高级检索

对流层臭氧影响植物叶片光合速率的荟萃分析

A Meta-Analysis of the Response of Leaf Photosynthesis Rate to Tropospheric Ozone

  • 摘要: 对流层臭氧(O3)作为一种重要的大气污染物,对全球植物生长发育构成威胁,其导致的生态胁迫不仅严重阻碍了碳中和目标的实现,而且还给粮食安全带来不可忽视的挑战。光合作用是关键的植物生理过程,也是大气中的碳元素进入陆地生态系统的途径。以往关于O3污染影响植物光合速率的定量研究大多仅限于1或2种植被类型、单一环境交互因子、或较短时段的分析。本研究收集整理了过去52年(1970年1月至2022年12月)公开发表,且经过严格质量控制后的1263条O3熏蒸实验观测数据,通过荟萃分析(Meta-analysis)方法,全面地分析了植物光合速率对O3的响应,揭示了植被类型、臭氧浓度(O3)、O3和其他环境因子复合作用、以及树木年龄对该响应的影响。结果表明O3升高可使植物光合速率显著降低22.29%。不同植被类型的光合速率对O3的响应不同,农作物、灌木和阔叶树最敏感,光合速率分别降低了25.82%、23.28%和22.14%,而草和针叶树响应较小,分别降低14.51%和6.70%。阔叶树和针叶树的光合速率随O3升高先增大后减小,而农作物的光合速率随O3的升高先减小后增大。对于O3与不同天气气候和环境因子的复合作用,干旱、霜冻、增加CO2、施肥、同时增加CO2和施氮肥均可减轻O3对植物的伤害,而当O3 ≥70 ppb(ppb=10−9)时,遮荫和高盐分土壤则会增加O3的负面影响。此外,树木叶片光合速率对O3的响应随着树木年龄的增长而增强,尤其是针叶树。我们的研究结果将为全球变化背景下O3污染影响陆地植物生理生态和陆地生态系统碳收支提供重要参考。

     

    Abstract: Tropospheric ozone (O3), as one of the primary atmospheric pollutants, poses a global threat to plants, causing ecological stress that severely hinders the achievement of carbon neutrality goals and significantly endangers food security. Photosynthesis is a critical physiological process and a pathway for carbon to enter terrestrial ecosystems. Previously, studies focused only on one or two vegetation types, a single environmental interaction factor, or over a short period. This study compiled 1263 observations from O3 fumigation experiments published over the past 52 years (from January 1970 to December 2022) and conducted strict data quality control. Through meta-analysis, a comprehensive analysis was conducted on the response of the plant photosynthesis rate to O3, revealing the impact of the vegetation type, ozone concentration (O3), combined effects of O3 with other environmental factors, and tree age on this response. Our meta-analysis results show that elevated O3 significantly reduces the plant photosynthesis rate by up to 22.29%. The response of photosynthesis rates to the O3 variation across vegetation types is as follows. Crops, shrubs, and broadleaf trees are the most sensitive, with photosynthetic rate reductions of 25.82%, 23.28%, and 22.14%, while grass and needle-leaf trees have smaller responses, decreasing by 14.51% and 6.70%, respectively. The tree photosynthesis rates increase and then decrease with rising O3, while for crops, the rate falls first and then rises. As for the combined effects of O3 with different environmental factors, drought, frost, elevated CO2 concentration (CO2), fertilization, and the simultaneous increase of CO2 and fertilization can alleviate O3 stress, while shading and high soil salinity will exacerbate O3 stress when O3 ≥ 70 ppb. Furthermore, the photosynthetic rate of tree leaves in response to O3 intensifies with the increasing age of trees, particularly in the case of needle-leaf trees. Our findings provide an important reference for understanding the influence of O3 pollution on the plant physiological process and carbon cycle of terrestrial ecosystems in the context of global change.

     

/

返回文章
返回