Characteristics of photosynthesis and respiration in Fraxinus rhynchophylla Hance and Fraxinus mandshurica Rupr. leaves
1989
Han, S.S. | Sim, J.S. (Kangweon National Univ., Chunchon (Korea R.). Coll. of Forestry)
The present study was to examine the effects of light, temperature, and water stress on the photosynthesis and respiration rates and its seasonal changes in 3-year-old Fraxinus rhynchophylla and Fraxinus mandshurica seedlings raised in pot in nursery. The estimated light compensation points at which net photosynthesis approached zero were 35 and 28 micro E m** (-2) s** (-1) for F. rhynchophylla and F. mandshurica leaves, respectively. The light saturation points occurred at 700 micro E m** (-2) s** (-1) in these species. The maximum rates of net photosynthesis of leaves occurred at about 25deg C in F. rhynchophylla and at 20deg C in F. mandshurica. The decrease in net photosynthetic rates of leaves began at -13 bars in F. rhynchophylla and -10 bars in F. mandshurica, and then its rates approached approximately zero at -23 bars in F.mandshurica and -29 bars in F. rhynchophylla. The dark respiration rates of leaves were similar from 10deg C to 40deg C between these species. Also these increased from -10 bars to -28 bars, and then decreased remarkably in these species. The net photosynthetic rates of leaves of F. mandshurica were higher than those of F. rhynchophylla until June, and after that lower than F. rhynchophylla. The dark respiration rates of leaves of F. rhynchophylla were higher than those of F. mandshurica from June to August, and after that similar between these species. The respiration rates of stem and root were highest in April during the growing season. These values of F. rhynchophylla ere slightly higher than those of F. mandshurica throughout the growing season
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