NO_(2)胁迫对三角梅幼苗生理特性的影响

Effects of NO_(2) stress on physiological characteristics of Bougainvillea glabra seedlings

【目的】本研究旨在分析园林植物对城市道路环境中典型污染物NO2气体的响应特征,为深入探究城市大气污染环境下园林植物适应大气NO2污染的机制提供理论依据。【方法】采用智能化人工熏气装置,设置3种NO2浓度(CK 0μL·L^(-1),T1 1μL·L^(-1),T2 4μL·L^(-1),T3 8μL·L^(-1)),研究不同NO2浓度下三角梅形态指标(叶片Lab植)、水分生理(相对含水量RWC、水分饱和亏缺WSD)、逆境生理(丙二醛MDA、脯氨酸Pro、可溶性蛋白含量SP、超氧化物歧化酶SOD、还原型抗坏血酸AsA)、光合生理(叶绿素a、叶绿素b、类胡萝卜素)的响应特性。【结果】1)短期高浓度NO2胁迫下,三角梅叶片的Lab值具有一定程度的变化,但对叶片颜色的影响不显著;2)与CK相比,T1和T2的RWC均呈先增加后降低的趋势,T3处理下的RWC持续升高,WSD均呈现相反的变化趋势;3)各处理组在胁迫期间,MDA含量与CK相比整体呈现下降的趋势;T1及T2的AsA含量均呈现先增加后降低的趋势,T3处理的AsA含量逐渐增加;Pro及SP含量变化规律不明显,随着胁迫程度的增加,三角梅Pro含量总体呈先上升后下降的趋势,而SP含量总体呈下降趋势;各处理组的SOD活性与CK基本持平,组间差异不显著;4)T1和T2处理对三角梅光合色素含量具有一定的促进作用,其中T2处理的促进作用更明显;5)利用相关性分析及主成分分析法发现,叶绿素a、b含量及类胡萝卜素含量可作为三角梅响应短期高浓度NO_(2)胁迫的主要指标,主要反映三角梅的光合能力,WSD和SP可作为辅助指标,主要反映三角梅的水分利用能力及渗透调节能力。【结论】三角梅可通过调控自身光合能力、水分利用能力及渗透调节能力等耐受短期(3 d)高浓度(8μL·L^(-1))NO_(2)急性胁迫。

【Objective】This study aims to analyze the response characteristics of garden plants to NO_(2),a typical pollutant in the urban road environment,and provide the theoretical basis for further exploring the mechanism of garden plants adaptation to atmospheric NO_(2) pollution in urban air pollution environment.【Method】Intelligent artificial fumigation device was used to set three concentrations of NO_(2)(CK 0μL·L^(-1),T11μL·L^(-1),T24μL·L^(-1),T38μL·L^(-1)).The morphological indexes(leaf Lab value),water physiology(relative water content RWC,water saturation deficit WSD),stress physiology(MDA,Pro,SP,SOD,AsA),photosynthetic physiology(chlorophyll a,chlorophyll b,and carotenoid)of Bougainvillea glabra under different NO_(2) concentrations were studied response properties.【Result】1)The Lab value of B.glabra leaves changed to a certain extent under short-term high concentrations of NO_(2) stress,but the effect on leaf color was not significant;2)Compared with CK,RWC of T1 and T2 both showed a trend of first increase and then decrease,RWC of T3 treatment continued to increase,and WSD showed an opposite trend;3)During the stress period,MDA content in all treatment groups showed a downward trend compared with CK.AsA content in T1 and T2 increased first and then decreased,and AsA content in T3 increased gradually.The change in Pro and SP contents was not obvious.With the increase in stress degree,the Pro content of B.glabra showed a trend of first increasing and then decreasing,while the SP content showed a trend of decreasing.The SOD activity of all treatment groups was the same as that of CK,but the difference between groups was not significant;4)T1 and T2 treatments had a certain promoting effect on the content of the photosynthetic pigment in B.glabra,and T2 treatment had a more significant promoting effect;5)The results of correlation analysis and principal component analysis showed that the chlorophyll content of a,b and carotenoid content could be used as B.glabra primary indicators of short-term high concentration of NO_(2) stress response and mainly reflected B.glabra photosynthetic capacity,WSD and SP could be used as an auxiliary index,mainly reflected water use and osmotic adjustment ability of B.glabra.【Conclusion】B.glabra could tolerate short-term(3 d)high concentration(8μL·L^(-1))NO_(2) acute stress by regulating photosynthetic capacity,water use capacity,and osmotic regulation capacity.