Comparative gas-exchange in leaves of intact and clipped, natural and planted cherrybark oak (Quercus pagoda Raf.) seedlings

Abstract

Gas-exchange measurements, including C0₂2-exchange rate (net photosynthesis), stomatal conductance, and transpiration, were conducted on intact and clipped cherrybark oak (Quercus pagoda Raf.) seedlings growing in the field and in a nursery bed. Seedlings in the field, released from midstory and understory woody competition, showed significant increases in gas-exchange compared to non-released seedlings due to increases in light levels reaching seedlings. Concurrently, little difference occurred in the C0₂-exchange rate between intact and clipped seedlings in the released treatment although clipped seedlings maintained a consistently greater rate of stomatal conductance. In order to reduce the high variability of light levels recorded in the field, gas-exchange measurements were conducted on intact and clipped cherrybark oak seedlings growing in a nursery bed under consistent light conditions. Again, no differences were found in the C0₂-exchange rate between intact and clipped seedlings. Furthermore, no differences were found in stomatal conductance and transpiration between intact and clipped seedlings. However, significant differences in gas-exchange were found between first-flush and second-flush leaves regardless of seedling treatment (intact or a sprout). Greater rates of gas-exchange in second-flush leaves can be attributed to developing third-flush steams and leaves.

Citation

Lockhart, Brian R.; Hodges, John D. 2005. Comparative gas-exchange in leaves of intact and clipped, natural and planted cherrybark oak (Quercus pagoda Raf.) seedlings. In: Proceedings Arkansas Academy of Science, Vol. 48: 104-110