Characteristics of Water Physiology in Three Dominant Species of Mid-subtropical Forest
|School||Fujian Normal University|
|Keywords||Sap flow δ13C values Chinese fir Schima superba Castanopsis In the subtropical|
Application of thermal diffusion probe method and carbon stable isotope techniques three dominant tree species in the Nature Reserve of Fujian Wanmulin fir (Cunninghamia lanceolata), Schima (Schima superba), Castanopsis (Castanopsis fabri) measured sap flow characteristics value (sap flow velocities, SFV) and leaf carbon stable isotope composition (δ13C) value indicators, combined with automatic weather station synchronous continuous monitoring of solar radiation, air temperature, relative humidity and other environmental factors, the three dominant tree species in the water physiological The characteristic conduct research, explore the mechanism of coniferous and deciduous tree in subtropical evergreen broad-leaved forest ecosystem to adapt to the environment. The study results show that: (1) the overall trend of the season three dominant tree species in the trunk flow daily process is different. Among them, the fir trunk unit area of ??the liquid flow rate of the average and peak from the non-growing season to growing season rising fluctuations in flow rate of the average range of 0.65 ± 0.82 cm · h-1 ~~ 2.40 ± 2.94cm · h-1 peak fluctuations 1.55cm · h-1 ~ 8.10cm · h-1; Schima superba and Castanopsis is increased at first and then a downward trend, the performance of the average fluctuation range for the Schima trunk unit area of ??the liquid flow rate of 3.50 ± 4.56cm · h-1 ~ -8.09 ± 9.69cm · h-1; peak fluctuations 12.20cm · h-1 ~ 25.45cm · h-1; of Castanopsis trunk unit area average liquid flow rate fluctuation range of 3.41 ± 3.57cm · h-1 ~ 7.11 ± 7.39 cm-h-1; peak fluctuation amplitude 13.32 cm · h-1 ~ 19.35cm, the h-1. In the day, the three dominant tree species growing season sap flow start time is earlier than the non-growing season, flow duration than non-growing season long. Both in the non-growing season or growing season, the two broadleaf Schima Castanopsis trunk unit area of ??the liquid flow rate is much larger than the average and peak conifer fir. Size (2) sunny conditions, the three dominant tree species is influenced by environmental factors: vapor pressure deficit gt; air relative humidity gt; solar radiation gt; air temperature; cloudy conditions, with the exception Castanopsis solar radiation is most sensitive In addition, fir and Schima by air relative humidity affect the maximum air temperature of three species of the weakest; rainy conditions, the three dominant tree species affected by environmental factors are basically the same, the water vapor pressure deficit of the three dominant species the greatest impact, the influence of solar radiation is the weakest. (3) two broadleaf Schima and Castanopsis leaves δ13C (wooden Dutch -30.85 ‰ Castanopsis -32.55 ‰) were lower than conifers fir (-29.46 ‰), but the transpiration rate than conifers fir high performance Schima superba The Castanopsis sap per unit area of ??the liquid flow rate of the average fir 6-fold and 5-fold. Sunshine, adequate water habitats, due to the lower WUE and higher transpiration rate of water use strategies decided Schima superba and Castanopsis faster growth rate, the two broadleaf competitive advantage was significantly greater than conifers fir. The study results suggest that the water physiological characteristics in subtropical coniferous and deciduous tree water physiological ecology and ecological adaptation to specific habitats and coniferous and deciduous tree species between differences in subtropical evergreen broad-leaved forest Physiology and Ecology Research provides theoretical and practical reference.