200 mg/L到400 mg/L时,苯胺对向日葵的净光合速率的抑制以非气孔因素为主.当苯胺浓度为500 mg/L时,导致向日葵死亡.另外,向日葵对100 mg/L苯胺废水中苯胺的去除率最高,达到80.97％.苯胺主要在向日葵的地上部分积累,随着苯胺浓度的升高,向日葵中叶片苯胺的浓度逐渐升高,茎中的苯胺含量变化不显著,而根中的苯胺含量较低.%In order to investigate the tolerance of sunflower to aniline and the use of sunflower in the phytoremediation of aniline wastewater,we measured the effects of aniline stress on the photosynthesis and chlorophyll fluorescence parameters of hydroponic United States Oil Sunflower and the resulting contents of aniline in the wastewater and organs of sunflowers.At the low concentration of aniline (100 mg/L),the net photosynthesis rate,stomatal conductance,and transpiration rate of sunflower were significantly greater (P＜0.05) than that of the control.Meanwhile,fresh weight,the other photosynthesis parameters,and the chlorophyll fluorescence parameters were not significantly different.However,as the concentration of aniline increased,net fresh weight,net photosynthesis rate,maximum quantum yield of PSII,actual photochemical efficiency,and photochemical quenching were reduced,whereas non-photochemical quenching first increased,reaching a maximum at 200 mg/L and then decreasing thereafter.At the high concentration of aniline 500 mg/L,all the sunflowers died.The data indicated that non-stomatal limitation was responsible for the reduced net photosynthesis rate.Sunflower exhibited the greatest aniline removal rate (80.97％) at the low concentration of aniline (100 mg/L).The aniline was mainly accumulated in aboveground parts of the sunflower,and the content of aniline in the leaves increased along with the concentration of aniline in the wastewater.In contrast,the content of aniline in the stems was not significantly affected,and the content of aniline in the roots was low.