Soil nitrogen and ozone effects on growth, physiology, and nutrition of loblolly pine and yellow-poplar seedlings

The effects of soil nitrogen level and chronic ozone (O /sub 3/) stress on carbon and nutrient economy were investigated in loblolly pine (Pinus taeda L.) and yellow-poplar (Liriodendron tulipifera L). The objectives of the study were: (1) to compare the growth and biomass partitioning in seedlings in response to varied low-nitrogen forest soil treatments in combination with chronic ozone levels over one growing season and (2) to investigate seedling physiological responses, including water use efficiency (WUE), photosynthesis, fine root and leaf nitrate reductase activity (NRA), nutrient concentration, nutrient uptake, and nutrient use efficiency (NUE). 135 refs., 12 figs., 16 tabs.