模拟酸雨对桉树苗木生长及生理的影响

摘要

采用盆栽法,研究4个不同pH(3.0、4.0、5.0、5.6)的模拟酸雨对巨尾桉9号苗木叶片苗高、地径、生物量、叶绿素含量、细胞膜透性、丙二醛含量、抗氧化物酶活性的影响.以探讨不同pH的模拟酸雨对桉树苗木生长及生理的影响.研究结果表明,随着模拟酸雨pH值的降低,巨尾桉9号苗木苗高相对生长量及地径相对生长量总体呈下降趋势,且分别在pH 3.0、pH 4.0时达到最小;不同pH的酸雨处理下,生物量变化不明显;叶绿素a、叶绿素b、叶绿素总含量及叶绿素a/b、相对电导率、丙二醛含量随着酸雨pH值的降低总体呈上升趋势,在pH 3.0时,达到最大;随着模拟酸雨的pH的降低,巨尾桉9号叶片内超氧化物歧化酶、过氧化氢酶活性呈先上升再下降趋势,均在pH4.0时达到最高,过氧化物酶活性随着模拟酸雨pH值的降低逐渐上升;苗高相对生长量与相对电导率、丙二醛含量间存在显著负相关关系;地径相对生长量与相对电导率间呈显著负相关.轻度模拟酸雨可促进巨尾桉9号生物量及叶绿素含量的积累,pH4.0时,其相对电导率和丙二醛含量均显著高于对照,多种抗氧化酶活性达到最高,模拟酸雨对细胞膜产生了一定伤害,但对其生长影响不明显,说明巨尾桉9号对酸雨具有较强的抵抗能力.%In pot experiments,we studied the effect of simulated acid rain including 4 different pH levels (3.0,4.0,5.0,5.6) on the height,ground diameter,biomass,chlorophyll content,cell membrane permeability,MDA content and antioxidant enzyme activities of E.grandis × E.urophylla No.9 seedlings leaves.With the decrease of PH value in simulated acid rain,the downward trend was observed in height and ground diameter relative growth rate,with the lowest value in pH 3.0 and pH 4.0 in E.grandis × E.urophylla No.9 seedlings;the biomass did not change significantly under different simulated acid rain.Chlorophyll a (b,a/b),total chlorophyll content,relative conductivity and MDA content increased with pH decreasing in simulated acid rain,the maximum was at pH 3.0;The superoxide dismutase and catalase activity in the leaves of E.grandis × E.urophylla No.9 seedlings increased first and then decreased,reaching the maximum at pH 4.0,and peroxidase activity gradually increase with the decrease of pH in simulated acid rain;There was significant negative correlation observed among relative growth of seedling height,relative conductivity and MDA content,the same correlation was also observed between ground diameter and relative conductivity.Mild simulated acid rain can promote biomass and chlorophyll content in E.grandis × E.urophylla No.9 seedlings,both the relative conductivity and MDA content were significantly higher than that in control,a variety of antioxidant enzyme activity reached maximum,simulated acid rain damaged the cell membrane,whereas the effect was not obvious on growth,which indicating that a strong resistance to acid rain in E.grandis × E.urophylla No.9 seedlings.