绣球对酸雨和铝复合处理的生长及铝吸收响应

Growth and aluminum absorption responses of Hydrangea macrophylla to combined treatments of acid rain and aluminum

为探究绣球在酸雨和铝(Al)复合胁迫下的生长及铝吸收响应特征,采用盆栽试验法,以绣球品种‘蓝色妈妈’为材料,研究模拟酸雨(pH 5.0和3.0)和铝(Al3+1和2 g/kg)复合处理下,绣球的生物量积累、光合色素含量、叶绿素荧光特性及铝积累与分配差异。结果表明:与对照组相比,单一酸雨处理下,绣球叶绿素含量和光系统Ⅱ(photosystemⅡ,PSⅡ)反应中心均无明显变化,弱酸(pH 5.0)处理显著增加了根、茎、叶及总生物量积累;单一铝处理下,铝质量分数为2 g/kg的处理组植株总生物量、叶绿素(a/b)值、光化学淬灭系数(qp)和电子传递速率(electron transport rate,ETR)均显著下降,非光化学淬灭系数(non-photochemical quenching coefficient,NPQ)显著上升。强酸高铝复合胁迫破坏了植物PSⅡ反应中心,造成光合色素含量降低,影响其组成,且抑制绣球的生长。单一铝、酸雨和铝复合处理均显著增加了植株叶及铝含量积累。在铝含量相同条件下,复合处理后的绣球铝积累量均高于单一铝处理,铝在植株各部位的积累量大小为根>茎>叶。模拟酸雨的强度和铝含量的交互作用对绣球NPQ、叶和总生物量及各部分铝含量有显著影响。综上所述,绣球具有较强的耐酸性,铝对绣球的影响作用大于酸雨,高铝强酸复合污染对绣球生长较为不利,酸雨促进了绣球对铝的吸收。

In order to investigate the growth and aluminum(Al)absorption responses of Hydrangea macrophylla under combined stress of simulated acid rain and Al,we studied biomass accumulation,photosynthetic pigment contents,chlorophyll fluorescence characteristics,and Al accumulation and distribution of‘Mama Blue’under different treatments[acid rain(pH 5.0 and 3.0),aluminum(Al3+1 and 2 g/kg)and their combinations]by pot experiments.The results showed that there were no significant effects on chlorophyll contents and photosystemⅡ(PSⅡ)reaction center under single acid rain treatment,and the biomass of root,stem,leaf and total biomass accumulation significantly increased under pH 5.0 treatment.Aluminum(2 g/kg)alone significantly decreased the total biomass,chlorophyll(a/b)value,photochemical quenching coefficient(qp)and electron transport rate(ETR),but the non-photochemical quenching coefficient(NPQ)was improved markedly.The low pH and high concentration of Al destroyed the PSⅡreaction center,reduced the photosynthetic pigment contents,affected its composition,and inhibited the growth of the plant.In addition,acid rain,Al stress and the compound treatment significantly increased the accumulation of leaves and total Al in the plants.Compared with Al stress alone,the total aluminum content under the compound pollution was higher at the same Al concentration.The accumulation of aluminum in different parts of the plant was as follows:root>stem>leaf.The interaction of acid rain and aluminum had significant impacts on NPQ,leaf and total biomass,and aluminum contents in various parts of the plant.In conclusion,H.macrophylla has strong acid resistance,and aluminum pollution affects them more than acid rain stress;acid rain promotes the absorption of aluminum,and the compound pollution of high aluminum and strong acid is disadvantageous to the growth of H.macrophylla.