tUrban green spaces (UGS) offer several ecosystemical benefits to the urban environment. However, theseadvantages may be weakened by alterations of plants photophysiological mechanisms due to increasingtropospheric ozone (O3) concentrations, a serious problem for China. To evaluate their utilization in UGS,we selected three widely-used urban plant species (smoke tree, Cotinus coggygria Scop.; marigold, Tageteserecta Linn.; rose, Rosa chinensis Jacp.) to investigate their biometric and photophysiological responsesto (i) ambient air (AA), (ii) AA + 60 ppb O3(AA + 60), and (iii) AA + 120 ppb O3(AA + 120) (9 h d−1, from8:30 am to 5:30 pm). Considering visible injury and biomass production, smoke tree and marigold seemto be O3-sensitive, whereas rose should be considered more tolerant. The exposure to the pollutant gasreduced photosynthetic efficiency in all seedlings. However, different features were shown throughoutour study by the three species here monitored. In smoke tree, stomatal limitations seemed to be itsprincipal weakness. In marigold, the reduction of the photosynthetic performance was mainly ascribableto impairments of both light and dark reactions of photosynthesis. Here, stomatal closure maybe not thecause to limit the photosynthetic rate, but a down-regulated response. Unexpectedly, CO2assimilationincreased in roses exposed to AA + 60 and did not change in those treated with AA + 120 after one monthfrom the beginning of the exposure (FBE). This seemed due to a better efficacy of these plants in darkreactions of photosynthesis. This feature was confirmed also a month later. In conclusion, the resultsof this study indicate that non-invasive methods such as gas exchange and chlorophyll fluorescence formonitoring photosynthetic performance of urban plants can be useful to give guidelines to manage UGSin the “climate change era”. Generally, in severe O3-polluted areas as those of several cities of China,the plants with high-efficient biochemical processes driving a well photosynthetic performance (such asrose) might be a recommended choice.
Ozone effects on photosynthesis of ornamental species suitable forurban green spaces of China
Lorenzo Cotrozzi;
2016-01-01
Abstract
tUrban green spaces (UGS) offer several ecosystemical benefits to the urban environment. However, theseadvantages may be weakened by alterations of plants photophysiological mechanisms due to increasingtropospheric ozone (O3) concentrations, a serious problem for China. To evaluate their utilization in UGS,we selected three widely-used urban plant species (smoke tree, Cotinus coggygria Scop.; marigold, Tageteserecta Linn.; rose, Rosa chinensis Jacp.) to investigate their biometric and photophysiological responsesto (i) ambient air (AA), (ii) AA + 60 ppb O3(AA + 60), and (iii) AA + 120 ppb O3(AA + 120) (9 h d−1, from8:30 am to 5:30 pm). Considering visible injury and biomass production, smoke tree and marigold seemto be O3-sensitive, whereas rose should be considered more tolerant. The exposure to the pollutant gasreduced photosynthetic efficiency in all seedlings. However, different features were shown throughoutour study by the three species here monitored. In smoke tree, stomatal limitations seemed to be itsprincipal weakness. In marigold, the reduction of the photosynthetic performance was mainly ascribableto impairments of both light and dark reactions of photosynthesis. Here, stomatal closure maybe not thecause to limit the photosynthetic rate, but a down-regulated response. Unexpectedly, CO2assimilationincreased in roses exposed to AA + 60 and did not change in those treated with AA + 120 after one monthfrom the beginning of the exposure (FBE). This seemed due to a better efficacy of these plants in darkreactions of photosynthesis. This feature was confirmed also a month later. In conclusion, the resultsof this study indicate that non-invasive methods such as gas exchange and chlorophyll fluorescence formonitoring photosynthetic performance of urban plants can be useful to give guidelines to manage UGSin the “climate change era”. Generally, in severe O3-polluted areas as those of several cities of China,the plants with high-efficient biochemical processes driving a well photosynthetic performance (such asrose) might be a recommended choice.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
