云南松与华山松人工混交林针叶光合速率对光及CO_2浓度的响应特征

Photosynthesis Rate in Response to Light Intensity and CO_2 Concentration in the Mixed Plantation of Pinus yunnanensis and Pinus armandii

采用Licor-6400型便携式光合作用测定系统测定了人工混交林中云南松、华山松光合作用对光、CO2浓度的响应曲线,阐述了云南松、华山松光合作用对光和CO2浓度的响应特征。结果表明:云南松、华山松光合速率随光强或CO2浓度的提高而增大,均可用非直角双曲线拟合,并得出一些光合响应特征参数,两树种间差异显著(P<0.05);云南松、华山松具有较高的光饱和点(LSP)和补偿点(LCP),表现为典型的喜阳性特点,具有较强的光能利用能力。在CO2饱和下,云南松、华山松最大净光合速率(Pm ax)分别可达14.768、10.289μmol.m-2.s-1,与光饱和下相比,最大净光合速率(Pm ax)分别提高了56.9%和62.0%。与华山松及几个北方针叶树相比,云南松具有较高的光饱和点、最大净光合速率、RuBP羧化效率(CE)、光呼吸速率(Rp)、CO2饱和点(CSP),以及较低的暗呼吸速率(Rd)、光补偿点、CO2补偿点(CCP)。云南松具有高光效和高CO2利用率等光合特性,属于高光能生产潜力的针叶树种。

The response of photosynthetic rate to light intensity and CO2 concenrtration in Pinus yunnanensis and P. armandii were measured with Licor-6400. The results indicated that these responses could be fitted by non-rectangle hyperbola equations. The characteristic parameters calculated from those equations were found to differ significantly between P. yunnanens/s and P. armandii. There were high light saturation point （LSP） and light compensation point（LCP） which were showed as typical heliophytes. It was indicated that the two coniferous trees had good adaptability of high photosynthetic active radiation （PAR） in southwest China; The maximum net photosynthetic rates of P. yunnanens/s and P. arrnandii could reach 14. 768 μmol · m^-2 · s^ -1 and 10. 289 μmol · m^ -2 · s^-1 respectively at the CO2 saturation point, and they were improved by 56.9% and 62.0% respectively at the light saturation point （LSP）. Compared with P. armandii and several northern coniferous trees, P. yunnanensis displayed higher light saturation point （LSP）, maximum net photosynthetic rate, earboxylation efficiency （CE）, photorespiration rate（Rp）, CO2 saturation point and lower dark respiration rate（Rd）, light compensation point and CO2 compensation point （CCP）. P. yunnanensis belongs to the high light energy potential productivity tree for its photosynthetic characteristics of high photosynthetic efficiency and high CO2 utilization ratio.