臭氧浓度升高对坪用高羊茅生长、亚细胞结构及活性氧代谢的影响

Effects of increased O_3 concentration on growth,subcellular structure and reactive oxygen metabolism of turf-type Festuca arundinace

通过开顶箱(OTCs)模拟,以环境臭氧(O_3)浓度约40 nmol·mol^(-1)为对照,研究大气O_3浓度升高(80和160 nmol·mol^(-1)O_3)对冷季型草坪草高羊茅生长、亚细胞结构及其活性氧代谢的影响.结果表明:14 d的80 nmol·mol^(-1)O_3熏蒸使高羊茅株高和叶宽降低,总生物量降低43.7%,老叶变黄,而160 nmol·mol^(-1)O_3处理高羊茅叶出现大量枯死褐斑,叶尖坏死,新叶卷曲,总生物量降低46.2%,叶肉细胞膜卷曲,叶绿体和线粒体受损严重.与对照相比,80和160 nmol·mol^(-1)O_3熏蒸下高羊茅叶片超氧阴离子(O2-·)产生速率、过氧化氢(H2O2)和丙二醛(MDA)含量显著增加,抗氧化酶活性显著升高,但叶片总酚含量和抗氧化能力随O_3浓度升高而先升高后降低.在明显O_3伤害症状出现之前,O_3已对高羊茅的生长和抗氧化代谢产生不利影响;高羊茅抗氧化系统虽对O_3浓度的升高存在一定的适应性反应,但其不能抵御过高浓度的长期胁迫和伤害.

Taking ambient environmental O3（40 nmol·mol^-1） as control,the study was conducted to assess the impact of elevated O3（80 and 160 nmol·mol^-1） on the growth,subcellular structure and reactive oxygen metabolism of turf-type Festuca arundinace in open top-chambers（OTCs）.The results showed that under 14-day fumigation,the height and leaf width of F.arundinace decreased significantly,and the total biomass decreased by 43.7%,and some fully expanded leaves yellowed under 80 nmol·mol^-1 O3.Some visible injury symptoms,brown spots and necrosis appeared in the leaves,the total biomass decreased by 46.2%,and plasma membrane became loose from the cell wall and convoluted,chloroplast and mitochondria were damaged under 160 nmol·mol^-1 O3.The rate of superoxide anion（O2-·） production,hydrogen peroxide（H2 O2） content,malonaldehyde（MDA） content and the activities of antioxidant enzymes were higher under the increasing O3 concentrations（80 and 160 nmol·mol^-1） compared with control.Total phenolics and the antioxidant capacity increased at first and then decreased with the rise of O3 concentration.It indicated that O3 has already affected F.arundinace growth and antioxidative metabolism before visible injury symptom appeared.F.arundinace had an adaptive response to elevated O3,but it could not protect itself from excessive O3 or long-term O3 exposure.