铜镍单一及复合胁迫对柳叶马鞭草光合和叶绿素荧光的影响

Effects of photosynthetic characteristics and chlorophyll fluorescence in Verbena bonariensis under single and combined Cu and Ni stress

摘要:

【目的】 揭示柳叶马鞭草幼苗对铜、镍单一及复合胁迫的适应能力。【方法】 采用沙培盆栽法， 以柳叶马鞭草为试验材料，测定不同铜浓度（0、300、600、900、1 500 mg/kg）、镍浓度（0、300、600、900、1 500 mg/kg）、铜镍复合浓度（0、300、600、900、1 500 mg/kg）处理下柳叶马鞭草幼苗光合、荧光参数及叶绿素含量。【结果】 随铜、镍单一及复合胁迫程度增加，株高、叶长、叶宽、叶面积、根系活力、叶绿素和类胡萝卜素均先升后降，并在Cu.300、Ni.300、Cu+Ni.300时达到最大；蒸腾速率、净光合速率、气孔导度、水分利用效率、气孔限制值均降低，并在Cu.1500、Ni.1500、Cu+Ni.1500时降至最小；胞间CO₂ 浓度持续升高，表明非气孔因素限制了光合作用；除非光化学淬灭系数上升外，其余荧光参数（潜在光化学活性、最大光化学效率、光合电子传递速率、光化学淬灭系数和光化学量子产量）均降低；根、茎、叶中 Cu²⁺、Ni²⁺含量显著增加，且根＞叶＞茎，当Cu.1500、Ni.1500、Cu+Ni.1500时，根系Cu²⁺、Ni²⁺含量分别为2 461.27、1 506.21、2 080.14 mg/kg（Cu²⁺）和1 469.45 mg/kg（Ni²⁺）。【结论】 柳叶马鞭草对铜、镍单一及复合胁迫有较强的耐受性，且吸收与积累的Cu²⁺、Ni²⁺多在根部。

Abstract:

【Objective】 To reveal the adaptability of Verbena bonariensis under single and combined Cu and Ni stress.【Method】 Verbena bonariensis was cultured in river sand with nutrient solution，and leaf photosynthetic characteristics and chlorophyll fluorescence indexes were determined by setting different copper （or Cu） stress concentrations of 0，300，600，900，and 1 500 mg/kg，different nickel （or Ni） stress concentrations of 0，300，600，900，and 1 500 mg/kg，and different combined Cu and Ni stress concentrations of 0，300，600，900，and 1 500 mg/kg，respectively.【Result】 With increasing single and combined Cu and Ni stress，plant height，leaf length，leaf width，leaf area， root activity，chlorophyll，and carotenoid contents increased first and then decreased and reached the maximum value at Cu. 300，Ni. 300，and Cu+Ni. 300，respectively. Transpiration rate，net photosynthetic rate，stomatal conductance， water use efficiency，and stomatal limitation value were decreased and reached the minimum value at Cu. 1500， Ni. 1500，and Cu+Ni. 1500，respectively，while intercellular carbon dioxide concentration increased and reached the maximum value at Cu. 1500，Ni. 1500，and Cu+Ni. 1500，respectively，which indicated that the non-stomatal factor restricted photosynthesis. Except for the increase of the non-photochemical quenching coefficient，actual photochemical efficiency，maximum photochemical efficiency，electron transport rate，photochemical quenching coefficient，and photochemical quantum yield were decreased. The contents of Cu²⁺ and Ni²⁺ in roots，stems，and leaves increased significantly and the order was roots ＞ leaves ＞ stems. Cu²⁺ content in roots was 2 461. 27 mg/kg at Cu. 1500，and Ni²⁺ content in roots was 1 506. 21 mg/kg at Ni. 1500，and Cu²⁺ and Ni²⁺contents in roots were 2 080. 14 mg/kg and 1 469. 45 mg/kg at Cu+Ni. 1500，respectively.【Conclusion】Verbena bonariensis has strong tolerance under single and combined Cu and Ni stress，and the contents of Cu²⁺ and Ni²⁺ are mostly in the roots.