苯酚废水对垂柳叶片光合生理参数的影响

为探讨垂柳(Salix babylonica)对苯酚污染物的耐受程度及其应用于苯酚污染环境修复的可行性,了解苯酚胁迫对垂柳光合作用生理过程的影响与限制机理,采用水培模拟胁迫实验方法,在5种苯酚溶液浓度(50、100、200、400和800mg·L–1)下,测定垂柳植株叶片光合气体交换及叶绿素荧光参数。结果表明,苯酚对垂柳光合作用具有显著的抑制作用,表现为叶片净光合速率(Pn)、最大光合速率(Pnmax)、光合量子效率(Φ)、PSII最大和实际光化学效率(Fv/Fm和ФPSII)等均明显下降。苯酚胁迫浓度越高,对垂柳光合作用的抑制程度越大;苯酚胁迫限制光合作用主要由非气孔因素引起。将垂柳用于苯酚污染的水体环境修复时,苯酚浓度应在200 mg·L–1以下,否则垂柳的光合作用效能会明显降低。垂柳光合作用生理活性耐受苯酚胁迫的极限浓度还需进一步实验研究。

The Effect of Phenol Concentration on Photosynthetic Physiological Parameters of Salix babylonica

To explore the phenol tolerance of Salix babylonica and the feasibility of its remediation of phenol pollution, we determined the effect of phenol stress on photosynthetic physiology of S. babylonica and its limit mechanism, photosynthesis and chlorophyll fluorescence parameters of cut seedlings of S. babylonica in five phenol concentrations (50, 100, 200, 400 and 800 mg·L^-1) using hydroponics. Phenol inhibited the photosynthesis of S. babylonica significantly, which presented as significantly decreased net photosynthesis rate (P_n), maximum net photosynthesis rate (P_nmax), photosynthetic quantum efficiency, maximum quantum yield of PS II (F_v/F_m) and actual photochemical efficiency (Ф_PSII). The higher the concentration of phenol, the greater the photosynthetic inhibition. Non-stomatal limitation was responsible for reduced net photosynthesis rate (P_n). When S. babylonica was used to phytoremediate the water environment, the concentration of phenol should be < 200 mg·L^-1. Otherwise the efficiency of photosynthesis of S. babylonica was markedly decreased. The limit of phenol concentration that photosynthetic physiological activity of S. babylonica can tolerate needs further experimental study.