3种模型对毛竹快速生长期冠层叶片叶绿素荧光—快速光响应曲线(RLC_S)拟合的比较

为定量研究亚热带经济竹种毛竹(Phyllostachys edulis)在大小年快速生长期的叶绿素荧光特性及其光响应规律.以2龄竹、4龄竹和6龄竹的3个竹龄毛竹为材料,采用便携式调制式叶绿素荧光仪测定各竹龄毛竹出笋前期(4月)冠层叶片叶绿素荧光快速响应曲线(RLC_S),应用直角双曲线修正模型、双指数方程、非直角双曲线模型拟合,计算对应参数,筛选出最佳的光合响应曲线拟合模型,并进一步测定拟合整个快速生长期(4-7月)3个竹龄的快速响应曲线参数变化.结果表明:直角双曲线修正模型在最大电子(J_(max))、饱和光强(PAR_(sat))、初始斜率(α)及拟合系数(R~2)均优于传统双指数方程和非直角双曲线模型,为拟合毛竹叶绿素荧光快速响应曲线(RLC_S)最优模型;毛竹叶片光合机制大小年差异显著,大年与小年的光合高峰分别出现在6月和5月,快速生长期内的光合响应能力总体表现为Ⅱ度竹Ⅰ度竹Ⅲ度竹.因此,建议在竹林经营中,应集中在大小年光合高峰期间追施肥料,并且注意维持各竹龄的适当立竹结构,以促进毛竹林整体可持续发展.

The comparison of three models of Phyllostachys edulis in canopy during the fast growth period fitting with PSⅡ chlorophyll fluorescence rapid light curves ( RLCS ) method

To study the chlorophyll fluorescence characteristics of moso banmboo ( Phyllostachys edulis) quantitatively and its light response mechanism, moso bamboo at different growth stages, including 2, 4, 6 years old, was measured by portable fluorescence measurement system at early shooting stage in April. Then rapid light curves ( RLCS ) based on previous figure were matched by modified rectangular hyperbolic model, nonrectangular hyperbolic model and ambiexponent equation to screen the optimum model. The results showed that modified rectangular hyperbolic model was the optimum model in terms of maximum rate of photosynthetic elactron transport ( Jmax ) , saturation intensity ( PARsat ) and coefficient of determination ( R2 ) . Photosynthetic mechanism of bamboo varied significantly between on-year and off-year, with the maximum photosynthesis rate being in June for on-year and in May for off-year. General photosynthetic response ability in rapid growth period in a descending order were degreeⅡ, degreeⅠ, and degreeⅢ. We suggest fertilization during the peaks of photosynthesis in on-year and off-year respectively, and maintaining a sustainable struc-ture of bamboo at different ages.