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基于叶片尺度的光强-光合响应测定,结合冠层CO2涡度通量观测,研究了长白山阔叶红松林主要树种及群落冠层的光合特征.结果表明,叶片及冠层光响应过程均可以用非直角双曲线模型很好地表达.蒙古栎具有较高的光补偿点Lcp(28μmol·m-2·s-1)、光饱和点Lsp(>1800μmol·m-2·s-1)及最大净光合速率Pmax(9.96μmol·m-1·s-1),表现为典型的喜阳性特点;色木槭的表观量子效率α(0.066)最大,Lcp(16μmol·m-2·s-1),Lsp(800μmol·m-2·s-1左右)及Pmax(4.51μmol·m-2·s-1)最低,表现为弱阳性特点;红松针叶的α值显著低于阔叶树,但具有较高的Pmax,表现为半喜阳特点.在冠层,α和Pmax都位于温带森林报导值的上限,而Lcp位于下限.冠层光合特征参数与叶片具有较好的一致性,均表现为相对较高的光合能力,但环境胁迫,特别是高的饱和水汽压差可显著降低叶片和冠层的光合能力.
Based on the leaf light intensity-photosynthesis response and the CO2 vorticity flux in the canopy, the photosynthetic characteristics of the dominant tree species and community canopy in broad-leaved Korean pine forests were studied. The results show that the light response of leaves and canopy can be well expressed by non-rectangular hyperbola model. Quercus mongolica had higher light compensation point Lcp (28μmol · m-2 · s-1), light saturation point Lsp (> 1800μmol · m-2 · s-1) and maximum net photosynthetic rate Pmax (9.96μmol · m -1 · s-1). The apparent quantum yield α (0.066) was the highest, Lcp (16μmol · m -2 · s -1), Lsp (800μmol · m -1) -2 · s-1) and Pmax (4.51μmol · m-2 · s-1), showing a weakly positive phenotype. The α value of the Korean pine needles was significantly lower than that of the broad-leaved trees but with a higher Pmax Half Xi Yang features. In the canopy, both α and Pmax are at the upper limit of temperate forest coverage, while Lcp is at the lower limit. The photosynthetic characteristics of canopy had good consistency with those of leaves, and all exhibited relatively high photosynthetic capacity. However, environmental stress, especially the high saturated vapor pressure difference, significantly reduced the photosynthetic capacity of leaves and canopy.