This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were s...This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates （ETRmax） were measured as rapid light curves （RLCs） by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 ~C. Non- photochemical quenching （NPQ） of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield （Fv/Fm） of submerged marestail in Five Colored Lake showed full recovery at 170o h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highestin Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant＇s ecophysiological reactions.展开更多
Located in southwestern China, Jiuzhaigou National Park is one of the most popular tourism destinations in China, famous for its unique aquatic ecosystems and beautiful forests. However, plants in the park may be at h...Located in southwestern China, Jiuzhaigou National Park is one of the most popular tourism destinations in China, famous for its unique aquatic ecosystems and beautiful forests. However, plants in the park may be at high ozone risk as a result of the intensive use of diesel tour buses in the park. In addition, Jiuzhaigou is close to a region with relatively high regional anthropogenic NOn emissions. During the growing season, also the peak season of tourism, we measured ozone concentration at two sites within the Park and these were： Jiuzhaigou Bureau （JB） and Long Lake （LL）. The results indicate that ozone concentrations were not high enough to cause foliar injury during the monitoring period, although the risk of ozone to plants was higher in spring than in summer and autumn. Diurnal ozone cycles at JB and LL displayed significantly higher ozone concentrations in the daytime than in the nighttime, suggesting photochemical production of ozone during the day and ozone deposition during the night as a result of the nocturnal boundary layer. In parallel with the seasonal change of background surface ozone in the Northern Hemisphere, maximum daily 8-h average ozone concentration （MDA8） and daily ozone concentration decreased from spring to autumn at the two sites. This temporal variation in Jiuzhaigou wasmost likely associated with the downward mixing of ozone-rich air from the free troposphere, because all the high-ozone events （MDA8 〉 70.0 ppb） were observed in spring and ozone-rich air from the free troposphere was the dominant cause. In summary, our data suggest that ozone concentrations in Jiuzhaigou were more affected by the regional-scale of background pattern in air quality and meteorological conditions than by local tourist activities.展开更多
基金funded by the International Program of the Ministry of Science and Technology of China (2010DFA91280)111 Project(B08037)
文摘This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates （ETRmax） were measured as rapid light curves （RLCs） by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 ~C. Non- photochemical quenching （NPQ） of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield （Fv/Fm） of submerged marestail in Five Colored Lake showed full recovery at 170o h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highestin Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant＇s ecophysiological reactions.
基金funded by the International Program of the Ministry of Science and Technology of China (2010DFA91280) 111 Project(B08037)
文摘Located in southwestern China, Jiuzhaigou National Park is one of the most popular tourism destinations in China, famous for its unique aquatic ecosystems and beautiful forests. However, plants in the park may be at high ozone risk as a result of the intensive use of diesel tour buses in the park. In addition, Jiuzhaigou is close to a region with relatively high regional anthropogenic NOn emissions. During the growing season, also the peak season of tourism, we measured ozone concentration at two sites within the Park and these were： Jiuzhaigou Bureau （JB） and Long Lake （LL）. The results indicate that ozone concentrations were not high enough to cause foliar injury during the monitoring period, although the risk of ozone to plants was higher in spring than in summer and autumn. Diurnal ozone cycles at JB and LL displayed significantly higher ozone concentrations in the daytime than in the nighttime, suggesting photochemical production of ozone during the day and ozone deposition during the night as a result of the nocturnal boundary layer. In parallel with the seasonal change of background surface ozone in the Northern Hemisphere, maximum daily 8-h average ozone concentration （MDA8） and daily ozone concentration decreased from spring to autumn at the two sites. This temporal variation in Jiuzhaigou wasmost likely associated with the downward mixing of ozone-rich air from the free troposphere, because all the high-ozone events （MDA8 〉 70.0 ppb） were observed in spring and ozone-rich air from the free troposphere was the dominant cause. In summary, our data suggest that ozone concentrations in Jiuzhaigou were more affected by the regional-scale of background pattern in air quality and meteorological conditions than by local tourist activities.
