毛竹对大气臭氧胁迫的生理响应变化

以毛竹1年生盆栽苗为材料,运用开顶式气室(OTCs)模拟环境背景大气O3浓度(AA,40～45 nL·L-1)和高O3浓度(EO,92～106 nL·L-1)情景,分析毛竹叶片光合生理、脂质过氧化及抗氧化酶等主要生理指标的变化,为气候变化背景下的竹林培育应对策略提供理论依据.结果显示:(1)EO较AA在同一处理时间的毛竹叶片O3通量均显著升高,且二处理的叶片O3通量均随着处理时间的延长呈升高趋势.(2) EO较AA的光合速率(Pn)、气孔导度(Gs)和可溶性糖含量均显著下降,且叶片叶绿素(ChD含量、胞间CO2浓度(Ci)显著下降的时间点分别出现在EO处理的60 d和92 d,可溶性蛋白在处理60 d后显著升高;随处理时间的延长,EO的叶片Pn、Ci、Chl含量均呈下降趋势,可溶性糖和可溶性蛋白含量呈先升高后降低的趋势;Pn下降由气孔限制因素引起.(3)超氧自由基(O2)含量、丙二醛(MDA)含量、相对电导率分别在处理29 d、60 d、60 d后均显著升高,且随着处理时间的延长呈升高趋势.(4)超氧化物歧化酶(SOD)活性在高浓度O3处理60 d时显著升高,后显著下降,而POD活性均显著升高,且SOD和POD活性均随着处理时间呈先升高后降低的趋势.研究表明,毛竹对大气高O3胁迫存在着短时间的主动生理生化适应,但长期高O3胁迫会对毛竹造成严重的过氧化伤害,从而影响毛竹的正常生长.

Changes of Physiological Responses of Phyllostachys edulis to Atmospheric Ozone Stress

To provide theoretical evidence to aid adaptive management of bamboo plantations operating under the background of climate change,we studied the effects of simulated increased atmospheric ozone concentrations on photosynthesis,lipid peroxidation and anti-oxidation enzymes in the leaves of Phyllostachys edulis (moso bamboo).The open-top chamber (OTC) test method was employed in conjunction with a split-plot design and ozone concentrations set to AA(40~45 nL·L^-1) and EO(92~106 nL·L^-1).The results showed that:(1)Compared with AA,ozone flux increased significantly in the leaves of Ph.edulis at the same treated time under EO;Ozone flux increased with the extension ozone exposure under AA and EO treatments.(2)Photosynthetic rate(P_n) and stomatal conductance(G_s) and soluble sugar content decreased significantly in the same treated time under EO,and chlorophyll(Chl) content and intercellular CO² concentration (C_i) decreased significantly in the treatment time of 60 d and 92 d respectively,while soluble protein content increased significantly after 60 d;With elongated ozone exposure,photosynthetic rate(P_n),intercellular CO₂ concentration(C_i),chlorophyll(Chl) content and soluble protein content decreased in the leaves of Ph.edulis,and soluble sugar content increased and then decreased.And we concluded the decline in P_n resulted from the stomatal conductance limitation.(3)Superoxide radical(O^-·₂) content and malondialdehyde (MDA) content and relative electrical conductivity increased significantly after the treatment time of 29 d,60 d and 60 d,respectively and shown a rising trend with the extension of processing time.(4)The activity of super oxide dismutase(SOD) increased significantly in the initial 60 days of ozone treatment,then decreased significantly and peroxidase activity(POD) increased significantly;The activities of SOD and POD increased and then decreased.The result illustrated that Ph.edulis responded in acclimation way in the initial O₃ fumigation period;but in the late period,the growth of Ph.edulis would be affected seriously.