摘要
近地层臭氧(O_(3))浓度升高对植物的不良影响随着暴露时间的延长如何变化?国内外研究还很少.选取樱桃萝卜(Raphanus sativus var.radculus)为对象,采用开顶式气室(OTC),设置4个O_(3)熏蒸浓度(NF:环境O_(3)浓度;NF40:NF+40 nmol/mol;NF80:NF+80 nmol/mol;NF120:NF+120 nmol/mol),通过建立O_(3)暴露剂量AOT40与各指标的剂量响应关系模型,研究O_(3)浓度升高和暴露时间延长对樱桃萝卜生长发育和生理生化指标的响应及变化规律.结果表明:(1)随着暴露时间的延长,高浓度O_(3)熏蒸下叶片褪绿和黄化程度加重.O_(3)浓度升高,受害叶片占比增大,叶面积减小.(2)O_(3)浓度升高,樱桃萝卜叶片内叶绿素(Chl)、类胡萝卜素(Car)及可溶性蛋白(SP)含量显著降低(P<0.01),丙二醛(MDA)、可溶性糖(SS)、还原型抗坏血酸(ASC)、还原型谷胱甘肽(GSH)含量和总抗氧化能力(T-AOC)显著升高(P<0.001).随着暴露时间的延长,樱桃萝卜叶片内Chl、Car、MDA、SS、SP、ASC和GSH含量对O_(3)污染的敏感性会出现减弱,而T-AOC敏感性会出现增强,表明随着O_(3)胁迫时间的延长,植物会产生适应性.(3)樱桃萝卜肉质根体积和肉质根、茎、叶、细根生物量随着O_(3)暴露剂量AOT40的增大显著下降(P<0.05).NF40、NF80和NF120处理组肉质根生物量与NF相比分别降低了18.06%、46.29%、67.11%.樱桃萝卜肉质根、细根和茎生物量对O_(3)胁迫的敏感性都在后期达到最大值,叶生物量敏感性先减弱后增强.表明随着O_(3)暴露时间延长,O_(3)对植物生物量的影响会加剧.(4)O_(3)浓度升高,樱桃萝卜肉质根中Ca、Mg含量下降,而K、Fe含量增加.综上所述,长时间高O_(3)熏蒸降低了樱桃萝卜的光合作用,提高了抗氧化能力,最终导致生物量降低,影响了肉质根的营养品质.同时植株产生了适应;研究可为认识植物对O_(3)胁迫的长期响应和适应机制及科学估算O_(3)对植物的危害程度提供重要参考.
How do the adverse effects of elevated near-ground ozone(O_(3))concentrations on plants vary with exposure time?Few studies have been conducted at home and abroad.In this study,Raphanus sativus var.radculus was selected using an open-top chamber and four O_(3)concentration levels(NF:environmental O_(3)concentration;NF40:NF+40 nmol/mol;NF80:NF+80 nmol/mol;NF120:NF+120 nmol/mol).By establishing a dose-response relationship model between the O_(3)exposure dose AOT40 and each index,the response and change rule of the growth and physiology of Raphanus sativus var.radculus leaves with increasing O_(3)concentration and prolonged exposure time were studied.The results indicated that(1)with the extension of exposure time,the degree of chlorosis and yellowing of leaves under high concentration of O_(3)fumigation continued to increase.With an increase in O_(3)concentration,the proportion of damaged leaves increased and leaf area decreased.(2)Chlorophyll(Chl),carotenoid(Car),and soluble protein(SP)contents in Raphanus sativus var.radculus leaves decreased significantly with increasing O_(3)concentration(P<0.01),and the contents of malondialdehyde(MDA),soluble sugar(SS),ascorbic acid(ASC),glutathione(GSH),and total antioxidant capacity(T-AOC)increased significantly(P<0.001).With the extension of exposure time,the sensitivity of chlorophyll,carotenoid,MDA,SS,SP,ASC,and GSH contents in Raphanus sativus var.radculus leaves to O_(3)pollution decreased,whereas the sensitivity of T-AOC was enhanced,indicating that with the extension of O_(3)stress time,plants will have adaptability.(3)The size of the hypocotyl and the biomass of the hypocotyl,stem,leaves,and fiber root of Raphanus sativus var.radculus decreased significantly after exposure to AOT40(P<0.05).Compared with NF,the biomass of the hypocotyl in the NF40,NF80,and NF120 treatment groups decreased by 18.06%,46.29%,and 67.11%,respectively.The sensitivity of the hypocotyl,fiber root,and stem biomasses in Raphanus sativus var.radculus to O_(3)stress reached a maximum at a later stage,and the sensitivity of the leaf biomass increased at a later stage.This indicated that the effect of O_(3)on plant biomass was aggravated by an increase in O_(3)exposure time.(4)With an increase in the O_(3)concentration,the Ca and Mg contents in the hypocotyls of Raphanus sativus var.radculus decreased,whereas K and Fe contents increased.In conclusion,long-term fumigation with high O_(3)reduced photosynthesis in Raphanus sativus var.radculus improved antioxidant capacity and led to a reduction in biomass,thereby affecting the nutritional quality of the hypocotyl.Simultaneously,the plants adapted.This study provides an important reference for understanding the long-term response and adaptation mechanisms of plants to O_(3)stress and for scientifically estimating the degree of damage caused by O_(3)to plants.
作者
冯美琪
耿春梅
王效科
高艺芹
张丹红
殷宝辉
张楠
宋蕊
刘颖
万五星
FENG Meiqi;GENG Chunmei;WANG Xiaoke;GAO Yiqin;ZHANG Danhong;YIN Baohui;ZHANG Nan;SONG Rui;LIU Ying;WAN Wuxing(College of Life Sciences,Hebei Normal University,Shijiazhuang 050024,China;Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Chinese Research Academy of Environmental Sciences,Beijing 100012,China)
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2023年第6期1364-1372,共9页
Chinese Journal of Applied and Environmental Biology
基金
国家大气污染防治攻关联合中心项目(DQGG2021202)
国家自然科学基金项目(31971509)
河北省自然科学基金项目(C2017205152)资助
关键词
O_(3)
樱桃萝卜
可见伤害
生理指标
生物量
O_(3)
Raphanus sativus var.radculus
visible injury symptom
physiological index
biomass