南京林业大学学报（自然科学版）2025，Vol.49Issue(4)：37-45,9.DOI:10.12302/j.issn.1000-2006.202503037
大气臭氧浓度升高对美丽箬竹叶片叶绿素含量及光合特性的影响
Effects of elevated atmospheric O3 concentration on chlorophyll content and photosynthetic properties in new and old leaves of Indocalamus decorus
摘要
Abstract
[Objective]Rapid industrialization and urbanization under climate change have intensified atmospheric pollution across many regions of China.Ozone(O3),a phytotoxic secondary pollutant with increasing concentrations,has become a major summer time air pollutant in urban areas,posing serious threats to ecological security.Leaves of different ages may exhibit varying sensitivity or responses to atmospheric ozone(O3)pollution,and the physiological mechanisms underlying age-related differences in photosynthetic responses remain to be fully elucidated.This is crucial for a comprehensive understanding of the response mechanisms of bamboo species to atmospheric O3 pollution.This study investigated the effects of elevated O3 concentration(eO3)on the urban landscaping bamboo species Indocalamus decorus to assess whether leaf age influences the O3 resistance of I.decorus,and to elucidate the mechanistic links between chlorophyll fluorescence parameters and photosynthetic impairment.[Method]Nine open-top chambers(OTCs)were established with three O3 treatments in a suburban area of Changping District,Beijing.The OTCs,constructed with aluminum alloy frames and covered with 10 mm thick transparent plastic film(90％light transmittance),were 2.5 m in height and 2 m in diameter,with a ground area of 3.14 m2 and spaced 2 m apart.I.decorus,a small evergreen ornamental bamboo with significant economic value in China and broad applications as a sustainable"bamboo-as-plastic"substitute,was selected as the study species.It is commonly used in food packaging,temporary shelters,boat canopies,hat weaving,and textile manufacturing.Rhizomes of uniform age(five years),color,and thickness were selected,and 10 cm segments with consistent length and bud number were propagated.After one year,uniform seedlings were transplanted for the experiment.During the growing season,chlorophyll content,gas exchange,and chlorophyll fluorescence parameters were measured in both mature and newly emerged leaves.In view of rising O3 levels in Beijing and the known O3 tolerance of I.decorus,the O3 treatments included ambient air(AA),AA+70 ×10-9 O3(AA+70),and AA+140 ×10-9 O3(AA+140).O3 fumigation was conducted daily from 8:30 to 17:30(9 h),starting on June 1st and ending on October 12th.[Result](1)SPAD values of old and new leaves exhibited contrasting responses to O3.Under AA+70 and AA+140 treatments,SPAD values of old leaves decreased by 10.5％and 7.8％,respectively(P＜0.05),whereas SPAD values of new leaves increased by 6.3％under AA+140.A significant interaction between eO3 and leaf age was observed,with eO3 amplifying SPAD differences between leaf ages.(2)eO3 significantly reduced the maximum photosynthetic rate(Asat)and stomatal conductance(Gs)of older leaves under saturating light,but had no significant effects on younger leaves.The photosynthetic decline in older leaves was primarily attributed to non-stomatal limitations.(3)eO3 significantly decreased the actual quantum yield of PS Ⅱ(ΦPS Ⅱ),quantum efficiency of CO2 assimilation(PhiCO2),and electron transport rate(ETR)in both young and old leaves,with more pronounced reductions in older leaves.Additionally,eO3 reduced both photochemical quenching(qP)in young leaves.A significant interaction between eO3 and leaf age on PhiCO2 was observed,indicating that eO3 exacerbated the differences between young and old leaves.[Conclusion]Elevated O3 concentration induces chlorophyll degradation and PS Ⅱ photodamage in mature leaves,suppressing light reactions(reduced ΦPS Ⅱ)and electron transport(lowered ETR),thereby impairing photosynthesis.In contrast,new leaves exhibit compensatory mechanisms:preferential allocation of resources(e.g.,photoassimilates and antioxidants)helps stabilize chlorophyll content and maintain Asat,sustaining overall photosynthetic performance.This leaf-age-dependent resource allocation strategy-prioritizing younger leaves-enhances population-level O3 tolerance in I.decorus,underscoring its ecological adaptability and reinforcing its potential as a sustainable"bamboo-based plastic alternative".Future studies should investigate the long-term effects of O3 on chlorophyll fluorescence dynamics to better understand photosynthetic acclimation.This study provides precise data and theoretical support for understanding the impacts of air pollution on bamboo growth,offers a scientific foundation for the development of eco-friendly and sustainable bamboo industries,and contributes predictive insights into the effects of future climate change on urban green vegetation.关键词
大气O3浓度升高/美丽箬竹/光合荧光/叶绿素/叶片年龄效应Key words
elevated atmospheric O3 concentration/Indocalamus decorus/photosynthetic fluorescence/chlorophyll/leaf age effects分类
农业科技引用本文复制引用
李丽,张红星,李金玲,王效科,林树燕..大气臭氧浓度升高对美丽箬竹叶片叶绿素含量及光合特性的影响[J].南京林业大学学报（自然科学版）,2025,49(4):37-45,9.基金项目
生态环境部昆嵛山质量综合监测站开放课题(NIES-KYS-202401) （NIES-KYS-202401）
国家自然科学基金项目(031100028) （031100028）
江苏省"青蓝工程"优秀青年骨干教师培育项目(2022-40). （2022-40）
