查看文章

We studied the effects of elevated ozone ([O₃]) and CO₂ concentrations ([CO₂]) on the growth and photosynthesis of the hybrid larch F₁ (F₁) and on its parents (the Dahurian larch and Japanese larch). F₁ is a promising species for timber production in northeast Asia. Seedlings of the three species were grown in 16 open top chambers and were exposed to two levels of O₃ (<10 ppb and 60 ppb for 7 h per day) in combination with two levels of CO₂ (ambient and 600 ppm for daytime) over an entire growing season. Ozone reduced the growth as measured by height and diameter, and reduced the needle dry mass and net photosynthetic rate of F₁, but had almost no effect on the Dahurian larch or Japanese larch. There was a significant increase in whole-plant dry mass induced by elevated [CO₂] in F₁ but not in the other two species. Photosynthetic acclimation to elevated [CO₂] was observed in all species. The net …