[Gas exchange features of Ambrosia artemisiifolia leaves and fruits and their correlations with soil heavy metals].
Ambrosia artemisiifolia can survive well in the habitats of heavy human disturbance and partial soil pollution. Weather its photosynthetic features benefit their survival is worthwhile to concern. With a refuse dump in Changchun City (43 degrees 50'N, 125 degrees 23'E) as study site, this paper analyzed the contents of soil Cu, Pb, Zn, Mn, Cr, Co, Ni, Cd, As, Sb and Hg at ten plots, and measured in situ the gas exchange in A. artemisiifolia leaves and young fruits. The results showed that the study site was slightly contaminated by Ni, but the contents of other soil heavy metals were approached to or substantially lower than their threshold values. The net photosynthetic rate of leaves ranged from 1.88 to 9.41 micromol x m(-2) x s(-1), while that of young fruits could be up to 2. 81 micromol x m(-2) s(-1). Averagely, the respiration rate, stomatal conductance, photosynthetic rate, and water utilization efficiency of leaves were 1.81 micromol x m(-2) x s(-1), 75.7 mmol x m(-2) x s(-1), 6.05 micromol x m(-2) x s(-1), and 4.72 micromol CO2 x mmol(-1) H2O, being 5.26, 0.64, 1.31 and 1.69 times as much as those of young fruits, respectively, indicating that the respiratory and photosynthetic capacities and water use efficiency of A. artemisiifolia young fruits were equivalent to or higher than those of its leaves. Many test heavy metals, such as Cu, Pb, Zn, Cd, As, Sb and Hg, had no significant effects on the gas exchange features of leaves and fruits, but there were significant correlations of Ni and Cr with the stomatal conductance and water use efficiency of leaves and young fruits, Cr with the gross photosynthesis of leaves, and As with the stomatal conductance of young fruits, suggesting that a majority of test soil heavy metals had no direct effects on the gas exchange in A. artemisiifolia leaves and fruits, but soil Ni, Cr and As with the contents approached to or substantially lower than the threshold values could affect the gas exchange features of A. artemisiifolia.
Zu
Yuangang
Y
Key Laboratory of Forest Plant Ecology of Education Ministry, Northeast Forestry University, Harbin 150040, China. zygorl@vip.hl.cn
Wang
Wenjie
W
Chen
Huafeng
H
Yang
Fengjian
F
Zhang
Zhonghua
Z
D031164:Ambrosia / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D005638:Fruit / Q000378:metabolism*; D019216:Metals, Heavy / Q000032:analysis*; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000378:metabolism; D018526:Plant Transpiration / Q000502:physiology; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis
D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D002245:Carbon Dioxide