臭氧胁迫对大豆根系形态和活性氧代谢的影响

利用开顶式气室(OTCs)对大豆进行臭氧(O3)胁迫试验,研究了高浓度O3对大豆根系体积、根瘤数、根瘤干重、根干重等根系形态指标以及膜脂过氧化程度、活性氧、抗氧化酶活性等活性氧代谢指标的影响.结果表明:在高浓度O3处理下,根系体积、根及根瘤干重、根瘤数降低,根系MDA含量、相对电导率显著上升,膜脂过氧化程度加剧;超氧阴离子(O2)产生速率和H2O2含量增加;O3胁迫处理的SOD活性在分枝期高于CK处理,其余各时期均低于CK处理;CAT活性除在开花期低于CK处理外,其它时期均高于CK处理;POD活性呈先升后降的趋势,各个时期均高于CK处理.高浓度O3导致大豆抗氧化系统的氧化损伤,对大豆表现为伤害效应,从而抑制了大豆根系的正常生长发育.

Effects of Ozone Stress on Root Morphology and Reactive Oxygen Species Metabolism in Soybean Roots

In recent years,the elevated ozone has become a serious problem which has some significant effects on plant.The response of morphological characteristics and reactive oxygen species metabolism in roots of soybean to elevated ozone concentrations was investigated in this paper.Soybean grown in open top chambers(OTCs)exposed to ambient air(O3=40 nL·L-1)and elevated ozone(O3=110±10 nL·L-1).Root volume,nodule number,root and nodule dry weight,relative electrical conductivity and malonaldehyde(MDA),hydrogen peroxide(H2O2)and superoxide anion(O-·2)production rate,activities of superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)were determined.The results showed that the root volume and root dry weight per plant decreased,then the nodule number and nodule dry weight per plant also declined with ozone concentration rising.Compared to CK,elevated ozone treatment significantly increased MDA and H2O2 content(P<0.05),relative electrical conductivity and O-·2 production rate(P<0.05).SOD activity was higher than CK at branching stage but lower than CK at the other stages under elevated ozone stress.Activity of CAT was lower than CK at flowering stage but higher at the other stages.Activity of POD increased in the early period and decreased in the late period,which was higher than CK at all growing stages.It can be concluded that the ozone stress has negative effects on soybean roots on account of oxidative damage,which restrains the growth and development of soybean roots.