不同造林密度对油用柠檬桉光合特性的影响

Effects of Different Planting Densities on Photosynthetic Characteristics of Eucalyptus citriodora

分析在4个密度下[D1(0.7 m×0.8 m,17800株/hm 2)、D2(1.0 m×1.0 m,10000株/hm 2)、D3(1.0 m×1.5 m,6660株/hm 2)、D4(2.0 m×3.0 m,1650株/hm 2)]柠檬桉光合特性。结果表明:柠檬桉光饱和点为1636.56~1963.81μmol/(m 2·s),密度D3的光饱和点最高,D1的光饱和点最低;光补偿点为43.32~66.25μmol/(m 2·s),密度D3的光补偿点最高,D1的光补偿点最低;表观量子效率为0.0563~0.0689,不同密度间差异不显著;最大净光合速率为16.88~24.82μmol/(m 2·s),密度D3的最大净光合速率最高,D1的最大净光合速率最低;暗呼吸速率为1.63~2.56μmol/(m 2·s),密度D3的暗呼吸速率最高,D1的暗呼吸速率最低。密度D3最大净光合速率高,适应强光能力高,利用弱光能力低,表观量子效率高,暗呼吸速率高。

Photosynthetic characteristics of Eucalyptus citriodora under different planting densities,such as D1(0.7 m×0.8 m,17800 plants/hm 2),D2(1.0 m×1.0 m,10000 plants/hm 2),D3(1.0 m×1.5 m,6660 plants/hm 2)and D4(2.0 m×3.0 m,1650 plants/hm 2)were studied.The light saturation point of E.citriodora was 1636.56-1963.81μmol/(m 2·s).The light saturation point of density D3 was the highest among those four planting densities,while that of D1 was the lowest.The light compensation point of density D3 was 43.32-66.25μmol/(m 2·s).The light compensation point of density D3 was the highest,while that of D1 was the lowest.The apparent quantum efficiency of E.citriodora was 0.0563-0.0689,and the difference among different densities was not significant.The maximum net photosynthetic rate was 16.88-24.82μmol/(m 2·s),the maximum net photosynthetic rate of density D3 was the highest,and that of D1 was the lowest.Dark respiration rate was between 1.63-2.56μmol/(m 2·s),density D3 had the highest dark respiration rate and D1 had the lowest dark respiration rate.It was concluded that E.citriodora under D3 density had higher net photosynthetic rate,high adaptability to strong light,low utilization ability of weak light,and high apparent quantum efficiency,while E.citriodora under D3 density had low dark respiration rate.