大气中O3、CO2浓度升高对蒙古栎叶片生长的影响

以4年生蒙古栎(Quercus mongolica) 幼树为实验材料,分别于2007,2008年6~9月采用开顶箱法,研究了高浓度CO2和O3及复合作用对蒙古栎叶片光合量变化和生长的影响.结果表明,高浓度O3处理下蒙古栎叶片日光合总量降低, 单叶鲜重、干重和单叶面积均有所下降,对蒙古栎叶片生长产生抑制.高浓度CO2处理下,蒙古栎叶片干、鲜重和单叶面积均高于对照,其中2007年差异显著,日光合总量总体高于对照.2种气体复合作用处理下,蒙古栎日光合总量、单叶鲜重、单叶干重、单叶面积均低于对照,且高于O3单独处理,说明高浓度CO2可以通过减缓O3对植物光合的抑制,进而减少O3伤害,缓解生长抑制.

Effects of elevated O3 or/and CO2 on growth in leaves of Quercus mongolica

To study the responses of photosynthesis and growth in leaves of Quercus mongolica to elevated O3, elevated CO2 and elevated O3+CO2 in urban area, experiment was conducted in Shenyang Arboretum located at the center of the city. Four-year-old trees grown in open-top chambers (OTC) were exposed to control, elevated O3, elevated CO2 and elevated O3 + elevated CO2 for two growing seasons, and the growth (fresh weight, dry weight, leaf, area per leaf ), and diurnal assimilation amounts of Quercus mongolica leaves were measured. Diurnal assimilation amounts were decreased in elevated O3 treatment, the fresh weight, dry weight and area per leaf were also reduced by elevated O3 compared to the control. Under elevated CO2 exposure, the fresh weight, dry weight and area per leaf were increased, significantly in 2007, While, Diurnal assimilation amounts were increased after elevated CO2 exposure in total. When trees were exposed to both elevated O3 and elevated CO2, the fresh weight, dry weight, area per leaf and Diurnal assimilation amounts were all lower than control but higher than only elevated O3 treatment, which indicated that high CO2 can largely relieve the damage of high O3 to photosynthesis of Quercus mongolica leaves, so as to relieve the O3-induced negative effect of leaves growth.