水稻乳熟期功能叶光响应特性及模拟

The PAR Response Characteristics and Simulation of Rice Functional Leaves in Milky Stage

利用德国WALZ公司生产的GFS-3000便携式光合作用测量系统,在川香9838和辐优838两个水稻品种乳熟期分别测定了功能叶片在不同CO2浓度下的光合作用速率对光强的响应,并通过直角双曲和修正的直角双曲方程进行模拟,得到各模式的相关参数.结果表明,(1)在各个CO2浓度条件下,各功能叶片的光合作用速率不同,倒一叶净光合速率大于倒二叶,倒三叶最小;(2)在CO2浓度相同的情况下,随着光强的增加,光合作用速率呈增加的趋势,但在光合速率(PAR)到达1 000μmol/(m2.s)以上时,增加值逐渐减小,甚至不变化;(3)通过模拟,得到的初始量子效率α的值在0.013～0.052 5之间,低于理论值,α的值也受到CO2浓度的影响,CO2浓度低,α的值一般也偏低.

The response of photosynthetic rate（Pn） of the functional leaves of rice varieties Chuanxiang and Fuyou to light intensity（I） under different CO2 concentrations at the milky stage of the plants was measured with the GFS-3000 portable photosynthesis measurement system,and through simulation with the rectangular hyperbolic and the modified rectangular hyperbolic equations,the relevant parameters for the different models were obtained.Under different CO2 concentrations,the function leaves had different Pn values,the first leaf from the top having the highest Pn,followed in order by the second and the third leaves.Under the same CO2 concentration,Pn tended to increase with increasing I,and PAR（photosynthetic active radiation） reached the maximum at 1 000 μmol/（m2·s） and declined or remained stable thereafter.The simulated initial quantum efficiency α was in the range of 0.013-0.052 5,lower than the theoretical value.The value of α was influenced by CO2 concentration.With lower CO2 concentration,α tended to be low.