青藏高原3种主要植被类型的表观量子效率和最大光合速率的比较

The Comparative Study of the Apparent Quantum Yield and Maximum Photosynthesis Rates of 3 Typical Vegetation Types on Qinghai-Tibetan Plateau

以海北高寒草甸生态系统定位站的涡度相关系统连续观测的CO2通量数据为基础,分析了青藏高原的高寒矮嵩草(Kobresia humilis)草甸、高寒金露梅(Potentilla fruticosa)灌丛草甸和高寒藏嵩草(Kobresia tibetica)沼泽化草甸等3种主要植被类型在2005年植物生长季(6-9月)的表观量子产额(a)、最大光合速率(Pmax)和呼吸速率(Reco)的变化特征。结果表明:3种植被类型白天的净生态系统CO2交换量(NEE)和光量子通量密度(PPFD)存在明显的直角双曲线关系(P<0.05),其a、Pmax和Reco呈现出相似的季节变化趋势,在生长季初期(6月)最小,在7月或8月份达到最大;高寒矮嵩草草甸的a、Pmax和Reco大于灌丛草甸和沼泽化草甸,而后两者差别不大。

Based on the continuous CO2 flux data monitored by Eddy Covariance Method at Haibei Station, the variations of apparent quantum yield（α）, maximum photosynthesis rate （Pmax）, and ecosystem respiration rate （Reco） were analyzed for three vegetation types （alpine Kobresia humilis （C. A. Mey） Serg. meadow, alpine Potentilla fruticosa L. shrubland, and alpine K. tibetica Maxim. wetland） in growing season （from June to September） on the Qinghai-Tibetan Plateau. The results show that the daytime net ecosystem exchange （NEE） fitted very well with Photosynthetic photon flux density （PPFD） in a rectangular hyperbola equation in three types of vegetation ecosystems. Their α, Pmax, and Reco showed the similar seasonal changing pattern, the minimum was appeared in June and maximum in July or August; the α, Pmax and Reco of the alpine K. humilis meadow was higher than that of the other two vegetation types and no significant differences of α, Pmax, and Reco between alpine P. fruticosa shrubland and alpine K. tibetica wetland were detected.