黄土丘陵区铁杆蒿光合蒸腾特性的研究

Photosynthetic and Transpiration Characteristics of Artemisia gmelinii in the Loess Hilly Region

使用Li-6400便携式光合测定仪,测定了自然条件下黄土丘陵区铁杆蒿的光合速率、蒸腾速率和光合响应等指标。结果表明:(1)晴天叶片净光合速率在12点达到峰值21.19μmolCO2.m-2.s-1,日变化为平稳的单峰曲线。(2)铁杆蒿的光补偿点为44.1μmol.m-2.s-1,光饱和点为351μmol.m-2.s-1,说明铁杆蒿喜光但不属于典型的阳生植物。(3)铁杆蒿的蒸腾速率(Tr)随有效光辐射强度(PAR)的增强一直处于上升趋势,没有出现蒸腾速率饱和现象。(4)铁杆蒿叶片水分利用效率(WUE)随PAR的增强呈抛物线状变化,<160μmol.m-2.s-1时,WUE增加较快,当PAR在160-2000μmol.m-2.s-1内变化时,WUE基本维持在2.5-3.39 mmol.mol-1之间。

Photosynthetic rate, transpiration rate and photosynthetic response of Arternisia grnelinii were measured in the field using the Li-6400 portable photosynthesis system in loess plateau hilly region. The results showed that the diurnal variation of net photosynthetic rate （Pn） was a smooth one-peak curve in sunny day. The peak of photosynthetic rate appeared at 21.19μmolco2· m^-2· s^-1. The light compensation point （LCP） and the light saturation point （LSP） of Artemisia grnelinii were 44. 1μmol · m^-2 · s^-1 and 351μmol · m^-2 · s^-1 ,respectively. This indicated that Arternisia grnelinii was a sunny plant and not a typical sun plant. With increasing PAR, transpiration rate was increasing along and had no saturation peak. The water use efficiency （WUE） of Artemisia grnelinii abided with a parabola model while increasing PAR. when PAR was less than 160μmol · m^-2 · s^-1 , it increased greatly, when PAR varied from 160 to 2000μmol · m^-2 · s^-1, WUE changed from 2.5 to 3.39 mmol · mol^-1.