• 关键词：紫叶李  SO₂  光合色素  花青苷  荧光参数

• 基金项目：国家林业局“948”项目(No.2001-40);河北农业大学科学研究基金项目

• 李彦慧
• 河北农业大学, 保定 071000

• 孟庆瑞
• 河北农业大学, 保定 071000

• 李向应
• 乌兰察布职业学院生物技术系, 集宁 012000

• 李保国
• 河北农业大学, 保定 071000

• 杨建民
• 河北农业大学, 保定 071000

• 摘要：以盆栽紫叶李的2年生嫁接苗为试材,采用人工静态熏气装置分析了不同浓度SO₂(0～22.8mg·m^-3)胁迫条件下(16d)紫叶李叶片光合色素含量及荧光动力学参数的变化情况.研究结果显示:在SO₂浓度为5.7mg·m^-3的胁迫下,叶绿素a(Chla)、叶绿素b(Chlb)、Chla/Chlb、总叶绿素和类胡萝卜素(Car)含量均比对照增加,在其它浓度处理下均减小,且与对照间差异显著(11.4mg·m^-3胁迫下叶绿素a和类胡萝卜素除外).在SO₂浓度小于11.4mg·m^-3时,紫叶李叶片花青苷和类黄酮含量随着胁迫强度的增强而增加(与对照间差异显著,p<0.01);而在SO₂浓度大于11.4mg·m^-3时则随着胁迫强度的增强而降低(与对照间差异显著,p<0.01).荧光动力学参数中,PSⅡ原初光能转化效率F_v/F_m随着胁迫强度的增强呈现先增加后降低的变化趋势,PSⅡ潜在活性F_v/F_o、光化学淬灭效率q_P随着胁迫强度的增强而减小,而荧光非光化学淬灭效率q_N却随着胁迫强度的增强而增加.研究结果表明,紫叶李苗木在低浓度SO₂(小于11.4mg·m^-3)胁迫下通过自身较强的保护系统使机体免受伤害;而在高浓度SO₂(大于11.4mg·m^-3)胁迫下通过增加q_N耗散过剩的光能和提高ΦPSⅡ消耗多余能量来保护光合器官免受损伤,但叶片的光合色素含量和其它荧光参数均受到不同程度的影响,紫叶李叶片受到伤害与PSⅡ反应中心失活有关.

• Abstract：Two-year-old pot-planted seedlings of Prunus cerasifera var.atropurea were studied to determine the effect of SO₂ stress on photosynthetic pigments,anthocyanin and chlorophyll fluorescence parameters.Under SO₂ treatment in a closed chamber at a rate of 5.7 mg·m^-3,the contents of chlorophyll a,chlorophyll b,chlorophyll a+chlorophyll b,carotenoid increased,but the differences were not significant compared with the control.However for higher levels of SO₂,these parameters decreased significantly compared with the control(except chlorophyll a and carotenoid under 11.4 mg·m^-3 SO₂ stress).As the stress increased,the content of anthocyanin and flavonoids increased at SO₂ concentrations below 11.4 mg·m^-3,and decreased significantly at concentrations higher than 11.4 mg·m^-3.Considering the chlorophyll fluorescence parameters,F_v/F_m first increased and then decreased as the SO₂ concentration increased,while q_N increased at greater SO₂ concentrations.F_v/F_o and q_P decreased accordingly with the increase of SO₂ concentration.We conclude that Prunus cerasifera var.atropurea could protect itself from damage through a highly active protection system under low SO₂ concentrations(lower than_11.4 mg·m^-3),while under higher SO₂ concentrations(higher than 11.4 mg·m^-3)the protection mechanism could protect the photosynthetic apparatus from damage resulting from surplus light energy through increasing q_N and ΦPSⅡ,but the photosynthetic pigments and the other chlorophyll fluorescence parameters were negatively affected.The results demonstrate that damage to the leaves of Prunus cerasifera var.atropurea is related to the inactivation of the PSⅡ reaction center.

• Key words：Prunus cerasifera var.atropurea  SO₂ stress  photosynthetic pigments  anthocyanin  chlorophyll fluorescence parameters

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