3种金鸡菊的光合特性比较

以3种金鸡菊属Coreopsis植物1年生扦插苗为研究对象，在室外自然条件下，运用美国产的Li－6400光合系统测定仪对其光合作用日变化和光响应进行了测定。结果表明：3种金鸡菊的光补偿点和光饱和点各不相同。对光的适应范围大小为重瓣金鸡菊Coreopsis fanceolata〉大花金鸡菊Coreopsis grandiflora〉天堂之门金鸡菊Coreopsis rosea；对强光的利用能力大小为重瓣金鸡菊〉天堂之门金鸡菊〉大花金鸡菊。3种金鸡菊属植物的净光合速率（Pn）日变化都呈双峰型曲线。第l峰值均大于第2峰值，有明显的光合午休现象，蒸腾速率（r）和气孔导度（G训）变化趋势与净光合速率相似。胞间二氧化碳摩尔分数（Ci）变化趋势则与其相反。3种金鸡菊属植物的水分利用效率（EwuE）差异显著，大小依次为大花金鸡菊〉重瓣金鸡菊〉天堂之门金鸡菊。图4表1参24

Photosynthetic characteristics of three Coreopsis species

To determine diurnal variation of photosynthetic Coreopsis grandiflora, Coreopsis lanceolata, and Coreopsis was used under natural light conditions. Results indicated characteristics and light intensity responses for rosea an Li-6400 photosynthetic system analyzer different light compensation and light saturation points. The light adaptive range sequence was C. lanceolata 〉 C. grandiflora 〉 C. rosea, and the ability to use relatively strong light was C. lanceolata 〉 C. rosea 〉 C. grandiflora. In addition, diurnal variation in the net photosynthetic rate （P,） for all three species displayed double-peaked curves with a greater initial peak and a clear photosynthetic noon break. Compared to Po, the transpiration rate （Tr） and stomatal conductance （Co~d） showed similar changes; however, changes in intercellular carbon dioxide concentration （Ci） were reversed. Al- so, water use efficiency （EwuE） for the three Coreopsis species differed with C. grandiflora 〉 C. lanceolata 〉 C. rosea, which provide the basis for water management of Coreopsis species. Ch, 4 fig. 1 tab. 24 ref.]